US2713641A - Calutron structure - Google Patents

Description

July 19, 1955 B. T. WRIGHT ETAL CALUTRON STRUCTURE Filed April 25. 1946 3 Sheets-Sheet 1 /2 INVENTOR La wrencea' Ernesi O.

BY Byron T M r-1972i.

y 1955 B. T. WRIGHT ETAL 2,713,641

CALUTRON STRUCTURE Filed April 25, 1946 3 SheetsS'neet 2 In; E.

INVENTOR-SI Ernesi QLaa/renpe a ByT-On T P1 72 722.

July 19, 1955 B. T. WRIGHT ET AL CALUTRON STRUCTURE 5 Sheets-Sheet 3 Filed April 25. 1946 INVENTORS. wrence 9 Ernes 0. La

United States Fateut p w a a dire tiuiy ta, tees 2,713,641 CALUTRON STRUCTURE Application April 25, 1946, Serial No. 664,734 4 Claims. (Cl. 250-413) This invention relates to calutrons and operation thereof, a calutron being an electromagnetic type of isotope separating earlier sole application of Ernest 0. Lawrence, Serial No. 557,784, filed October 9, 1944. In this type of isotope separating apparatus as will more clearly appear from the detailed description below, there is employed an ion source wherein vapor of a material the isotopes of which it is desired to separate is caused to issue from a chamber through a slit therein, and it is ionized in or in the vicinity of the slit. Positive ions passing through the slit are withdrawn and accelerated by an accelerating electrode also having a slit formation adjacent the slit in the chamber of the ion source. The accelerated charged particles, that is positive ions, are caused to move in arcs of a circle under the influence of a strong magnetic field, and are brought to a focus approximately from the point of origin, that is, particles of the same nuclear mass coming to a focal point approximately 180 from the point of origin and the focal points of particles having different nuclear mass being spaced apart a sufiicient distance to enable the components of different nuclear mass, that is different isotopes, to be separately collected. The operation of the calutron de pends upon a number of rather critical variable factors in order to effectively segregate and collect the desired isotopes and one of these critical factors is the relationship of the accelerating electrode to the exit slit of the ion source, that is, the geometry as respects these particular elements. More particularly, it is known that operation can be improved by having the accelerating electrode offset laterally slightly as respects the exit slit in the ion source.

The object of our invention is to control the calutron operation by adjusting the amount of this offset by bodily rotating the ion source itself on trunnions so that the amount of offset of the exit slit in the ion source relative to the accelerating electrode is thereby adjusted. The benefit to be derived from this manner of varying the offset and the mechanical advantages flowing therefrom, as well as many additional advantages of our invention, will become apparent from the following detailed description and annexed drawings wherein:

Fig. l is a diagrammatic showing in cross section, with certain parts broken away, of a calutron having our invention embodied therein.

Fig. 2 is a sectional View taken along the line 22 of Fig. 1.

Fig. 3 is a view partly in section of a portion of Fig. 1, this portion involving the improvements embracing our invention therein.

Fig. 4 is a detailed view in elevation of a part of the structure of Fig. 3.

Referring to Fig. l of the drawings, the calutron shown thereon embodies a tank of generally rectilinear shape as may be observed from the view of Fig. 2, one side of the tank being closed and sealed by a faceplate 11 which is attached to the tank by means of screw clamps 12. The tank and the faceplate 11 having mutually engageable bearing surfaces such as to form an air-tight seal between the tank and the faceplate when the parts are in assembled relationship. The tank in operation is evacuated to a relatively low pressure, that is, a high vacuum suitable for the process of separating isotopes electromagnetically. The tank has an outlet 13 connected by evacuating conduit 14 to a diffusion pump or pumps which are connected to a rotary mechanical pump or pumps 16. The mechanical pump or pumps 16 may be Kinney pumps. In other words, the discharge of the diffusion pumps is connected to the suction side of the mechanical pump or pumps 16. The tank 10 has a number of windows 2%, 2.1, and 22 through which various of the operating parts and the process within the may be observed. The tank to is disposed in a relatively strong magnetic field which is in a direction transverse to the tank, that is, in a direction which would be normal to the paper in Fig. l and this magnetic field is produced by electrical windings designated at 22 and 23 (see Fig. 2), these windings being wound around laminated iron cores or pole pieces 24 and 25 on opposite sides of the tanks. The windings 22 and 23 are within housings 26 and 27, and they may be cooled by a frame structures 31, 32, and 33 which extend inwardly from the faceplate ii, the frames 31 and 32 supporting insulating members 34 and 35 from which extend inturn supports the upper part of the liner structure 30 as seen on Fig. 1, there being tween frames 49 and 42.

