US2901622A

US2901622A - Calutron control device

Info

Publication number: US2901622A
Application number: US711414A
Authority: US
Inventors: Lawrence W Baldwin
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-11-21
Filing date: 1946-11-21
Publication date: 1959-08-25
Anticipated expiration: 1976-08-25

Description

Aug. 25, 1959 L. w. BALDWIN CALUTRON CONTROL DEVICE 5 Sheets-Sheet 1 Filed Nov. 21, 1946 VA C 01/ CONTROL UNIT WINVENTOR.

BY d M MA GIVE 7' CON 7 R01.

M RECTIFIER ARC 1/0; 734 65 Sl/PPL r Hl-VOL 746E PLATE SUPPL V CO/V TROL UNIT 6 T/F/Efi 6 L/M/TER 5 ATTORNEY Aug. 25, 1959 w. BALDWIN CALUTRON CONTROL DEVICE 5 Sheets-Sheet 2 Filed Nov. 21, 1946 OFF OFF

ATTORNEY Aug. 25, 1959 L. w. BALDWIN CALUTRON CONTROL DEVICE 5 Sheets-Sheet 3 Filed Nov. 21, 1946 Q8 VENTOB ATTORNEY Aug. 25, 1959 L. w. BALDWIN CALUTRON CONTROL DEVICE 5 Sheets-Sheet 4 Filed Nov. 21, 1946 OFF OFF

MENTOR Aug. 25, 1959 L. w. BALDWIN CALUTRON CONTROL DEVICE fi llllllllllllllllllllllllll 1||| R. Y 5 M M m m I A m W;

v II United States Patent Q CALUTRON CONTROL DEVICE Lawrence W. Baldwin, San Diego, Calif., assignor to the United States of America as represented by the United States Atomic Energy Commission Application November 21, 1946, Serial No. 711,414

14 Claims. (Cl. 250-413) This invention relates to interlock and control circuits for a calutron.

A calutron is an electromagnetic mass separation apparatus of the type disclosed in U.S. Patent No. 2,709,222 issued to Ernest 0. Lawrence for Method and Apparatus for Separating Materials.

An object of this invention is to provide an interlock system for a calutron in which the ion source cooling water flow switch is interlocked (1) with the current supply to the heaters associated with the ion source, (2) with the cathode current supply, (3) with the are current supply and (4) with the accelerator electrode voltage supply.

Another object of this invention is to provide an interlock system for a calutron in which the cooling water conduits to the tank and liner of the calutron are provided with switches interlocked with the high voltage accelerator electrode supply.

Another object of this invention is to provide an interlock system for a calutron in which the receiver of the calutron is provided with a cooling water supply having a flow switch interlocked with the decelerator electrode supply of the calutron.

Still another object of this invention is to provide an interlock arrangement in a calutron wherein the accelerator electrode voltage supply cannot be operated unless the tank and liner cooling water is flowing and the decelerator voltage supply cannot be operated unless the cooling water to the calutron tank, liner and the receiver is flowing.

Other and further objects of this invention will be apparent to those skilled in the art to which it relates from the following specification, claims and drawings.

Referring to the drawings briefly,

Figure 1 is a schematic wiring diagram of an embodiment of this invention;

Fig. 2 is a schematic wiring diagram of the heater control unit shown in block form in Fig. 1;

Fig. 3 is a schematic wiring diagram of the are control unit shown in block form in Fig. 1;

Fig. 4 is a schematic wiring diagram of the high voltage filament supply control unit shown in block form in Fig. l; and

Fig. 5 is a schematic wiring diagram of the high voltage supply control unit shown in block form in Fig. 1.

Referring to Fig. 1 the calutron 100 illustrated is of the type utilizing a hot ion source; that is, the charge chamber H and the are chamber J are maintained at a high positive potential with respect to the tank T and liner L is grounded. This calutron includes a rectangular tank T which is maintained at a low pressure by means of a vacuum pump 19. Furthermore the tank T is arranged in the air gap of an electromagnet (not shown). The ion source includes a charge chamber H and an arc chamber J arranged at one end of the arcuate liner L. Ion accelerating electrode structure is provided including the arc chamber slit disposed at the front of the chamber J, electrodes G, and electrodes C, the electrodes 2 ,901,622 Patented Aug. 25, 1959 C being disposed on the face of the liner L and the electrodes G being disposed between the front of the arc chamber J and the electrodes C as more fully described in U.S. Patent No. 2,725,478 issued November 29, 1955, to Byron T. Wright for Apparatus for the Separation of Materials.

Three electrical heaters H1, H2, and H3 are arranged in heat communicating relation with various portions of the ion transmitter, the heater H1 being arranged in heat communication with the charge chamber H, the heater H2 being arranged in heat communication with the arc chamber I and the heater H3 being arranged in heat communication with the electrodes C.

A collector E arranged at the opposite end of the liner L includes two pockets P and Q positioned to receive two components of the electromagnetically separated material one of which is enriched with material that is to be recovered.

A thermionically emissive cathode K is arranged in the ion transmitter above a collimating slot (not shown) in the arc chamber J, the purpose of this cathode being to supply electrons for striking an arc in the arc chamber J as more fully described in U.S. Patent No. 2,709,- 222 issued to Ernest 0. Lawrence for Method and Apparatus for Separating Materials. The ion source is sup ported from a side wall of the tank T by means of an insulating bushing B. The thermionically emissive cathode K is supported above the arc chamber I by means of two rigid leads K1 and K2 in the form of squirt tubes which extend through and are insulated from the wall of the tank T by insulators K3 and K4 respectively.

The leads to the cathode K and bushing B which supports the ion source are water cooled by means of water supplied through a line W1. This line W1 includes a valve V1, the cylinder 10 associated with the flow switch S1, coupling 11, cooling coil 12 surrounding portions of the insulator B and water distributor 13 of insulation material associated with the cathode lead squirt tubes K1 and K2. The liner L is water cooled by means of water supplied through a water line W2 insulated from the tank T by

insulators

15 and 16 and including a valve V2 and the cylinder 14 associated with the flow switch S2. The collector E is water cooled by means of water supplied through a water line W3 insulated from the tank T by insulators 16 and 17 and including a valve V3 and cylinder 13 associated with the flow switch S3.

For the sake of brevity no explanation is given here of the details of operation of the calutron itself, since this material is fully described in U.S. Patent No. 2,709,222 issued to Ernest 0. Lawrence entitled Method and Apparatus for Separating Materials.

Referring to Fig. 1, it Will be noted that the electrical circuits associated with the calutron include various voltage supplies and associated elements and also various control units. It will be noted that some of these are interlocked in such a way as to provide for the protection of the calutron itself and for the protection of the individual who operates the calutron. All of the electrical power supplies derive their power from a common four-wire, three-phase alternating current power system. The magnet control unit 20 may be of the type shown in the above-referenced patent to Ernest 0. Lawrence, and the vacuum control unit 21 may be of a design such as those described in application Serial No. 675,567, of Fred H. Schmidt, filed June 10, 1947 now Patent No. 2,888,564, dated May 26, 1959. These control units require no further description here inasmuch as they are not interlocked by means of relays with any of the other electrical devices to be described. 1

The charge chamber heater H1, the arc chamber heater H2, and the heater H3 for electrodes C are connected to the secondaries of well insulated isolation trans? formers T1, T2 and T3 respectively, and the primaries of these transformers are connected to

output terminals

22, 23 and 24 respectively of the heater control unit 25 which is illustrated in detail in Fig. 2. By suitable manipulation of the heater control unit, the amount of heat produced by .the three heaters H1, H2 and H3 may be suitably varied and controlled as hereinbelow described.

