US3376414A - Calutron with means to direct calcium gettering vapor into the ion beam to reduce tank pressure - Google Patents

Calutron with means to direct calcium gettering vapor into the ion beam to reduce tank pressure Download PDF

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Publication number
US3376414A
US3376414A US461568A US46156865A US3376414A US 3376414 A US3376414 A US 3376414A US 461568 A US461568 A US 461568A US 46156865 A US46156865 A US 46156865A US 3376414 A US3376414 A US 3376414A
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United States
Prior art keywords
calcium
vapor
calutron
ion beam
ion
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US461568A
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English (en)
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Jr William A Bell
King A Spainhour
Allen M Veach
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US Atomic Energy Commission (AEC)
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Atomic Energy Commission Usa
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Priority to US461568A priority Critical patent/US3376414A/en
Priority to GB19169/66A priority patent/GB1114663A/en
Priority to SE7701/66A priority patent/SE318733B/xx
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/26—Mass spectrometers or separator tubes
    • H01J49/28—Static spectrometers
    • H01J49/30—Static spectrometers using magnetic analysers, e.g. Dempster spectrometer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/04—Arrangements for introducing or extracting samples to be analysed, e.g. vacuum locks; Arrangements for external adjustment of electron- or ion-optical components

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  • ABSTRACT 0F THE DISCLOSURE A calcium boiler is positioned within the tank unit of a calutron such that the calcium vapor from the boiler is directed toward the calutron ion beam and the vapor encompasses the greater portion of the ion beam.
  • the gettering action of the calcium helps to further reduce the calutron tank pressure.
  • the ion outputs for most isotopes, which are separated during use of the calcium boiler are increased by at least tenfold over what was expected on the basis of improved vacuum alone, and ion beam resolutions are also greatly improved.
  • Vapor from the vaporizer or oven passes to an arc chamber where a stream of electrons (commonly called the arc discharge) is passed through these vapors, ionizing them for subsequent acceleration through a magnetic field.
  • a stream of electrons commonly called the arc discharge
  • One means for heating the charge material for use in the ion source is dis closed in US. Patent No. 3,115,575 to William A. Bell, et al., issued Dec. 24, 1963.
  • FIG. 1 is a schematic diagram of a calutron unit provided with a calcium boiler
  • FIG. 2 is a cross-sectional view of the calcium boiler of FIG. 1.
  • the above objects have been accomplished in the present invention by providing a calcium boiler within the tank unit of a calutron positioned in such a manner that the calcium vapor from the boiler is directed toward the ion beam from the ion source unit of the calutron such that the vapor sees the greatest portion of the ion beam' from the ion source.
  • the gettering action of the calcium helps to further reduce .the tank pressure of the calutron.
  • the expected improved operation on the basis of improved vacuum is a l0-20% increase in the ion output for the isotopes of sulfur, for example, while actually an improvement of about 300% in ion output was attained when using the calcium boiler in a calutron. This indicates that factors other than pumping are involved.
  • a conventional. calutron has an ion source 1 and a receiver 2 mounted from faceplates, not shown, and inserted Within a vacuum tank 3.
  • the tan-k 3 is evacuated by means of a vacuum pump, not shown, in a conventional manner.
  • the ion receiver 2 is provided with several collection pockets, not shown, in a conventional manner to receive the separated isotopes as separated by the magnetic field encompassing the tank 3 with the field being provided by means, not shown, in a conventional-manner.
  • the magnetic field may be provided for the unit of FIG. 1 in the same mannet as set forth in the above-mentioned Lawrence patent.
  • a typical ion beam 4 is shown passing through a bafiie assembly 5 positioned midway between the ion source 1 and the receiver 2.
  • the boil-er 7, as shown in detail in FIG. 2, is fabricated in a manner similar to a conventional ion source in that a charge bottle 8 is heated by a first set of heaters 10, and the vapor exit area 22 of the boiler is maintained at a. higher temperature by a second set of separate heaters 18, 18.. No ionization or acceleration is provided.
  • the exit slit 17 of the vapor area 22 is so shaped that the vapor is exited with a cross section having about a 30 included angle.
  • the boiler has a capacity of vaporizing 3-5 grams of calcium per hour, and is normally operated with about 650 watts of power to the first set of heaters and 1100 watts to the second set of heaters. All portions of the boiler which are in contact with the calcium metal or vapor that is, the member 14, the top plate the vapor exit nipple 21 connecting the charge bottle 8 to the area 22, the housing 9 for the charge bottle, and the member which threadedly engages the nipple 21, are fabricated from, or protected by, stainless steel.
  • the remainder of the boiler including the housing 12, the member 23, the lower heater insulators 11, 11 and the upper heater insulators 19, 19', is graphite.
  • Heat shielding 13 is provided in the lower part of the boiler encompassing the charge bottle 8, and heat shieldings 16, 16' are provided about the heaters 18, 18'.
  • the results obtained using the calcium getter pump are better than expected when utilized during the enrichment of S.
  • the feed material for this separation was CS
  • the tank pressure dropped an amount equivalent to the pumping capacity of at least eight 20-inch oil diffusion pumps.