Extending between the frames 31 and 32 is a transverse brace or support member having uprights or supporting members 46 and 47, and between these memstructure 3h, that is, from the frame structure 40, are throat-like portions 5'6 and 57 which also have slit-like entrance openings therein as may be seen in the portion 57, which are aligned with their respective accelerating electrodes and their respective exit openings in the ion source units.

Referring now more particularly to Figs. 3 and 4 which are enlarged views of the ion source units (Fig. 4 showing just one unit), and the manner of adjusting them relative to the accelerating electrodes, it will be seen that the ion source unit which is shown in cross section on Fig. 3 comprises a chamber or outer casing which converges near the upper part and has a smaller upper portion or chamber 61 which has the exit opening 62 therein which is in the form of a longitudinal slit, the chamber being shown in side elevation in Fig. Within the chamber 60 there is a container 63 for the material the isotopes of which it is desired to separate or segregate and this container communicates with the smaller upper chamber by a throat or chimney 64, the lower end of which forms a horizontal baffle as shown within the container 63. The chamber 60 has trunnions at its ends near the upper part thereof as designated at 65 on Fig. 4 and as may be seen in connection with the ion source unit 49 on Figs. 1 and 3. These trunnions ar journalled in bearings formed in the supporting structure 43, as shown on Fig. 4. The bottom of the chamber 69 has attached thereto a bracket 70 by screws 71 as shown having a downwardly extending arm 72 which extends through an opening 73 in the transverse structure 45. Pivotally connected to this arm by a pivot pin 74 is a link 75 the parts being held in assembled relationship by a cotter pin as shown. The link '7 5 is in a generally horizontal position and its other end is pivoted to one arm of a bell crank lever 76 by means of a pivot pin '77 secured by a cotter pin as shown. The bell crank lever 76 is pivotally supported on a fixed bracket 78 by pin 79 and has a slot therein in which engages a pin 81 which connects the bell crank lever to the upper end of an operating stem 82 which extends through a sealing device 83 in the faceplate U. to the exterior of the tank 10 so that the operating stem 82 forms a push rod which may be operated from outside tank 10. From the foregoing it will be observed that by operating a stem or push rod 32, that is, by reciprocating it, bell crank lever 76 is rotated on pivot 79 and its arm which extends upwardly acting through the link 75 moves the arm 72 back and forth to thereby tilt the chamber 60, that is, to rotate the chamber 60 on its trunnions.

The ion source unit 49 has an adjusting mechanism operable from outside of the tank 10 similar to the mechanism just described for the ion source 50, and its parts are similarly numbered with primed numbers.

The ionization is produced in the ion source units by bombarding vapor in the chamber 61 with electrons emitted from a cathode or other electron emissive device. The material of which it is desired to separate the isotopes is placed in the container 63, referring to the ion source 50, and it is heated and vaporized therein by means of electrical heating elements not shown. The vapor passes up into the chimney 64 and into the small chamber 61, and it is ionized in this chamber and then passes upwardly through the slit 62. The ionization is produced by an electron emissive cathode which emits electrons into the chamber 61 and along the length thereof, the cathode being located at one end of the chamber 61; the cathode is designated by the numeral 85 on Fig. 3, it having a back plate or shield beyond it from the chamber 61, and its leads are designated by the numerals S6 and 87. The chamber 61 may have an opening of suitable size for the admission of electrons emitted by cathode S5. The leads pass through a tubular shield 88 which may extend through a sealing device in the faceplate 11 (not shown). Thus, the cathode 85 is ordinarily supported from the faceplate 11 so that when the ion source units are adjusted, the cathode remains stationary not being adjusted with them. The electrons emitted from the cathode form an are which is struck within the chamber 61, and this are is sustained by a voltage which is impressed between the cathode 85 and the ion source unit, the ion source units as a whole being at ground potential as shown on Fig. 1 and serving as an anode. The accelerating electrodes 51 and 52 are maintained at a relatively high negative potential, that is, negative relative to the ion source units by electrical connection, not shown. The entire liner structure 30 and the throats 56 and 57 are also maintained at a rela tively high negative potential, but which is lower than the potential of the accelerating electrodes 51 and 52. The wiring connections for maintaining the potentials of the liner and the accelerating electrodes may be lead in through a conduit 90 as shown on Fig. l which passes through a sealing bushing 91 in the faceplate 11.

