US3348040A

US3348040A - Atomic beam tube apparatus with transverse headers and spacers to position the components in the housing

Info

Publication number: US3348040A
Application number: US385202A
Authority: US
Inventors: Robert F C Vessot
Original assignee: Hewlett Packard Co
Current assignee: HP Inc
Priority date: 1964-07-27
Filing date: 1964-07-27
Publication date: 1967-10-17
Anticipated expiration: 1984-10-17
Also published as: GB1112234A; US3422456A; DE1491531A1

Description

Oct. 17, 1967 I R. F. c. VESSOT 3,343,040

ATOMIC BEAM TUBE APPARATUS WITH TRANSVERSE HEADERS AND SPACERS TO POSITION THE COMPONENTS IN THE HOUSING Filed July 2 1964 2 Sheets-Sheet 1 an fx PRIIOR AR? INVENTOR. ROBERT F C. VESSQT ATTORNEY Oct. 17, 1967 F. c. VESSOT 3,343,049

ATOMIC BEAM TUBE APPARATUS WITH TRANSVERSE HEADERS AND SPACERS TO POSITION THE COMPONENTS Y IN THE HOUSING Filed July 27. 1964 2 Sheets-Sheet 2 INVENTOR. ROBERT E C. VESSOT ATTORNEY United States Patent ABSTRACT OF THE DISCLOSURE An atomic beam tube with a circular electric mode C- field resonator. The elements of the tube are cylindrical and mounted around a common-axis. Annular headers provide a self-jigging construction.

The present invention relates in general to atomic beam tubes and more particularly to an improved atomic beam tube utilizing a novel circular electric mode C-field resonator and/ or a cylindrical self-jigging construction whereby improved frequency stability is obtained and ease of fabrication facilitated. Such improved atomic beam tubes are useful, for example, as atomic clocks and as frequency standards.

Heretofore atomic beam tubes have employed the conventional Y-shaped C-field resonator formed of rec-.

tangular waveguide to provide a pair of axially spaced beam-field interaction regions for exciting resonance of the atomic beam particles. A recent improvement in these cavities. involved feeding the RF. energy to the cavity through a low Q section and is described and claimed in U.S.' patent application Ser. No. 340,767 titled, .Improved Cavity Resonator for Atomic Resonant Devices, filed Ian. 28, 1964, inventors Joseph H. Holloway-ct al.,

T0 POSITION,

circular electric cavity in this combination has many advantages over the prior rectangular cavityresonator. For instance, the circular electric mode'resonator allows use j of larger sized beam holes inthe cavity'structure without as much coupling tothe dominant mode and thus with, out producing as much phase shift in the RF. fields taken across the beam in the beam field interaction region. Therefore, the transverse phase shift is greatly reduced, leading to frequency stability which is in excess of 1 part. in 10 for cesium and leads to evengreater-enhance-Q ment in stability of thallium beam tubes. In addition, the.. circular electric mode resonator, when axially aligned with thebeam, path, lends itself especially well to use. with quadrupole state-selecting ,beam focusing "magnets, thereby permitting use of a higher number magnetic. poles leading to beams of higher flux density. Furthermore, be-. cause of the extremely low loss of the circular electric mode as compared to other modes, the undesired phase. shift of the RP. fields from one beamrfieldinteraction. region to the next due to absorption of energy in the side walls of the resonant structure is minimized, thus leading.

to enhanced frequency stability.

In another embodiment of the present invention.trans-'..

verse alignment of the various tube elements is readily obtained by a tube construction wherein the tube elements I are supported from transverse headers inserted within a... self-jigging cylindrical barrel support member. Longi-.- 'tupdinal alignment is readily achieved by.the provision.

. of spacer members inserted between the transverse headand assigned to the same assignee as the present invention.

smaller dimensions of the rectangular guide for thallium relative to the" transverse beam dimension. Inaddition, the local phase shifts produced by leakage of power out of the beam hole 'in the. rectangular guide'cavity is a significant phase shift factor and in the case of thallium again creates a more severe limitation on maximum ob-,

tainable frequency stability because the beam hole is of relatively larger size.