The cathode K is connected through an isolation transformer T4 to terminals 26 of the arc control unit 27 shown in detail in Fig. 3. The are voltage supply 28 is provided with five input terminals divided into two

groups

29 and 30, group 29 being connected to the filaments of the rectifier tubes included in the arc voltage supply and group 30 being connected to the plates of the rectifier tubes included in the arc voltage supply. These

input terminals

29 and 30 are connected to

terminals

31 and 32 respectively of the arc control unit 27. The are voltage supply also comprises two output terminals 33 and these output terminals are connected by means of suitable conductors between the cathode K and the arc block which includes the arc chamber 1. The polarity of this connection is so chosen that the arc block is positive with respect to the cathode K.

The high voltage supply includes a decelerating voltage supply and an accelerating voltage supply. The decelerating voltage supply includes a three phase rectifier 34 and a limiter 35. The accelerating voltage supply includes a three phase rectifier 36, a limiter 37, and a regulator 38. The output of the decelerating voltage supply is applied between the electrodes G and C, the electrode C being rendered positive relative to the electrode G in order to decelerate positive ions projected from the arc chamber prior to their entry into the liner L and to form a potential barrier to prevent negatively charged particles from being projected from the space within the liner L to the arc block. The output of the accelerating voltage supply is applied between the arc chamber I and the electrode C, the electrode C being maintained negative relative to the are chamber I by a predetermined amount in order to project positive ions from the arc chamber J into the liner L with a predetermined energy. At this point it should be noted that for satisfactory operation the accelerating voltage applied between the arc chamber J and electrodes G must exceed the decelerating voltage applied between the electrodes G and C in order that the positive ions may enter into the liner L, this result being accomplished readily in the present instance with the circuit arrangement described.

Vacuum tubes in the rectifier 34 are water cooled by means of water supplied through a water line W4 including a valve V4 and the cylinder of a flow switch S4. Vacuum tubes in the limiter 35 are Water cooled by means of water supplied through a water line W including a valve V5. and a fiow switch S5. Vacuum tubes in the rectifier 3.6 are water cooled by means of water supplied through a water line W6 including a valve V6 and' a flow switch S6. Vacuum tubes in the limiter 37 are water cooled by means of Water supplied through a Water line W7 including a valve V7 and a flow switch S7. Vacuum tubes in the regulator 38 are water cooled by means of water supplied through a water line W8 including a valve V8 and a flow switch S8.

The isolationtransformers T1, T2, T3, and T4, the arc voltage supply 28 and the high voltage supply are all enclosed within a room or compartment indicated by the broken line R having a door D therein which operates a door lock switch S9, this door lock switch S9 being closed when the door D is closed and opened when the door is opened.

The flow switch S1 in the water line W1 which cools the ion source is so interlocked with the electric control units that the heaters H1, H2, and H3, the cathode K, theatc voltage supply 28 and the high voltage supply cannot be energized unless an adequate supply of cooling water is flowing through this water line W1. The flow switch S2 in the water line W2 which cools the liner L is so interlocked with the electric control units that the high voltage supply cannot be energized unless an adequate supply of cooling water is flowing through this water line W2 but the heaters H1, H2, and H3 and the cathode K and the arc voltage supply 28 may be energized irrespective of the fiow of water through this line W2. The flow switch S3 in the water line W3 which cools the collector E is so interlocked with the electric control units that the supply 36 cannot be energized unless an adequate supply of cooling water is flowing through this water line W3 but the heaters H1, H2 and H3, the cathode K, the arc voltage supply 28 and the supply 34 may be energized irrespective of the flow of water through this line. The flow switch S4 in the water line W4 which cools parts of the vacuum tubes in the rectifier 34 is so interlocked with the high voltage filament supply control unit 40 that the filaments of the rectifier 34 cannot be energized unless an adequate supply of cooling water is flowing through this water line W4, but the vacuum tubes of the other sections of the high voltage supply may be energized irrespective of the flow of water through this water line W4. The fiow switch S6 in the water line W6 which cools parts of'the vacuum tubes in the rectifier 36 is so interlocked with the high voltage filament supply control unit 40 that the filaments of the rectifier 36 cannot be energized unless an adequate supply of cooling water is flowing through this water line W6, but the vacuum tubes of other sections of the high voltage supply may be energized irrespective of the flow of Water through this water line W6 The flow switches S7, S5, and S8 in the water lines W7, W5, and W8 respectively which cool parts of the vacuum tubes in the limiter 37, the limiter 35, and the regulator 38 are so interlocked with the high voltage filament supply control unit that the filaments of the vacuum tubes, of the M limiter 37 and of the G limiter 35 and of the regulator 38 cannot be energized unless an adequate supply of cooling water is flowing through these water lines W7, W5, and W8 but the vacuum tubes of the G rectifier and the M rectifier may be energized irrespective of the flow of water through these lines W7, W5, and W8. The high voltage filament supply control unit is also interlocked with the high voltage plate supply control unit so that the plates of the vacuum tubes of the entire high voltage supply cannot be energized unless and until the filaments of these vacuum tubes are suitably energized. The door lock switch S9 is so interlocked with the arc control unit, the high voltage filament supply and control unit, and the high voltage plate supply control unit that the high voltage elements Within the room R cannot be energize unless the door D is closed. In, actual practice two sep arate doors were used, one, to a room surrounding the high voltage supplies as illustrated here and another placed adjacent the tank; T so as to provide access to the ion source.

Referring more particularly to, Figures 2, 3, 4, and 5v the details of the various control units, and the interlocks will now be described.

The heater control unit 25 illustrated in Fig. 2 comprises a C heater control network including a'relay R2 and a variac VC for controlling the amountoi heat supplied to the C heater and also comprises a ,l heater control network including a relay R3, and a variac V1 for controlling the amount of heat supplied to the I heater and also comprises an H heater control network including a relay R4 and a variac VH for controlling the amount of heat supplied to the H heater. Also included in this network is a relay R1 which is interlocked with the flow switch S1 controlled by the supply of cooling water associated with the ion source. as will be more fullyexplained hereinbelow. 1

The are control unit 27 illustrated in Fig. 3 comprises a cathode control network including a relay R6 and a saturable rea or SR. for contro l ng h a ount Of cu t supplied to the cathode K and also comprises a I plate supply control network including a relay R16 and a three phase variac VP for controlling the voltage supplied to the plate circuits of the vacuum tubes within the arc voltage supply and also comprises a J filament supply control network including a relay R and a voltage regulator VRJ of a conventional type for controlling the amount of electrical power supplied to the filament circuits of the vacuum tubes of the arc Voltage supply. -In addition, the arc control unit includes a relay .R5 which interlocks the circuit including R6 with the fiow switch S1 as more fully described hereinbelow. And also the arc control unit includes a I and K regulator JKR which serves to stabilize the are produced in the arc chamber I. For details of the regulator JKR reference is made to US. Patent No. 2,745,964 issued May 15, 1956, to Robert De Liban for Are Regulator for Calutron Ion Source. Also the arc control unit includes a relay R13 which is interlocked with the door lock switch S9 to prevent energizing the plate circuit of the arc voltage supply and the plate circuit of the regulator JKR unless the door D is closed. The are control unit also includes a pair of relays R11 and R12 for discontinuing the supply of'power to the plate circuit of the arc voltage supply when an overload occurs therein. -In addition the arc control unit includes a number of relays R7, R8, R9, R13 and R14 which provide further interlocks between various network elements of the arc control unit.