Referring to Fig. l, at the upper end of the liner structure 3t) are shown receivers or collectors 93 and 94 in which the charged particles constituting the segregated isotopes are received through openings in the upper parts of the collectors. The charged particles impinge upon electrodes within the receivers and form a deposit upon these electrodes which constitutes the material which it is desired to collect and which may be recovered by subjecting the electrodes to various washing and chemical processes. The receiver 94 is adjustably attached to the receiver 93 by a member 95 and it may be adjusted from outside of the tank 10 by a stem 96 passing through a sealing device 97. The receiver 93 may be similarly adjusted by a stem 98. Further description of the details of the receivers is not necessary since they in themselves form no part of our invention, and they are described in greater detail in the earlier applications referred to above.

in the operation of the system, vapor is formed in the container 63 referring to Fig. 3, and passes upwardly, that is, to the left on Fig. 1 into the chamber 61 and through the exit slit in the ion source unit, and charged particles, that is positive ions, are attracted by the accelerating electrode 52, and accelerated through the throat 57 which is, of course, in the magnetic field. The charged particles are influenced by the magnetic field to travel in arcs of a circle around through the liner structure 30, the radius of the arcs being dependent upon the nuclear mass of the charged particles, and the particles of different nuclear mass coming to a focus at spaced points at the receiver 94 and being received in or on electrodes properly spaced apart to receive the desired isotopes. it is known that in order to achieve the most effective resolution, that is, to most effectively segregate and collect desired isotopes, the accelerating electrode should be offset laterally slightly from the exit slit in the ion source unit. Our invention provides for adjusting the amount of the offset during operation by tilting the ion source units on their trunnions as described above and this may be done individually by operating the individual push rods 32 and 82 from outside the tank 10 in the manner described. It will be observed, of course, that by operating the push rods and thus tilting the ion source units on their trunnions, the upper end, that is, the exit end of the ion source units may be accurately adjusted to vary the lateral offset between the exit slit and the acceierating electrodes. This manner of adjusting the olfset eliminates any need for making adjustments in the mountings of the accelerating electrodes themselves, and there is thus no danger of disturbing the setting of the gap, that is, the spacing between the electrode and the exit slit in the ion source unit. Since the ion source units themselves are maintained at ground potential, the difiiculty of manually adjusting any element at a high potential is obviated, and thus insulating and protective mechanisms for this purpose are made unnecessary.

From the foregoing those skilled in the art will observe that we have provided an efficient and effective means for manually adjusting the offset of the accelerating electrode in calutrons during operation of the calutron. In this manner during operation the most effective conditions for obtaining maximum resolution and optimum production of isotopic material may be secured.

The embodiment of my invention disclosed herein is representative of its preferred form. The disclosure is to be interpreted in an illustrative rather than a limiting sense, the scope of the invention being determined in accordance with the claims appended hereto.

We claim:

1. In a calutron, an evacuated tank, an ion source disposed within said tank and having an elongated exit slot at one end thereof for the emergence of ions therefrom, an accelerating electrode having an elongated slot therein, means for fixedly mounting said electrode within said tank in a position adjacent said one end of said ion source with the slot of said electrode substantially aligned with the for controlling from a point exterior to the tank the angular position of said source about its pivot axis.

2. Apparatus, as claimed in claim 1, wherein said last said slots, and a linkage mechanism connected at one end to the inner end of said rod and at the other end to said ion source.

4. Apparatus, as claimed in claim 3, wherein said linkage mechanism comprises a bell crank lever and a link, said bell crank lever having its apex pivotally connected to a fixed point, its one leg pivotally connected to the inner end of said rod, and its other leg pivotally connected to one end of said link, said link having its other end pivotally connectcd to said ion source.

2,221,467 Bleakney Nov. 12, 1940

Claims (1)

1. IN A CALUTRON, AN EVACUATED TANK, AN ION SOURCE DISPOSED WITHIN SAID TANK AND HAVING AN ELONGATED EXIT SLOT AT ONE END THEREOF FOR THE EMERGENCE OF IONS THEREFROM, AN ACCELERATING ELECTRODE HAVING AN ELONGATED SLOT THEREIN, MEANS FOR FIXEDLY MOUNTING SAID ELECTRODE WITHIN SAID TANK IN A POSITION ADJACENT SAID ONE END OF SAID ION SOURCE WITH THE SLOT OF SAID ELECTRODE SUBSTANTIALLY ALIGNED WITH THE SLOT OF SAID ION SOURCE, MEANS FOR PIVOTALLY MOUNTING SAID ION SOURCE FOR ANGULAR ROTATION ABOUT A FIXED PIVOT AXIS, SAID PIVOT AXIS BEING ALIGNED WITH AND IN CLOSE PROXIMITY TO THE SLOT OF SAID ION SOURCE, AND MANUALLY OPERABLY MEANS FOR CONTROLLING FROM A POINT EXTERIOR TO THE TANK THE ANGULAR POSITION OF SAID SOURCE ABOUT ITS PIVOT AXIS.

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