Another problem encountered with the prior atomic beam tubes is that they have employed a rigid longi-.

tudinal beam or channel member upon which the various tube elements are supported. While this type of construction provides sufiicient rigidity it makes transverse align- One of the problems encountered in the prior rec-' ment of the tube elements difiicult because of the lack of a pair of orthogonal aligning surfaces. Also, suspension of the supporting channel member presents certain difliculties in order to prevent introduction ,of stresses which would interfere with proper transverse alignment of the parts with the beam over the elongated beam path. Such a prior channel support structure is described and claimed in US. patent application No. 233,573 titled Atomic Beam Apparatus filed Oct. 29, 1962, inventor Joseph H. Holloway et al., now issued as US. Patent 3,323,008 and assigned to the same assignee as the present invention.

ers. The barrel support, in a preferred embodiment, also serves .as the vacuum envelope and is sealedat one end by a vacuum-tight electrical. socket or insulated feed-- through assembly.

The principal object of the provision of an improved atomic beam tube.

One feature of the'present inventionis the provision. of a circular electric mode C-field resonator structure 2 whereby undesired phase shifts in the applied 'R.F. fields in the beam-field interaction regions are minimized and frequency stability of the atomic beam tube apparatus is enhanced.

Another feature is the same as the precedingfeature v wherein the circular electric mode resonator is axially with the beam axis and a quadrupole 'or higher even numbered pole state selecting beam focusing magnet is used, whereby the atomic beam density is increased and p frequency stability enhanced.

Another feature of the present invention is the proi vision of an atomic beam tube construction employing a barrel-shaped tube element supporting structure with a plurality of axially spaced self-jigging transverse header members mounted therein, said header member carrying therefrom the various tube elements whereby tube construction and alignment is greatly facilitated.

Other features and advantages of the present invention will become apparent upon a perusal of the following specification taken in connection with the accompanying drawings wherein:

a FIG. 1 is a longitudinal sectional view of an atomic: beam tube employing the features of the present invention;

FIG. 2 isfa line diagram showing the transverse magnetic field phase shift variation over the beam for the prior art rectangular C-field cavity resonator;

i FIG. '3 is a line diagram showing the transverse R.F.i

magnetic field phase shift variation over the beam for the circular electric mode C-field cavity resonator of the pres ent invention; p

Patented Oct. 17, 1967 present invention isthe 4 isan'enlar ged alongitudinal sectional view of a preferred C-.field cavity embodying features of the present invention;

FIG. 5 is a fragmentary perspective view of a portion of ,the structure of FIG. 4-delineated by line 55;

' ent invention. ,More specifically the atomic beam tube includes an elongated-combined tubular envelope andhollow cylindrical shaped support structure 2 as oIfn'on-magnetic stainless steel. The novel tube construction will be more fully described below. Contained within fhe'envelope 2 is a source 3 of atomic beam particles such as, for example, cesium or thalium atoms which pro'jectsthe beam particles axially of the tube structure over an elongated beam path 4. A beam particle detector 5 such as a conventional hot wire ionizer is disposed .at the terminal end of .theb'eam path for detectingresonance of the beam.

A circular electric C-field cavity resonator 6 is disposed midway between the beam source 3 and detector 5 for exciting atomic resonance of the beam particles by an alternating magnetic field component H in the presence of a DC. polarizing magnetic 'C-field component H When the atomic beam tube is being used as a frequency standard or *atomic cloc the beam particles are preferably resonated in a field independent transition or resonance and for this condition the alternating R.-F. magnetic field H at the atomic resonance frequency should have a strong component parallel to a DC. polarizing magnetic field-component H commonly called the C-field.

