US2990491A - Far ultraviolet light source - Google Patents
Far ultraviolet light source Download PDFInfo
- Publication number
- US2990491A US2990491A US751747A US75174758A US2990491A US 2990491 A US2990491 A US 2990491A US 751747 A US751747 A US 751747A US 75174758 A US75174758 A US 75174758A US 2990491 A US2990491 A US 2990491A
- Authority
- US
- United States
- Prior art keywords
- far ultraviolet
- enclosure
- ultraviolet light
- tritium
- light source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J65/00—Lamps without any electrode inside the vessel; Lamps with at least one main electrode outside the vessel
- H01J65/06—Lamps in which a gas filling is excited to luminesce by radioactive material structurally associated with the lamp, e.g. inside the vessel
Definitions
- This invention relates to ultraviolet light sources, and in particular to devices for enerating far ultraviolet rg diation with a wavelength of a on 'ngstrom It has been determined that air is substantially transparent to radiation with a wavelength of about 1216 A., but that water is highly absorbent of such radiation. These properties form the basis for a system for determining the moisture or water-vapor content in the air.
- the system comprises a source of the 1216 A.
- FIG. 1 is a cross-sectional view of one form of the far ultraviolet light source of the invention
- FIG. 2 is a cross-sectional view of a modification.
- FIG. 1 a sealed enclosure 1 which may be made of glass, metal, or any other substantially gas-tight material which is opaque to radiation-of a wavelength of 1216 A.
- One wall of the enclosure contains a window 2 which is substantially transparent to far ultraviolet light or radiation with a wavelength of about 1216 A.
- a suitable window material for this radiation is lithium fluoride.
- the opposite wall of the enclosure has been employed for introducing a desired gas into the enclosure and for thereafter sealing-off the enclosure, which is shown by reference numeral 3.
- a quantity of radioactive tn'tium gas 4 at a pressure of, for example, one atmosphere, which is not at all critical as the pressure or the amount of the tritium present merely determines the intensity of the light output.
- Radioactive tritium a heavy isotope of hydrogen
- Radioactive tritium has a half-life of 12.26 years.
- beta particles are emitted, with amaximum energy of about 18 kev. and an average energy of about 5 kev., and no gamma radiations.
- amaximum energy about 18 kev.
- average energy about 5 kev.
- about -2,990,491 Patented June 27, 1961 ice 3X10 beta particles are produced per second for each curie of the radioactive material, and each cubic centimeter of this gas at atmospheric pressure contains about having a far ultraviolet ligh't tr t n spa g e of transmr mg ra 1a lon wilh" a wavele 2.7 curies.
- the beta particles emitted by the radioactive tritium dissociate hydrogen and tritium molecules present in the enclosure and the hydrogen atoms thereby produced in addition to tritium atoms in the enclosure are excited by the beta particles to emit a series of spectral lines which include the desired radiation of about 1216 A.
- the hydrogen present in the gas either arises from dissociated tritium, or a quantity of non-radioactive hydrogen may be mixed in with the radioactive tritium. The proportions of this mixture are not critical and will depend upon the pressures desired of the gas within the enclosure.
- the emitted 1216 A. radiation traverses the transparent window portion 2 and is thus made available on the outside of the enclosure, which has been indicated by dotted lines designated by reference numeral 5.
- the far ultraviolet light source thus described has several important advantages. Firstly, the device is selfcontained and is characterized by an extremely simple structure which nevertheless has a very long life and is very stable. Further, a most important feature is that no spurious radiation outside of the light range, visible or near-visible, emanates from the source, that is, no beta particles emanate from the source nor is there any gamma emission produced during the decaying process. No betas are emitted because those produced by the decay of the radioactive tritium which are not absorbed by the gas itself are, because they are of such low-level energy, readily absorbed in the walls and the window constituting the enclosure for the gas.
- FIG. 2 shows a modification of the device of the invention in which a heated member, shown as a filament 6 capable of being heated by the passage of current therethrough, is mounted within the gas-filled enclosure.
- a heated member shown as a filament 6 capable of being heated by the passage of current therethrough
- the presence of a heated member causes dissociation of molecular hydrogen or molecular tritium present in the euclosure and thus makes available more atomic hydrogen or tritium for excitation by the emitted beta particles from the decaying tritium.