The high voltage filament supply control unit 40 illustrated in Fig. 4 comprises a diode filament control network including relay R17 and regulating transformers SGI, SGZ and SGM and variacs VGFl, VGFZ and VGFM for controlling the power supplied to the filament circuits of the diodes in the G rectifier 34, the diodes in the M rectifier 36, and the vacuum tubes in the M regulator 38. This control unit 40 also comprises an M filament control network including relay R19 and variac VMF for controlling the amount of power supplied to the filaments of the vacuum tubes in the M rectifier. This control unit also comprises a G rectifier filament control network including a relay R21 and a variac VGF for controlling the amount of power supplied to the filaments of the diodes in the G rectifier. Also included in this control unit is a relay R16 which is interlocked with the flow switches S5, S7 and S8 which prevents energizing the filaments of the diodes of the G limiter and the filaments of the diode of the M limiter and the filaments of the vacuum tubes in the M regulator unless all of these vacuum tubes are being supplied with cooling water at suitable rates through the corresponding water flow lines W5, W7 and W8 respectively. Also included in this control network is a relay R18 which is interlocked with the flow switch S6 associated with the M rectifier for preventing the energization of the filaments of the vacuum tubes in the M rectifier unless cooling water is supplied thereto at suitable rates through the water flow line W6. Also included in this control network is a relay R which is interlocked with the flow switch S4 associated with the G rectifier for preventing the energization of the filaments of the vacuum tubes in the G rectifier unless cooling water is supplied thereto at suitable rates through the water flow line W4.

The high voltage plate supply control unit 39 illustrated in Fig. 5 comprises a G supply plate control network including relays R27, R28, R35 and R37 and three phase variacs VGP, for controlling the voltage supplied to the plate circuits of the vacuum tubes of the G supply. This control unit also comprises an M plate supply control network including relays R41, R42 and R43 for controlling the voltage supplied to the plate circuits of the vacuum tubes of the M supply. This control unit also comprises an overload network including overload relays R38, R39, R32 and R33 associated with the G supply and overload relays R44, R45, R34 and R36 associated with the M supply and a recycling network ind eluding relays R29 and R31 which cooperate with the overload network to de-energize and then to re-energize the high voltage supply whenever an overload occurs therein as more fully described hereinbelow. This control unit alsoincludes a time delay relay R22 which is interlocked with the M water supply flow switch S1 and a relay R25 interlocked with the C liner flow switch S2 for preventing the application of high voltage to the ion beam transmitter unless vwater is flowing through the corresponding water lines W1 and W2 at appropriate rates. The time delay relay R22 is also interlocked with the high voltage filament supply control unit as to prevent the application of plate voltages to the plate circuit of the G and M supplies unless the filament of the vacuum tubes therein have been properly energized. This control unit also includes a relay R24 which is interlocked with the door lock switch S9 for preventing the application of high voltage to the plate circuits of either the G or the M supply unless the door D is closed. This control unit also includes a relay R40 which is interlocked with the E water supply flow switch S3 for preventing energization of the M supply and hence for preventing the application of an ion accelerating voltage to the ion beam transmitter unless water is flowing through the E water line. This control unit also includes a holding network including relays R23 and R26 for scaling in relay R27 and bypassing the On button associated therewith. This control unit includes a G step-start system including resistors RG and relays R35 and R37 associated with the G supply and an M step-start system including resistors RM and relays R42 and R43 associated with the M supply, the two-step-start systems being interlocked as more fully described hereinbelow.

Considering now the operation of the calutron control networks in more detail the values V1, V2, V3, V4, V5, V6, V7 and V8 are opened to permit cooling water to flow through the associated water lines to the corresponding elements of the calutron or of the power supplies as the case may be and'the door D is closed. 1

Whenever the door D is closed. the door lock switch S9 operates, thereby operating the relay R13 and closing its contact, this contact remaining closed as long as this relay is operated. Also, when the door lock switch S9 is operated relay R24 is operated thereby closing its contact, this contact remaining closed as long as this relay is operated.

As long as water flows at a sufiicient rate through the water line W1 including the M water supply flow switch S1 the contacts of this flow switch S1 remain closed thereby energizing the coil of relay R1 of Fig. 2 and maintaining its contact closed. When the relay R1 is thus energized the C heater control network is prepared for operation. When this control network is thus prepared for operation the relay R2 therein is operated by depressing the corresponding On button. When this relay R2 is operated the first contact thereof closes and seals this relay in so that it remains operated even when its On button is released. Also when the relay R2 is operated its third and fourth contacts close thereby connecting the associated variac VC to one phase of the power line thus permitting the flow of electrical energy to the C heater. Also when this relay is operated its second contact closes thus preparing for operation the I and H heater control networks. When the J and H heater control networks are so prepared either may be energized independently. When the J heater control network is thus prepared for operation the relay R3 therein is operated by depressing the corresponding On button. When this relay is operated its first contact closes and seals this relay in so that it remains operated even when its On button is released. Also when relay R3 is operated its second and third contacts close thereby connecting the associated variac V] to one phase of the power line thus permitting the flow of electrical energy to the J heater. When the H heater control network is thus 1 zoom 2a prepared for operation the relay R4 therein is operated by depressing the corresponding On button. When this relay is operated its first contact closes and seals this relay in so that it remains operated even when its On button is released. Also when relay R4 is operated its second and third contacts close thereby connecting the associated variac VH to one phase of the power line, thus permitting the flow of electrical energy to the H heater. Thus it will be noted from the foregoing that energy cannot be supplied to either the J heater or the H heater unless the C heater has been previously energized. This interlock arrangement has the advantage of pre-heating the C electrodes so as to prevent the deposition thereon of any vapor effusing from the arc chamber when heat is supplied to the charge chamber H or the I chamber or both.

Also when the relay R1 is energized relay R5 of Fig. 3 operates, thereby closing its contact and preparing for operation the cathode control network. Whenever this control network is thus prepared for operation the relay R6 therein is operated by depressing the corresponding On button. When this relay is operated its first contact closes and seals this relay in so that it remains operated even when its On button is released. Also when the relay R6 is operated its third and fourth contacts close thereby permitting the flow of electrical energy to the cathode K through the saturable reactor SR. Also when this relay R6 is operated its second contact closes, thus energizing the time delay relay R7 which relay thereupon operates after a predetermined time interval has elapsed.