A particularly advantageous combination of C-field magnet and .C-field cavity resonator structure '6 is obtained when the circular electric mode resonator '6 is used with a cylindrical magnetically shielded C-field solenoid 7 ,for producing the axially directed polarizing C-field H along the beam path within the resonator 6. The cylindrical solenoid 7 yields a very uniform polarizing magnetic C-field and is described and claimed in my copending U.S. patent application Ser. No. 366,493 titled Atomic Resonance Method and Apparatus With Improved Magnetic Field Homogeneity Control filed May 1 l, 1964, inventor RobertF. -C. Vessot, and assigned to the same assignee as the present invention.

The'circular electric mode resonator structure 6 comprises a pair of axially spaced-apart cylindrical resonator chambers 8 coaxially aligned with the beam path 4. Each cylindrical resonator 8 is provided with a pair of apertures 9 the end walls -in registry with the beam path 4 to permit passage of the 'beam theret-hrough. An axially directed section of rectangular waveguide 11 interconnects the two cylindrical chambers 8 and is coupled to each chamber 8 via the intermediary of 'ir-ises 12, see FIG. 3.

Wave energy is fed into the rectangular waveguide 11, at a point preferably midway of its length, via the intermediary of a suitable coupling device, such as a conventional magnetic coupling loop 13, which is excited by a coaxial line-'14. The rectangular section of guide '11 preferably has high Q as taught in the first aforementioned ap-' plication Ser. No. 340,767. In addition, the coaxial line includes a high loss section 15 and a reflective discontinuity 16 disposed between the high loss section and a source of microwave energy, not shown, at the atomic resonance frequency connected at terminal 17 of the coaxial line 114. C-field resonator 6 structure is defined by the composite coupled coaxial line sections, 15, 16 waveguide 11, and cylindrical chambers .8. The cylindrical chambers '8 are dimensioned to support a dominant circularelectric- TE mode at the atomic resonance frequency when ex-.

cited with wave energy coupled through irises 12. The resonant section of transmission line or waveguidelh magnetic field across the beam, transverse phase and coupled chambers 8 define a high Q portion of the vcomposite resonator structure .6. The low .Q portion in cludes the high loss section 15 of coaxial line 14 intermediate the coupling loop 13 and the reflective discon: tinuity to thereby provide a low Q composite resonator to prevent thermal detuning-eifects while at the same time providing a high .Q portion to prevent undesired phase. shifts between'the magnetic "fields in the spaced .charn-.

. bers 8 due to energy absorption in the high Q portion, as; I taught in the aforementioned application 'Ser. No. 340,767.

The mounting of the shielded solenoid '7 and cavity structure 6 is more fully described below with .regard'to a preferred embodiment of the present invention shown in FIG. 4. r

A Pair of magnetically shielded state selecting magnets l 18 and 19 are disposed .on opposite ends .of .the resonator structure 6, respectively. -In a preferred embodiment,

magnets 18and 19 are quadrupole orhexapole magnets to obtain a focusing of the beam as wellas state selectioml Magnet 18 is disposedbetween the source 3 and the resonator 6. Magnet 18 focuses out of the beam atomic particles of one energy state and focuses intoward the center of the beam particles of the other energystate. Either state may be selected for the beam by merely intercepting the unwanted beam particles. However, by selecting the atomic energy state which .is focused in toward thecen ter of :the beam an additional advantage is obtained due to' the increased beam density yielding smaller beam crosssectional areas for a given beam flux intensity. Smaller beam cross-sectional area leads ;to smaller transverse phase shifts in the applied RJF. resonating magnetic field 1 H in the beam-field interaction regions .and thereby yields greater frequency stability of the tube.

The :spaced resonator chambers 8 provide .the axially spaced beam-field interaction regions for resonating the atomic beam particles. The resonant fields H in :the spaced chambers .8, at atomic resonance ofthebeam, the particles out of phase*oper,ation, depending upon whether a ring detector of axially disposed button detector is used and also depending upon whether peak or null detection :is desired.

In the apparatus shown, for in phase? operation of chambers 8, at atomic resonance of the beam, the particles will .be deflected out of the beam :by the .second state selecting magnet 19. Thus, resonance of the beam will appear as a null in the :detected beam current of detector 5 when using a button detector ,5 and a peak amplitude signal will :appear when using a ring or annular detector. If the phase of the RF. fields in chambers 8 is 180 out of phase (out of phase operation) .then,wi,th the button detector apparatus shown, at resonance there would be a peak in amplitude of the detected beam currentlat button detector :5 and a null or minimum if an annular detector were utilized instead .of the "button detector.