  • the quantity Q in milliamperes of the S ion beam increased by a factor greater than three.
  • the expected or hoped-for improvement of 10-20% in the ion beam output as a result of'the use of the calcium pump was thus surpassed by the greater-than-l00% improvement obtained.
  • the following table shows the eifect upon pressure and the quantity Q, in a typicalrun, Q being the total ion current for all the isotopes collected.
  • the preferred charge material for these separations is SiS and, when the calcium vapor generator is utilized, the average ion current for the Si isotopes is routinely doubledfrom 6O ma. to ma.
  • the average assay for Si was about 94.0% with some assays as high as at least 97%, and the average assay for Si was about 95.0% with some assays as high as at least 97.5% when using the calcium boiler in the calcutron, and these assays represent about a twofold increase in enhancement over that achieved without the calcium boiler.
  • the charge material is a tungsten chloride which may be WCl' or WCI for example.
  • the vacuum was increased from 1X10 torr to 2'.5 10 torr, and the ion current at the receiver was approximately doubled over that achieved without the vapor generator.
  • the enrichment index for W' was increased by a factor ofabout 3, with the assay increased from 94% to 97.6%.
  • the charge material is TiCl and, when the calcium. vapor generator is used, the pressure is substantially reduced and the assays for Ti and Ti were 90.1% and 87.8%, respectively, as compared with 86.4% and 84.1%, respectively, that could be achieved with the calutron operating without the calcium vapor generator.
  • the assay of collected isotopes of mercury is significantly increased when using the calcium vapor generator without liner cooling, and, if the desired assay can be achieved or approached without the alcohol cooling, at saving of the order of hundreds of dollarsv per week can be realized during the separation of desired mercury isotopes including Hg.
  • the increased output using the calcium vapor generator almost compensates for the cost of cooling if such is required.
  • HgS The charge material used for the above mercury. separations was HgS. However, HgCl charge material can also be and has been used to provide operating results that are closely comparable to those obtained with HgS.
  • HgS chargematerial is preferred since it provides for slightly better, resolved ion beamsthan that obtained with the HgCl material when using the calc1um vapor generator.
  • the improvements that are obtained when a calcium vapor generator is utilized, in a calutron, as discussed above, may be summarized as substantially increased ion output, improved ion beam resolution, and/or lowered background pressure, and, as pointed out above, there are improvements in calutron operation for mercury separations that occur even though little change in base pressure is effected.
  • the expected ion beam outputs based upon pressure reduction alone have been substantially exceeded, thus providing a unique and very efficient method for the separation of isotopes with the assays of the collected isotopes being substantially greater than those obtainable with prior art calutrons.
  • the present invention is not limited for use with just the highly volatile compounds as discussed above.
  • the calcium pump will pump most, if not all, of the halide ions, particularly chlorine.
  • S Cl can be and has been used as a feed material for the collection of sulfur isotopes.
  • the calcium pump can be used for most separations involving not only the highly volatile compounds, but also those compounds that have a low vapor pressure.
  • the calcium pump not only reduces the background contamination, but also reduces the background pressure in most separations, it permits the use of more optimum are conditions which provides for even more eificient operation.
  • An additional advantage that accrues from the present invention is the retention of material on the tank walls, due to the formation of compounds with the getter vapor, rather than being removed into the conventional vacuum system. When recycle of material is necessary, this is a very important feature.
  • the deposited vapor may also contribute secondary electrons that assist in space charge neutralization in the ion beam.
  • An improved system for substantially increasing the ion output, providing substantially better ion beam resolution, eliminating any possible need for calutron liner cooling, and for lowering the background pressure in a calutron including a vacuum tank; an ion source and an ion receiver disposed within said tank, said ion source being adapted to receive a charge material; evacuating means connected to said tank; means for providing a magnetic field encompassing said tank for effecting a charge separation of the ion beam from said source; the improvement comprising a calcium boiler containing calcium and being mounted adjacent to said ion source, and heater means associated with said boiler for continuously vaporizing said calcium, a selected amount of said calcium being vaporized per hour, said boiler being provided with a vapor exit region for directing a calcium vapor into the path of said ion beam and encompassing the greatest portion of said ion beam, whereby said calcium vapor effects a reduction in the background pressure, provides for better resolution of said ion beam at said ion receiver, and effects an increase in the
  • said calcium boiler is provided with a charge bottle containing said calcium, a first set of heaters for heating said bottle, and a second set of heaters for heating said vapor exit region to a higher temperature than said bottle, said exit region being so shaped that the vapor exited therefrom has a cross section having about a 30 included angle.
  • said charge material to said ion source is selected from the group consisting of CS S CI SiS TiC1 W01 WCl HgS, and HgCl References Cited UNITED STATES PATENTS 1,638,551 8/1927 Ronci 313180 2,901,618 8/1959 Ludwig et al. 25041.9 2,921,199 1/1960 Davidson 25041.9