The relay R15 of the J filament supply control network is operated at any time by depressing the corresponding On button. When this relay R15 is operated its first contact seals this relay in so that it remains operated even when the On" button is released. Also when the relay R15 is operated its third and fourth contacts close thereby connecting the voltage regulator VRJ to one phase of the power line thus permitting the flow of electrical energy .to the filaments of the vacuum tubes of the arc voltage supply and also to the filaments of the J K regulator I KR. Also when this relay is operated its second contact closes, thus energizing the time delay relay R14 which relay thereupon operates after a predetermined time interval has elapsed. When the contacts of the time delay relay R14 close a circuit is completed through the second contact of the relay R15 and the contact of the relay R13 which has been previously closed thereby energizing and operating relay R8. When relay R8 operates its contact closes, thereby energizing and operating relay R9. When the relay R9 is operated its first contact closes, thereby completing the fiow of power through the third and fourth contacts of relay R15 and through the voltage regulator VRJ to the plate supply of the J and K regulator JKR. Also when relay R9 operates its second contact closes, thereby preparing for operation the J plate supply control network through a circuit including the normally closed contacts of the overload relays R11 and R12. Whenever this control network is thus prepared for operation the relay R11 therein is operated by depressing the corresponding start button. When this relay is operated its first contact thereof closes and seals this relay in so that it remains operated' even when its On button is released. Also when the relay R is operated the second, third, and fourth con-tacts of this relay close thereby connecting the associated three-phase variac VP to the power line thus permitting the flow of electrical energy to the plate circuits of the arc voltage supply. When the plate circuits of the arc voltage supply are thus energized, the currents flowing through the conductors connecting the three phase variac VP to this plate circuit induce control voltages in the secondaries of the current transformers CT thereby producing alternating current control voltages which are thereupon impressed upon the J and K regulator JKR to effect control of the calutron are as more fully described in U.S. Patent No. 2,745,964 issued May 15, 1956, to Robert DeLiban for Arc Regulator for Oalutron Ion Source.

As long as waterflows through the water lines including the flow switches 55, S7, and S8 the contacts of these flow switches remain closed, thereby operating the relay R16 of Fig. 4 whereby its contact is maintained closed. When the relay R16 is thus energized the control network which controls. the supply of power to the filaments of the vacuum tubes of the G limiter, the M limiter, and the M regulator is prepared for operation. When this control network is prepared for operation the relay R17 therein is operated by depressing the corresponding On button. When this relay is operated its first contact closes and seals this relay in so that it remains operated even when its On button is released. Also when the relay R17 is operated its third, fourth and fifth contacts close, thereby connecting the associated variacs VGFl, VGF2 and VGFM to the power line thus permitting the flow of electrical energy to the filaments of the vacuum tubes of the G limiter, the M limiter, and the M regulator.

As long as water flows through the water line W6 including the M rectifier water supply flow switch S6 the contacts of this flow switch remain closed, thereby energizing the coil of relay R18 and maintaining the contact of this relay R18 closed. When the relay R18 is thus energized the M filament control network is prepared for operation. Whenever this control network is thus prepared for operation the relay R19 therein is operated by depressing the corresponding On button. When this relay is operated the first contact thereof closes and seals this relay in so that it remains operated even when the On button is released. Also when the relay R19- is operated its third and fourth contacts close, thereby connecting the associated variac VMF to one phase of the power line thus permitting the flow of electrical energy to the filaments of the vacuum tubes of the M rectifier.

As long as water flows through the water line W4 including the G rectifier water supply flow switch S4 the contacts of this flow switch remain closed, thereby energizing the coil of relay R20 and maintaining its contact closed. When the relay R20 is thus energized, the G filament control network is prepared for operation. Whenever this control network is thus prepared for operation the relay R21 therein is operated by depressing the corresponding On button. When this relay is operated its first contact closes and seals this relay in so that it remains operated even when its On button is released. Also when the relay R21 is operated the third and fourth contacts of this relay close, thereby connecting the associated variac VGF to one phase of the power line thus permitting the flow of electrical energy to the filaments of the vacuum tubes of the G rectifier.

When all three relays R17, R19, and R21 are thus closed and the relay R1 is also closed, a circuit to the coil of the time delay relay R22 in the high voltage control network unit is completed through the contact of relay R1, the second contact of' relay R17, the second contact of relay R19, and the second contact of relay R21. When the circuit including the relay coil of this time delay relay R22 has been completed for a predetermined time interval, this relay operates and its contact closes.

As long as water flows through the water line W2 associated with the C liner the contacts of the corresponding flow switch S2 remain closed, thereby operating the relay R25 and maintaining its contact closed. Also as long as water flows. through the water line W3 associated with the collector E the contacts of the corresponding fiow switch S3 remain closed thereby operating the relay R44) and maintaining its contact closed. When the relays R22, R24,.R'25 and R4tl-are all operated the high voltage plate supply control unit is prepared for operation. When this control network unit is so prepared for operation the G and M supplies may be operated individually or the G and M suppliesmay be. operated together as more fully set forth below.

Considering first the operation of the high voltage plate supply control unit when the G and M voltage supplies are to be energized individually, it is necessary to energize the G supply before the M supply. 'To initiate operation of the G supply, relay R27 is operated by depressing the G On button, thus completing a circuit including the coil of relay R27, the contact of relay R26, the G Off button, and the contacts of relays R22, R24, and R25. When the second contact of relay R27 closes, a circuit is completed including the second contact of relay R31 and the coil of relay R23 and the G Off button and the contacts of relays R22, R24 and R25, thereby operating relay R23 and closing its contacts. Also, when the second contact of relay R27 closes, a circuit is completed including the second contact of relay R31, the first contact of relay R28, the coil of the slowto-make time delay relay R29, the contact of relay R26, the G Off button, and the contacts of relay R22, R24 and R25, this relay, however, not operating since its circuit is broken before it has time to operate, as more fully explained below.

When the first contact of relay R27 closes, a circuit is completed including the contact of relay R26, the G On button, the G Off button and the contacts of relays R22, R24 and R25 thereby operating relay R28 and opening its first contact and closing its second contact,

When the first contact of relay R23 closes, a holding circuit is completed including the coil of this relay, its first contact, the G Off button and the contacts of relays R22, R24 and R25, thus bypassing the G On button. When the second contact of the relay R23 closes, relay R26 operates and its contact opens, thereby opening the circuit between relay R27 and the G On button. However, relay R27 remains operated, this relay R27 now being energized through a circuit including the second contact of relay R31, the second contact of relay R27 and the first contact of relay R23, as well as the G Off button and the contacts of relays R22, R24 and R25. Also relay R28 remains operated, this relay R28 now being energized through a circuit including the first contact of relay R23, the G Off button, and the contacts of relays R22, R24 and R25. It is to be noted that when the relay R26 has thus been operated, depressing the G On button has no effectupon the G high voltage control unit.

It is to be noted that in the foregoing sequence of operation relay R28 operates after R27 and relay R26 after relays R27 and R23, thus insuring sealing in relays R27 and R28 around the G On button and at the same time rendering the G On button inoperative.