The circular electric mode resonator structure 6 allows substantially less transverse phase shift in the applied R.F.

magnetic field 4 across the beam as compared :to the phase shift is illustrated in FIGS. 12 and 3. More .7

specifically FIGXZ shows the conventional rectangular waveguide and beam hole wherein the beam is directed across the guide from one broad wall to the other near the shorting end Wall of the cavity. Phase shift is produced by flow ofpower to the lossy side walls of the cavity from the reflected wave. Thus, the phase shift increases in the direction of' travel of the reflected wave away from the shorting wall. This produces a phase shift'in the RF.

shift. One might think this phase shift could be reduced. by orienting-the beam hole such that it were elongated parallel to the: shorting wall such that the transverse.

to flow around the slot and thereby couples wave energy.

out through the beam hole and produces even greater phase shift.

' Referring now to FIG. 3 there is shown a similar diagram to that of FIG. 2 showing the beam field interaction region and phase shift for a circular electric mode resonator chamber 8 and coaxial beam hole and trajectory. In this instance the reflected wave travels axially of the chamber 8 and power loss in the side walls of the chamber is less because the circular electric mode has the least power loss of any mode and certainly less than the rectangular waveguide mode. Furthermore, note that the phase shift is constant in any one of the transverse planes of the cavity, such that the transverse phase shift across the beam is negligible. What phase shift there is is longitudinal and it turns out that if this phase shift is equal in both chambers 8 and the chambers are symmetrical about a transverse plane midway between the'chambers thatthe longitudinal phase shift will cancel out. Also the beam holes do not significantly perturb the cavity circulating currents, since the currents are at a minimum in the end walls on the axis of the resonator chamber 8, as indicated, and circulate around the beam hole rather than tending to flow across the holes. 1

In addition, the circular electric mode resonator is approximately twice the diameter of the rectangular guide and can therefore tolerate a beam hole of approximately twice the size of the rectangular cavity for the same perturbation. The circular electric mode resonator chamber 8 is especially well suited for a thallium beam tube since the resonant frequency for thallium is about twice that of cesium and therefore the rectangular cavity would be about half the size of the cesium cavity.

Referring now to FIG. 4, there is shown a preferred circular electric mode cavity resonator structure 6 in corporating features of the present invention. The circular electric mode cavity in this instance is defined by a quartz cylinder 22 coaxially disposed of the beam path 4. The cylinder is coated on the inside with a coating of low-loss conducting material, such as silver, with a thickness of a few skin depths at the atomic resonance frequency. The end walls 23 of the cavity '6 are formed by conductive plates, as of aluminum, afiixed to the ends of the quartz cylinder 22 via the intermediary of flexible cylindrical segments 24, as of thin gauge BeCu. Annular recesses 25 are provided between the end wall and the cavity side wall to attenuate undesired TM modes that might couple to or interfere with the desired mode. a

A small diameter hollow dielectric tube 26, as of quartz, is coaxially disposed of the cylinder 22 and is coated at 27 over apreponderance of its length on the exterior surface with a conductive material, such as silver, to produce an RF. field free region 28 within the interior of the tube 26. The conductive coating is terminated short of the endwalls 23 at 29, such that the space remaining between points 29 and the end walls 23 is dimensioned of sufficient length to support the TE circular electric mode and permit the RF. magnetic fields of this mode to extend into the beam path 4 in this region of the cavity structure 6, thereby defining the pair of axially spaced beam-field interaction regions 8. Regions 8 are coupled together by a resonant section of coaxial transmission line 31 operating in a circular electric mode of the TE configuration, where n is greater than 1.