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  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Particle Accelerators (AREA)
US461568A 1965-06-04 1965-06-04 Calutron with means to direct calcium gettering vapor into the ion beam to reduce tank pressure Expired - Lifetime US3376414A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US461568A US3376414A (en) 1965-06-04 1965-06-04 Calutron with means to direct calcium gettering vapor into the ion beam to reduce tank pressure
GB19169/66A GB1114663A (en) 1965-06-04 1966-05-02 Improved vacuum pumping in calutrons
SE7701/66A SE318733B (cs) 1965-06-04 1966-06-06

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5279723A (en) * 1992-07-30 1994-01-18 As Represented By The United States Department Of Energy Filtered cathodic arc source
US20180021788A1 (en) * 2014-09-30 2018-01-25 Charles Burdick Device and Method for Remote Communications and Object Locomotion

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1638551A (en) * 1924-07-30 1927-08-09 Western Electric Co Electron-discharge device
US2901618A (en) * 1946-06-28 1959-08-25 Leon R Ludwig Calutron
US2921199A (en) * 1946-06-28 1960-01-12 Philip H Davidson Method of operating a calutron

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1638551A (en) * 1924-07-30 1927-08-09 Western Electric Co Electron-discharge device
US2901618A (en) * 1946-06-28 1959-08-25 Leon R Ludwig Calutron
US2921199A (en) * 1946-06-28 1960-01-12 Philip H Davidson Method of operating a calutron

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5279723A (en) * 1992-07-30 1994-01-18 As Represented By The United States Department Of Energy Filtered cathodic arc source
US20180021788A1 (en) * 2014-09-30 2018-01-25 Charles Burdick Device and Method for Remote Communications and Object Locomotion
US10857547B2 (en) * 2014-09-30 2020-12-08 Charles Burdick Device and method for remote communications and object locomotion

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GB1114663A (en) 1968-05-22
SE318733B (cs) 1969-12-15

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