- the filament may be made of tungsten or of like conventional filament material.
- the far ultraviolet opaque wall portions 1 may be provided with a metallized surface 7 serving as a reflector to increase the intensity of the light output in the desired direction.
- a suitable material for this purpose is platinum.
- a far ultraviolet light source for generating radiation with a wavelength of about 1216 A. comprising a sealed enclosure containing a far ultraviolet light-opaque portion and a far ultraviolet light-transparent window portion capable of transmitting 1216 A. radiation, and radio active tritium gas within the enclosure.
- a source as set forth in claim 3 including means for 7.
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
- Discharge Lamp (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL241561D NL241561A (fr) | 1958-07-29 | ||
NL125811D NL125811C (fr) | 1958-07-29 | ||
US751747A US2990491A (en) | 1958-07-29 | 1958-07-29 | Far ultraviolet light source |
GB25506/59A GB907986A (en) | 1958-07-29 | 1959-07-24 | Improvements in or relating to ultraviolet radiation sources |
DEN17024A DE1085965B (de) | 1958-07-29 | 1959-07-25 | Quelle extrem-ultravioletten Lichtes |
FR801369A FR1234391A (fr) | 1958-07-29 | 1959-07-28 | Source de lumière dans l'ultraviolet lointain |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US751747A US2990491A (en) | 1958-07-29 | 1958-07-29 | Far ultraviolet light source |
Publications (1)
Publication Number | Publication Date |
---|---|
US2990491A true US2990491A (en) | 1961-06-27 |
Family
ID=25023312
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US751747A Expired - Lifetime US2990491A (en) | 1958-07-29 | 1958-07-29 | Far ultraviolet light source |
Country Status (5)
Country | Link |
---|---|
US (1) | US2990491A (fr) |
DE (1) | DE1085965B (fr) |
FR (1) | FR1234391A (fr) |
GB (1) | GB907986A (fr) |
NL (2) | NL241561A (fr) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3535576A (en) * | 1968-11-21 | 1970-10-20 | Honeywell Inc | Photoionization device with electrodes attached to exterior of envelope |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2430089A1 (fr) * | 1978-06-28 | 1980-01-25 | Anvar | Perfectionnements aux lampes spectrales |
US4818915A (en) * | 1987-10-22 | 1989-04-04 | Gte Products Corporation | Arc discharge lamp with ultraviolet radiation starting source |
US4812714A (en) * | 1987-10-22 | 1989-03-14 | Gte Products Corporation | Arc discharge lamp with electrodeless ultraviolet radiation starting source |
GB2424755A (en) * | 2005-03-31 | 2006-10-04 | Heraeus Nobelight Analytics Lt | A low-pressure discharge lamp for a photoionisation detector |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2699515A (en) * | 1953-08-21 | 1955-01-11 | Gordon E Williams | Lamp construction |
US2804573A (en) * | 1954-01-21 | 1957-08-27 | William J Arrol | Gas discharge devices |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB646414A (en) * | 1946-05-31 | 1950-11-22 | Egyesuelt Izzolampa | Improvements in and relating to fluorescent luminous bodies |
-
0
- NL NL125811D patent/NL125811C/xx active
- NL NL241561D patent/NL241561A/xx unknown
-
1958
- 1958-07-29 US US751747A patent/US2990491A/en not_active Expired - Lifetime
-
1959
- 1959-07-24 GB GB25506/59A patent/GB907986A/en not_active Expired
- 1959-07-25 DE DEN17024A patent/DE1085965B/de active Pending
- 1959-07-28 FR FR801369A patent/FR1234391A/fr not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2699515A (en) * | 1953-08-21 | 1955-01-11 | Gordon E Williams | Lamp construction |
US2804573A (en) * | 1954-01-21 | 1957-08-27 | William J Arrol | Gas discharge devices |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3535576A (en) * | 1968-11-21 | 1970-10-20 | Honeywell Inc | Photoionization device with electrodes attached to exterior of envelope |
Also Published As
Publication number | Publication date |
---|---|
NL241561A (fr) | |
GB907986A (en) | 1962-10-10 |
FR1234391A (fr) | 1960-10-17 |
DE1085965B (de) | 1960-07-28 |
NL125811C (fr) | 1968-12-17 |
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