Wave energy is coupled into the circular electric mode resonator structure 6 via the intermediary of a shallow height section of arcuate rectangular waveguide 32 (See FIG. formed by conductive channel housing member 33 strapped in electrical contact with the outer silvered surface of the quartz cylinder 22. A pair of conductive end walls 34 short the opposite ends of the rectangular waveguide 32. An axially-directed elongated coupling iris 35 is cut through and conductively plated through the Wall of the cylinder 22 for coupling to the circular electric mode of the resonator 6 at a central point of symmetry. A similar iris 36 is cut through one of the end walls 34 of the rectangular waveguide 32. A short arcuate section of waveguide 37 interconnects the two irises and 36 for heavily coupling wave energy therebetween.

A pair of inductive vane members 38 produce a strong reflective discontinuity in the waveguide 32 and define a coupling iris 39 therebetween and thus also define the outerterminal boundary of the feed arm portion of the cavity resonator structure 6. A resistor card 41 is disposed across the feed arm portion of the guide 32 fom one broad wallto the other to heavily load the composite cavity resonator 6 defined by the feed arm portion and the high- Q circular

electric mode portions

31 and 8 to lower the composite Q of the entire resonator structure -6 without introducing loss into the high Q portion, thereby rendering the entire cavity relatively insensitive to thermal detuning effects according to the teachings of the. aforementioned V patent application Ser. No. 340,767. Wave energy is coupled into the feed arm waveguide 32 via a coaxial line 42 and inductive coupling loop 43. The coaxial line 42 is directed axially of the tube'and is connected to a source of microwave power at the frequency of the atomic beam resonance disposed externally of the tube 1. V

The cylindrical magnetically-shielded solenoid 7 (see FIG. 4) coaxially surrounds the cavity 6 and includes a cylindrical coil form 44, as of aluminum, grooved on the outer surface and anodized to form an insulative coating to receive multiple turns of aluminum wire 45 formingthe C-field solenoid 7. A cylindrical magnetic shield member 46, as of a material sold by the Allegheny Ludlum Steel Corp. under the trademark Moly Permaloy, coaxially surrounds the solenoid 7 to shield the interior of the solenoid from extraneously produced magnetic fields including-the earths field. A pair of centrally apertured annular. magnetically permeable end Walls 47 close off the ends of the cylindrical portion 46 of the solenoid shield. An outer cylindrical magnetically permeable solenoid shield 48 coaxially surrounds the inner shieldand likewise includes centrally apertured annular magnetically permeable end closing walls 49. V

Referring now to FIGS.,1, 4, .6 and 7, circular electric mode cavity structure 6 and the associated .solenoid 7 and magnetic shields are all supported within the combined cylindrical vacuum envelope 2 and support structure in a self-jiggingmanner such as to readily achieve and main-. tain proper transverse alignment of the cavity structure 6 in the followingv manner: The cylindrical outer. 1'nag netic shield 48 is formed by a rolled sheet of metal and includes merely an overlappingslidable. abutment of the axial marginal edge portions of the outwardly tensioned cylinder 48. In this manner the .cylinder 48 is free to expand out against theinner jiggingsurface of the inner bore of the cylindrical envelope 2, as of precision bore non-magnetic stainless steel tubing. A pair of annularheaders 51, as of stainless steel, jig to the inside surface, of the cylindrical envelope 2 via the. intermediary of the end port-ions of the outer cylindrical shield 48 and are aflixedthereto via a plurality of circumferentially spaced sheet metal screws 52 threaded through av plurality of inwardly directed tabs 53. The screws also hold the end walls 49 of the shield to the side walls ofthe outer shield 48 via the tabs 53. v A 'The inner magnetic shield 46 isindexed at itsends to the annular header 51 via the intermediary of a pair of convoluted annular spacers 54, as of stainless steel. The spacers 54 are welded to .the first header 51 and bear in longitudinal and transverse engagement against a pair of oppositely convoluted portions 55 of'the annular end walls 47 of the inner shield 46. I g The cavity resonator structure 6 is indexed to and sup portedfrom the ends of the inner magnetic shields 47 via the intermediary of a pair of double-convoluted annular spacers 56, as of aluminum. The annular spacers 56 index to transverse aligning

interfaces

57 and 58 on the shield end walls 47 and cavity end walls 23, respectively. The center tube 26 for the cavity is supported from 7 and indexed to the cavity end walls 23 via the intermediary of apair of annular headers 59. The headers 59 axial- 1y receive the tube 26 and capture same therebetween by beating in longitudinal engagement against a pair of 'quartz washers .61 carried on the tube '26. i