When the first contact of relay R28 opens the coil of the time delay relay R29 is de-energized, thereby preventing this relay R2 from operating at this time. When the second contact of relay R28 closes a circuit is com pleted including the G Off button, the contacts of relays R22, R24 and R25, and the coil of the power relay R35. When this circuit is completed the power relay R35 operates and its contacts close. When the second, third, and fourth contacts of the power relay R35 close, the plate circuits of the G rectifier are connected to the power line through the three phase variac VGP, these three contacts and the resistors RG, thereby applying a voltage of intermediate G value to the G supply. When the first contact of the power relay R35 closes, a circuit is completed including the coil of the time delay power relay R37, the second contact of relay R28, the G Off button and the contacts of relays R22, R24, and R25, thus energizing the time delay relay R37 which thereupon operates after a predetermined time interval has elapsed. When the time delay relay R37 operates its second, third and fourth contacts close, thereby shorting out the resistors RG and connecting the G supply to the power line through the three phase variac VGP and these three contacts, thereby raising the voltage applied to the plate circuits of the G supply from the intermediate G value mentioned to the final full G value. Also when the time delay relay R37 operates its first contact closes, thereby preparing a circuit for subsequently automatically operating the M step-start system of the M supply control network as more fully set forth hereinbelow.

At this time the G supply may be 'de-energized if desired by depressing the G Off button. When the G Off button is thus depressed relay R23 is de-energized and restored thereby opening its contacts, When the second contact of relay R23 is thus opened relay R26 is ale-energized and restored, closing its contact. Also when the G Off button is thus depressed relay R27 is deenergized and restored, the contacts of relay R27 opening. When the first contact of relay R27 opens, relay R28 is de-energized and restored, its first contact closing and its second contact opening. Also at the time when the G Off button is thus depressed relays R35 and R37 are de-energized and restored. When relays R35 and R37 are thus restored, their contacts open and the plate circuits of the G supply are disconnected from the power line.

Continuing the consideration of the operation of the high voltage control unit by individual operation of the G and M voltage supplies, consider now the operation of the M voltage supply while the G supply is fully energized as previously described. At this time it will be recalled that the contact of relay R40 is closed by virtue of the operation of the E water flow switch S3 as previously described. Also, at this time it will be recalled that the first contact of relay R35 and the first contact of relay R37 are closed by virtue of the operation of the G voltage control network as previously described thereby preparing the M step-start system associated with the M supply for operation. When the M voltage supply control unit is thus prepared for operation, to initiate operation of the M supply, relay R41 is operated by depressing the M On button, thus completing a circuit including the coil of relay R41, the M Off button, the contact of relay R40, the G Off button and the contacts of relays R22, R24 and R25, thereby closing the contacts of relay R41. When the first contact of relay R41 closes it completes a circuit bypassing the G On button but has no further effect at this time, because of the prior operation of the G control unit. When the second contact of relay R41 closes, this relay is sealed in by completion of a sticking circuit that bypasses the M On button. When the third contact of relay R41 closes, a circuit is completed including the first contact of relay R35, the second contact of relay R28, the G Off button, the contacts of relays R22, R24 and R25 and the coil of power relay R42. When this circuit is completed the power relay R42 operates and its contacts close. When the second, third and fourth contacts of this power relay R42 close the plate circuits of the M rectifier are connected to the power line through -these three contacts and the resistors RM, thereby applying voltage of intermediate M value to the M supply. When the first contact of the power relay R42 closes a circuit is completed including the first contact of the time delay relay R37, the first contact of the relay R35, the second contact of relay R28, the G Off button and the contacts of relays R22, R24, and R25, and the coil of the time delay power relay R43. When this circuit is complete the time delay power relay R43 is energized, thereby causing this relay R43 to operate after a predetermined time interval. When the time delay relay R43 operates its three contacts close, thereby shorting out the resistors RM and connecting the M supply to the power line through these three contacts, thereby raising the voltage applied to the M rectifier from the intermediate value M mentioned to the final full M value.

To de-energize the M supply alone at this time the M "OfF button is depressed, thereby de-energizing and restoring relay R41, opening its contacts. When the third contact of relay R41 is thus opened relay R42 is deenergized and restored, opening its contacts. At this time the opening of the second, third, and fourth. contacts of relay R42 disconnects the resistors RM completely while the simultaneous opening of the first contact of relay R42 de-energizes and restores relay R43, thereupon opening its contacts. When the contacts of relay R43 are thus opened the plate circuits of the M rectifier are disconnected from the power line. The G supply may then be de-energized in the manner hereinbefore described.

To de-energize both the G and the M supplies together, the G OE button is depressed, thus de-energizing and restoring relays R23, R26, R27, R28, R35, R37, R41, R42, and R43 immediately and disconnecting both the G and the M rectifiers from the power line.

Considering now the operation of the high voltage control unit when the G and M voltage supplies are to be energized together, the M On button is depressed without previously operating the G On button. When the M On button is thus depressed, relay R41 operates and its contacts close as previously mentioned. At this time when the second contact of the relay R41 closes it completes a sticking circuit as previously described. When the third contact of relay R41 closes, the circuit to relay R42 is only partially completed, this relay not becoming energized at this time because the second contact of relay R28 and the first contact of relay R35 are still open. When the first contact of relay R41 closes, it completes a circuit shunting the G On button, thus having the same efiect as depressing the G On button and completing a circuit including the coil of relay R27 and thereupon operating relays R23, R26, and R28 in the manner previously described.

At the time when the second contact of relay R28 closes, the circuit to the power relay R35 is completed in the manner previously described, causing the power relay R35 to operate and its contacts to close after a predetermined time interval. When the second, third and fourth contacts of the power relay R35 close, a voltage of intermediate G value is applied to the G rectifier as previously described. When the first contact of the power relay R35 closes, the circuit is completed including the third contact of relay R41 and the coil of relay R42, thereby operating this relay R42, causing its second, third and fourth contacts to close, thereby applying a voltage of intermediate M value to the M rectifier shortly after the intermediate value of voltage previously mentioned was applied to the G rectifier. When the first contact of relay R42 closes the circuit of time delay relay R43 is only partially completed, this relay not becoming energized at this time because the first contact of time delay relay R37 is still open. Also when the first contact of relay R35 closes, time delay power relay R37 is energized and thereupon operates after a predetermined time interval has elapsed. When the power relay R37 operates, its second, third and fourth contacts close, thereby raising the voltage applied to the G supply from the intermediate G value mentioned to the final full G value. Also at the time when the time delay relay R37 operates its first contact closes, thereby completing the circuit including the coil of the relay R43 which thereupon operates after a predetermined time interval has elapsed. When the time delay relay R43 operates its contacts close, thereby causing the voltage applied to the M rectifier to be raised from the intermediate M value mentioned to its final full M value, this occurring subsequent to the application of full G voltage to the G rectifier.