The shielded cavity structure is fixedly secured against .axial movement to the envelope 2 substantially only at one end by having the outer magnetic shield 48 'fixed in the axial direction against stops 62 spot-welded to the inside wall ofthe envelope 2 and to the shield 48. A helical spring '63 as of 'BeCu is captured at one end against the inside surface of the magnetic shield end'wall 47 and a transverse corrugated header 65, as of aluminum, which provides transverse alignment but which will allow relative axial movement between the cavity 6 and the coil form 44.

The above-described self-jigging tube construction is especially advantageous because the tube is made up of parts having greatly diiferent coeflicients of thermal expansion and after assembly the tube is evacuated and baked at 400 C. to fully outgas all parts. During the bakeout cycle the quartz cavity cylindrical side wall 22 expands radially approximately 0.00 While the coil form 44 expands radially approximately 0.130". Similarly, even greater differential expansions are obtained in the axial direction. Proper transverse alignment to approximately 0.001 .is required to be maintained after the bakeout cycle over the length of the tube from source 3 to detector 5. The above described self-jigging construction permits the relatively large differential expansion while main- .taining the requisite 'concentricity or transverse alignment.

A similar self-jigging header and spacer support structure is employed for the other elements of the tube structure, (see FIGS. 1, 6 and 7.) such as the source 3, state selecting magnets '18 .and 19, and detector 5. While longitudinal spacing of the elements is not nearly so critical as transverse alignment, proper longitudinal spacing is advantageously obtained by use of spacer ring members 66 or rods, not "shown, stacked in between successive selfjigging transverse headers 67. The entire stack of elements is then preferably spring-loaded in compression by a crenelated ring spring 68 disposed in between the stack of .elements and an end closing wall 69 of the envelope '2 which forces the elements down into the support barrel against a suitable stop such as shoulder 70. Note, that if shoulder 70 is used, then stop 62 is eliminated. The end closing wall 69 includes a lip portion 71 which abuts the envelope '2 at its open end'and is joined and .sealed thereto as by a Weld 72 running around the lip portion 71 at 72.

The end closing wall 69 includes a plurality of hermetically sealed feedthrough insulator assemblies 73 for bringing in and out the electrical connections for the various signals and potentials to various elements within the tube. In addition, the end closing wall includes a pinched-01f exhaust tubulation 74 for exhausting the tube during processing. Moreover, the various transverse headers within the stack of assembled elements are perforated at 75 to facilitate exhausting of the tube 1 during processing. The tube is pumped in use by means of a conventional getter ion pump assembly 76 (not sectioned) disposed within the stack of elements. Aligning pins 77 passing axially through aligned openings in the transverse headers 67 and spacer rings 66 and serve to prevent torsional displacement of the variousparts'relative to each other.

i The atomic resonance tube apparatus, previously :described, is not limited to cesium or hydrogenatoms alone. Certain'other isotopes of other metals such as, for example, thallium, and rubidium may be used. Any electron re-orientation transition or responance in atoms or molemiles for .which the net at'oms or moleculesangular momentum, f, is an integer .in quantum units of Planks constant, It, may be used. In general, it iscontemplated any suitable molecular or atomic beam or assemblange having desired resonance characteristics may be used. The terms atom or atomic particle as used herein'is defined to mean molecules as well as atoms.

Since many changes could be made in the above construction and many apparently widely dilferent embodiments of this invention could be made without departing frornthe scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. What is claimed is:

1. An atomic beam jtube apparatus including means forming a source of beam particles for forming and projecting a beam of atomic particles over a predetermined elongated beam path, means forming a detector disposed along the beam path for detecting resonance of the beam particles, means forming a pair of state selector magnets disposed along the beam path for deflecting the beam particles and selecting their energy states, means 'for applying microwave radiation to the beam between said pair of state selector magnets for producing resonance of the beam particles, means forming an elongated tubular support structure surrounding all of said aforementioned means for supporting same, and means forming a plurality of transverse headers, all of said supported means being operatively supported from and deriving their axial alignment from said tubular support means via the intermediary of said header means, a plurality of said header means being axially movable relative to said tubular support means to accommodate differential axial expansion therebetween and to facilitate assembly of the 'tubeapp'aratus, and means forming a plurality of spacer members disposed between adjacent transverse header means for determining the proper axial spacing of said supported means within the tube apparatus.

2. The apparatus according to claim 1 including means forming a spring producing an axially directed force holding together said supported means and assuring proper longitudinal spacing thereof.

3. The apparatus according to claim 2 including means tor means mounted therein for feeding different electric potentials to various means within the tube apparatus.

4. The apparatus according to claim 1 wherein a plurality of said header means bear in slidable engagement at their outer periphery with the inside bore of said tubularsupport means for axially aligning said supported means within the tube apparatus.

References Cited UNITED STATES PATENTS 2,879,439 3/ 1959 Townes 33194 X 2,972,115 2/ 1961 Zacharias et a1. 331-3 3,'()60,3 10/1962 LippS et -al. 331-3 3,255,423 6/1966 Ramsey et al. 33-194 WILLIAM F. LINDQUIST, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,548,040 October 17, 1967 Robert F. C. Vessot It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 37, strike out "at atomic resonance of the beam, the particles" and insert instead may be selected for "in phase" operation or Signed and sealed this 22nd day of October 1968.

(SEAL) Attest:

Edward M. Fletcher, Jr. EDWARD BRENNER Attesting Officer Commissioner of Patents

Claims

1. AN ATOMIC BEAM TUBE APPARATUS INCLUDING MEANS FORMING A SOURCE OF BEAM PARTICLES FOR FORMING AND PROJECTING A BEAM OF ATOMIC PARTICLES OVER A PREDETERMINED ELONGATED BEAM PATH, MEANS FORMING A DETECTOR DISPOSED ALONG THE BEAM PATH FOR DETECTING RESONANCE OF THE BEAM PARTICLES, MEANS FORMING A PAIR OF STATE SELECTOR MAGNETS DISPOSED ALONG THE BEAM PATH FOR DEFLECTING THE BEAM PARTICLES AND SELECTING THEIR ENERGY STATES, MEANS FOR APPLYING MICROWAVE RADIATION TO THE BEAM BETWEEN SAID PAIR OF STATE SELECTOR MAGNETS FOR PRODUCING RESONANCE OF THE BEAM PARTICLES, MEANS FORMING AN ELONGATED TUBULAR SUPPORT STRUCTURE SURROUNDING ALL OF SAID AFOREMENTIONED MEANS FOR SUPPORTING SAME, AND MEANS FORMING A PLURALITY OF TRANSVERSE HEADERS, ALL OF SAID SUPPORTED MEANS BEING OPERATIVELY SUPPORTED FROM AND DERIVING THEIR AXIAL ALIGNMENT FROM SAID TUBULAR SUPPORT MEANS VIA THE INTERMEDIARY OF SAID HEADER MEANS, A PLURALITY OF SAID HEADER MEANS BEING AXIALLY MOVABLE RELATIVE TO SAID TUBULAR SUPPORT MEANS TO ACCOMODATE DIFFERENTIAL AXIAL EXPANSION THEREBETWEEN AND TO FACILITATE ASSEMBLY OF THE TUBE APPARATUS, AND MEANS FORMING A PLURALITY OF SPACER MEMBERS DISPOSED BETWEEN ADJACENT TRANSVERSE HEADER MEANS FOR DETERMINING THE PROPER AXIAL SPACING OF SAID SUPPORTED MEANS WITHIN THE TUBE APPARATUS.