Considering now the operation of the high voltage control unit when an overload occurs in the G supply, when such an overload occurs, the currents increase in at least 12 two of the conductors connecting the plate circuits of the G rectifier to the power line thereby increasing the current induced in the secondary of at least one of the current transformers CG whereby at least one of the associated overload relays R38 and R39 operates. When either of these overload relays R38 and R39 operates, its contact closes, completing a circuit including the coil of relay R32, thereby closing its contacts. When the first contact of relay R32 closes, a circuit is completed including the coil of the slow-to-make time delay relay R31. When the second contact of relay R32 closes, a circuit is partially completed including the coil of the indicator relay R33. If the time delay relay R31 remains energized by virtue of the continuation of an overload in the G supply suflicient to operate either overload relay R38 or R39 for a time greater than a predetermined time interval of, for example, 0.7 second, this relay R31 operates closing its first contact and opening its second contact, When the first contact of time delay relay R31 closes the cir cuit including the coil of the indicator relay R33 is further prepared for operation. When the second contact of the; time delay relay R31 opens, the coils of relays R27 and R28 are de-energized, thereby restoring these two relays R27 and R28. When relay R28 is thus restored, its second contact opens, thereby de-energizing the coils of relays R35, R37, R42 and R43, thereby restoring these relays and de-energizing both the G and the M supplies by disconnecting their plate circuits from the power line. Also when relay R28 is restored but prior to the disconnection of the G and M supplies from the power line, its first contact closes, thereby completing the circuit including this contact and the coil of time delay relay R29. Also when the first contact of relay R28 closes, a circuit is completed which includes the coil of relay R33, the second contact of relay R32, the first contact of relay R31, the first contact of relay R28, the first contact of relay R23, the G Off button, and the contacts of relays R22, R24 and R25 causing relay R33 to operate and its contact to close whereupon an indicator light (not shown) connected in parallel with the coil of relay R33 becomes illuminated indictaing that an overload has occurred in the G supply. When the contact of this relay R33 closes, an indicator sticking circuit is completed including the coil of this relay, its contact, the first contact of relay R28, the first contact of relay R23, the G 011? button, and. the contacts of relays R22, R24 and R25. At the time that the G supply is disconnected, the overload condition therein is removed and the overload relays R38 and R39 and the relay R32 are restored, the indicator relay R33 remaining operated temporarily by virtue of the prior completion of the indicator sticking circuit heretofore referred to. When relay R31 restores, its second contact closes thereby preparing a circuit including the relay R27 for reoperation. Subsequently, when the time delay relay R29 operates, its contact closes, thereby completing the circuit including the coil of relay R27 and the second contact of relay R31 whereby relay R27 reoperates and its contacts close. The closing of the second contact of relay R27 seals in the circuit including this contact and the coil of relay R27. The closing of the first contact of the relay R27 completes the circuit including the coil of relay R28. When the latter circuit is completed, relay R28 reoperates, closing its second contact and thereby causing power relay R35, power relay R42, time delay relay R37 and time delay relay R43 to operate in sequence in the order named whereby a voltage of intermediate value is applied to the G rectifier and then a voltage of another intermediate value is applied to the M rectifier and then the full voltage is applied to the G rectifier and then the full voltage is applied to the M rectifier. Also, when relay R28 reoperates, its first contact opens, thereby de-energizing and restoring relay R29 and relay R33. It is to be noted that when relay R29 restores and its contact opens, relay R27 and relay R28 remain operated by virtue of the prior closing of the second contact of relay R27. Thus the high voltage control unit is returned to its fully operated condition.

Similarly, considering now the operation of the high voltage plate supply control unit when an overload occurs in the M supply, when such an overload occurs, the currents increase in at least two of the conductors connecting the plate circuits of the M rectifier to the power line, thereby increasing the current induced in the secondary of at least one of the associated current transformers CM, whereby at least one of the overload relays R44 and R45 operates. When either of these overload relays R44 and R45 operates, its contact closes, completing a circuit including the coil of relay R34, thereby closing its contacts. When the first contact of relay R34 closes, a circuit is completed including the coil of the slow-to-make time delay relay R31. When the second contact of relay R34 closes, a circuit is partially completed including the coil of the indicator relay R36. If the time delay relay R31 remains energized by virtue of the continuation of an overload in the M supply sufficient to operate either overload relay R44 or R45 for a time greater than a predetermined time interval of, for example, 0.7 second, this relay R31 operates closing its first contact and opening its second contact. When the first contact of time delay relay R31 closes, the circuit including the coil of indicator relay R36 is further prepared for operation. When the second contact of the time delay relay R31 opens, the coils of relays R27 and R28 are de-energized, thereby restoring these two relays R27 and R28 as previously described. When relay R28 is thus restored, its second contact opens, thereby de-energizing the coils of relays R35, R37, R42 and R43, thereby restoring these relays and de-energizing both the G and the M supplies by disconnecting their plate circuits from the power line. Also, when relay R28 is restored but prior to the disconnection of the G and M supplies from the power line, its first contact closes, thereby completing the circuit including this contact and the coil of relay R29. Also, when the first contact of relay R28 closes, the circuit is completed which includes the coil of relay R36, the second contact of relay R34, the first contact of relay R31, the first contact of relay R28, the first contact of relay R23, the G Ofi button, and the contacts of relays R22, R24, and R25 causing relay R36 to operate and its contact to close whereupon an indicator light (not shown) connected in parallel with the coil of relay R36 becomes illuminated indicating that an overload has occurred in the M supply. When the contact of this relay R36 closes, a sticking circuit is completed including the coil of this relay, its contact, the first contact of relay R28, the first contact of relay R23, the G Off button, and the contacts of relays R22, R24 and R25. At the time that the M supply is disconnected, the overload condition therein is removed and the overload relays R44 and R45 and the relay R34 are restored, the indicator relay R36 remaining operated by virtue of the prior completion of the indicator sticking circuit heretofore referred to. When relay R31 restores, its second contact closes, thereby preparing a circuit including the relay R27 for reoperation. Subsequently, when the time delay relay R29 operates, its contact closes, thereby completing the circuit including the coil of relay R27 and the second contact of relay R31. When relay R27 operates, its contacts close. The closing of the second contact seals in the circuit including this contact and the coil of relay R27. The closing of the first contact completes the circuit including the coil of relay R28. When the latter circuit is completed, relay R28 reoperates, closing its second contact and thereby causing power relay R35, power relay R42, time delay relay R37 and time delay relay R43 to operate in sequence in the order named whereby a voltage of intermediate G value is applied to the G rectifier and then a voltage of intermediateM value is applied to the M rectifier and then the full G voltage is applied to the G rectifier and then the full M voltage is applied to the M rectifier. Also, when relay R28 reoperates, its

14 first contact opens, thereby de-energizing and restoring relay R29 and relay R36. It is to be noted that when relay R29 restores and its contact opens, relay R27 and relay R28 remain operated by virtueof the prior closing of the second contact of relay R27. Thus the high voltage control unit is returned to its fully operated condition.

It is to be understood, of course, that all of the electrical supplies can be de-energized by depressing the appropriate 01f buttons shown, taking due regard for the various interlocks.

What is claimed is:

1. In a calutron having an evacuated tank disposed in a magnetic field, an ion source comprising an arc block disposed in said tank, arc block cooling means including conduits arranged in heat exchange relationship with said are block, a charge chamber communicating with said arc block, an electrode structure disposed adjacent said are chamber and adapted .to transmit ions from said arc chamber through said magnetic field along predetermined trajectories, first, second, and third heating means respectively arranged in heat exchange relationship with said electrode structure and said charge chamber and said are chamber, an alternating current power supply, first, second, and .third control circuits respectively associated with said first, second, and third heating elements, means responsive to the flow of cooling medium through said cooling medium supply at a rate above a predetermined rate for preparing said first circuit for operation, means controlled by the operation of said first control circuit for supplying electric power from said alternating current power source to said first heating elements whereby said electrode structure is heated, means controlled by the operation of said second control circuit for supplying electric power from said alternating current power source to said second heating element whereby the temperature of said charge chamber is raised and the charge therein vaporized, and means controlled by the operation of said third control circuit for supplying electric power from said alternating current power source to said third heating element whereby the temperature of said are chamber is raised.

2. In a calutron having an evacuated t-ank disposed in a magnetic field, an ion source comprising an arc block disposed in said tank, arc block cooling means including conduits arranged in heat exchange relationship with said are block, a cooling medium supply control means arranged externally of said tank, a change chamber communicating with said are block, an electrode structure disposed adjacent said arc chamber and adapted to transmit ions from said arc chamber through said magnetic field along predetermined trajectories, first, second, and third heating means respectively arranged in heat exchange relationship with said electrode structure and said charge chamber and said arc chamber, an alternating current power supply, first, second, and third control circuits respectively associated with said first, second, and third heating elements, means responsive to the flow of cooling medium through said cooling medium supply at a rate above a predetermined rate for preparing said first circuit for operation, means controlled by the operation of said first control circuit for supplying electric power from said alternating current power source to said first heating elements whereby said electrode structure is heated, means responsive to the operation of said first control circuit and to the flow of cooling medium supplied at a rate above a predetermined rate for preparing said second and third control circuits for operation, means controlled by the operation of said second control circuit for supplying electric power from said alternating current power source to said second heating element whereby the temperature of said charge chamber is raised and the charge therein vaporized, and means controlled by the operation of said third control circuit for supplying electric power from said alternating current power source to said third-heating elements whereby the temperature of said arc chamber is raised.

3; In a calutron having an evacuated tank including a wall structure having an opening therein, an auxiliary chamber at said opening, an ion source comprising an arc block disposed in said tank adjacent said wall structure, .a thermally emissive cathode, retractable means supportable from the tank wall andinsertable through said auxiliary chamber for holding saidcathode adjacent said are block, a tank door adapted for placement in a safety position outside of said tank, said tank door providing access to said retractable means only when said tank door is removed therefrom, a cathode supply circuit and a control network therefore, means controlled by operation of said control network for effectively connecting said cathode to said cathode supply, and means controlled by removal of said tank door from its safety position for disconnecting said cathode from said cathode supply.

4. In a control network for a calutron including an ion source having an arc block, a first electrode structure disposed adjacent said are block, a secondelectrode structure disposed intermediate said are block and said first electrode structure, the combination which comprises means for sequentially establishing an ion decelerating field between said electrode structures and an ion accelerating field between said arc block and said second electrode structure ,-and means for removing'both fields substantially simultaneously.-

5. In a calutron having an evacuatedtank, a plurality of ion sources disposed therein adapted to produce a plurality of coupled ion beams, a plurality of arc generating means individually associated with said ion sources, a plurality of control devices individually associated with saidion generating means and operative to selectively energize the corresponding individual ion generating means, and means responsive to an excess of current in any individual ion generating means for selectively de-energizing the corresponding individual ion generating means whereby the arc in the corresponding ion source is extinguished.

6. In a calutron having an evacuated tank, an ion source comprising an arc block disposed in saidtank, the first electrode structure disposed adjacent said are block and adaptedto transmit ions therefrom along a predetermined path, a second electrode structure disposed intermediate said are block and said'fi-rst electrode structure, a source of alternating currentpower, a first power supply operatively connected between said are block and said first electrode structure,- a secondpower supply operatively connected between said are block and said secnd electrode structure, first and second start means respectively associated with said first and secondpower supplies, first and second switching means respectively associated with said first and second power supplies, said rst switching means comprising first and second relay members, said second relay member including .a time delay relay, said second switching means comprising first anclsecond relay members, the latter second relay member including atime delay relay, first and second iauxi-liaryrelay means,- reset means including a time delay relay, means responsiveto operation of said second start means for' operating said first auxiliary rela'y means, means responsive to operation of said first auxiliary relay means for operating said second relay means and for initiating operation of the first relay member of said first switching means, means responsive to operation of said second auxiliary relay means for disconnecting said first auxiliary relay means from said second start means and for retaining said first auxiliary relay means operated, means responsive to operation of said first and second auxiliary relay means for preparing said reset means-for operation, means responsive to' operation of this firstr elay member for applying anintermediate voltage to said secem ower supply and for initiating operation of the sec'-' ond relay member of said second switching means, means responsive to the operation of this second relay memher for applying full voltage to said second power.sup' ply after a predetermined time interval, means trespas 16 sive to operation of the first relay member of said second switching means and to operation of said first start means foi operating the first relay member of said f rst switching-means, means responsive to operation of this first relay {means for applying an intermediate voltage to said first power supply, means responsive to operation of the second relay member of said second switching rneans to the ioperation of the first relay member of said first switching means for initiating operation of the second relay member ofsaid first switching means whereby full voltage is applied to the first power supply after a predetermined time interval, means responsive to an overload-in the input of either or both power supplies or in the output of the first power supply fora period exceeding a predetermined time interval for de-energizing said first auxiliary relay means whereby said reset means is operated and voltage is removed from the input of said power supplies, meansresponsive to operation of said reset means for re-operati-ng said first auxiliary relay means after a predetermined time interval whereby voltage is again applied to said power supplies in the aforementioned sequence, manual stop ,rineans for disconnecting both of said power supplies from said source ofalternating current power substantially simultaneously, and manual stop means for selectively disconnecting only the first power supply from said source of alternating current power.

7. In a calutron having an evacuated-tank, an ion source comprising an arc block disposed in said tank, a thermally emissive are cathode disposed in said tank adjacent said are block, arc block cooling means including conduits arranged in heat exchange relationship with said are block and including a cooling medium supply control means arranged externally of said tank, a source of alternating current, an arc cathode supply circuit (including a step-down isolation transformer) operatively connected to said are cathode, an arc voltage supplyoperatively connected between said are cathode and said are block, a tank door adapted for placement in a safety position outsideof said tank adjacent said source, said tank door when removed from its safety position providing access to the tank wall at a point adjacent said source, a protective structure having walls enclosing said cathode supply circuit, said are voltage supply and said emission regulator circuit, a protective door in the wall .of .said structure providing access thereto, first, second, andlthird control means, .means controlled by operation of said first-control means for supplying alternating current power to the cathodeheating circuit of said and voltage supply and to the cathode heating circuit of said emission'regulator circuit, means responsive both to the placement of saidtank door in its safetyposition and to the flow of said cooling medium through said cooling' medium supply control means at a rate in excess of a predetermined rate for preparing said second control circuit for operation, means controlled by the operation of said second control-circuitwhen so preparedfor connecting said cathode supply circuit to said sourceof alternating current power, means including time delay relay means controlled by operation of both said first and second control circuits and responsive-to placement of said tank door in its safety position and .to closing of said protectivedoor for connecting the plate circuit of said emission regulator to said sourceof alternating current power and for preparing said third control circuit for operation, means controlled by operation of said third control circuit for connecting the plate circuit of said are voltage supply, to said source of alternating current power. I

8. In a calutron havingan evacuated tank, an ion source comprising an arc block disposed in sa'id tank, a thermally emissive arc' cathodedisposejd in said tank ad jacentsaid arc block arc block cooling means including conduits arranged; in heat exchange relationship with said arc' block and including a" cooling medium supply control me nsarranged externally of said tank, a source of block, a tank door adapted for placement in a safety position outside of said tank adjacent said source, said tank door when removed from its safety position providing access to the tank wall at a point adjacent said source, a protective structure having walls enclosing said cathode supply circuit, said are voltage supply and said emission regulator circuit, a protective door in the wall of said structure providing access thereto, first, second, and third control means, means controlled by operation of said first control means for supplying alternating current power to the cathode heating circuit of said are voltage supply and to the cathode heating circuit of said emission regulator circuit, means responsive both to the placement of said tank door in its safety position and to the fiow of said cooling medium through said cooling medium supply control means at a rate in excess of a predetermined rate for preparing said second control circuit for operation, means controlled by the operation of said second control circuit when so prepared for connecting said cathode supply circuit to said source of alternating current power, and means including time delay relay means controlled by operation of both said first and second control circuits and responsive to placement of said tank door in its safety position and to closing of said protective door for connecting the plate circuit of said emission regulator to said source of alternating current power and for preparing said third control circuit for operation.

9. In a calutron having an evacuated tank including a wall structure having an opening therein, an ion source comprising an arc block disposed in said tank adjacent said wall structure, a thermally emissive cathode, retractable means for supporting said cathode from the tank wall adjacent said are block, a tank door adapted for placement in a safety position outside of said tank, said tank door providing access to said retractable means only when said tank door is removed therefrom, a cathode supply circuit, a control network associated with said cathode supply circuit, means controlled by operation of said control network and placement of said tank door in its safety position for effectively connecting said cathode to said cathode supply, and means controlled by removal of said tank door from its safety position for disconnecting said cathode from said cathode supply.

10. In a calutron having an evacuated tank, an ion source comprising an arc block disposed in said tank, a thermally emissive arc cathode disposed in said tank adjacent said are block, a source of alternating current power, an arc cathode supply circuit operatively connected to said are cathode, an arc voltage supply operatively connected between said are cathode and said are block, said arc voltage supply having a cathode heating circuit and an anode circuit, an emission regulator circuit responsive to the amplitude of alternating current supplied to the anode circuit of said are voltage supply adapted to control the alternating current supplied to said are cathode supply circuit whereby the current flowing between said thermally emissive cathode and said arc block is maintained substantially constant, said emission regulator circuit having a cathode heating circuit and an anode circuit, first, second, and third control means, means controlled by operation of said first control means for supplying alternating current power to the cathode heating circuit of said are voltage supply and to the cathode heating circuit of said emission regulator circuit, means controlled by operation of said second control circuit for connecting said are cathode supply circuit to said source of alternating current power, means including time delay relay means controlled by operation of both said first and second control circuits for connecting the plate circuit of said emission regulator to said '18 source of alternating current power, and for preparing said third control circuit for operation, and means controlled by operation of said third control circuit for connecting the plate circuit of said are voltage supply to said source of alternating current power.

11. In a calutron having an evacuated tank, an ion source comprising an arc block disposed in said tank, a thermally emissive arc cathode disposed in said tank adjacent said are block, a source of alternating current power, an arc cathode supply circuit operatively connected to said are cathode, an arc voltage supply operatively connected between said are cathode and said are block, said are voltage supply having a cathode heating circuit and an anode circuit, an emission regulator circuit responsive to the amplitude of alternating current suppliedto the anode circuit of said are voltage supply adapted to control the alternating current supplied to said are cathode supply circuit whereby the current flowing between said thermally emissive cathode and said are block is maintained substantially constant, said emission regulator circuit having a cathode heating circuit and an anode circuit, first, second, and third control means, means controlled by operation of said first control means for supplying alternating current power to the cathode heating circuit of said are voltage supply and to the cathode heating circuit of said emission regulator circuit, means controlled by operation of said second control circuit for connecting said are cathode supply circuit to said source of alternating current power, and means including time delay relay means controlled by operation of both said first and second control circuits for connecting the plate circuit of said emission regulator to said source of alternating current power, and for preparing said third control circuit for operation.

12. In a control network for a calutron having an ion source comprising an arc block, a first electrode structure disposed adjacent said are block, a second electrode structure disposed intermediate said are block and said first electrode structure, the combination which comprises: a power source, a first power supply operatively associated with said first and second electrode structures, a second power supply operatively associated with said first electrode structure and said are block, first and second start means respectively associated with said first and second power supplies, common manual means for initiating operation of both start means, separate manual means for initiating operation of said first start means, first and second switching circuits respectively associated with said first and second power supplies, said first switching circuit comprising first and second relay members said second relay member including a time delay relay, said second switching circuit likewise comprising first and second relay members the latter second relay member also including a time delay relay, first and second auxiliary relay means, a reset circuit including a time delay relay, means responsive to initial operation of said first start means for initiating operation of said first auxiliary relay means, means controlled by operation of said first auxiliary relay means for operating said second auxiliary relay means and for operating the first relay member of said first switching circuit, means controlled by operation of said second auxiliary relay means for disconnecting said first auxiliary relay means from said first start means and for retaining said first and second auxiliary relay means operated, means controlled by operation of the first relay member of said first switching circuit for initiating operation of the second relay member of said first switching circuit and for connecting said first power supply to said power source and applying a voltage of intermediate value thereto, means controlled by operation of the second relay member of said first switching circuit for raising the voltage of said first power supply from said intermediate value to a higher value after a predetermined time interval, means controlled by 19. operation ofthefirst relay member of said first switching circuitand'by operation of said second start means for operating the first relay member of said second switching circuit whereby the second power supply is connected to said power source and a voltage of intermediate value is applied thereto, means controlled by operation of the second relay memberof said first switching circuit and operation oftheifirst relay member of said second switching circuit for initiating operation of the second relay member of said second switching circuit whereby the voltage applied to the second power supply is raised. from an intermediate ,value to a higher value after a predetermined time interval, means controlled by initial operation of said first and second auxiliary relay means for initially preparing said reset circuit for operation, means responsive'to an overload in the input of either power supply or in the output of the second power supply for a period exceeding a predetermined time interval for restoring said first auxiliary relay means whereby said reset circuit is operated and said power supplies are disconnected from said power source, means responsive to operation of said reset circuit for reoperating said first auxiliary relay means after a predetermined time interval whereby said switching circuits are operated again and said reset circuit is again prepared for operation, manual stop means for disconnecting said power supplies from said power source substantially simultaneously and manual stop means for disconnecting o-nly'the second said second heating means permitting the operation of said first heating means.

14. In an ionic discharge device, a reservoir contain-- ing charge material to be vaporized, an electrode structure, first and second electrical heating elements respectively arranged in heat exchange relationship with said reservoir and said electrode structure, means for supplying electric power to said electrical heating elements, and means responsive to the application of electric power to said second electrical heating element permitting the application of electric power to said first electrical heating element, thereby preventing the distillation of said charge material from said reservoir to said electrode.

No references cited.