US3857038A - Glow-tube for x-ray spectrometry with directly excited samples - Google Patents

Glow-tube for x-ray spectrometry with directly excited samples Download PDF

Info

Publication number
US3857038A
US3857038A US00318198A US31819872A US3857038A US 3857038 A US3857038 A US 3857038A US 00318198 A US00318198 A US 00318198A US 31819872 A US31819872 A US 31819872A US 3857038 A US3857038 A US 3857038A
Authority
US
United States
Prior art keywords
tube
glow
anode
cathode
casing
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
Application number
US00318198A
Other languages
English (en)
Inventor
J Sahores
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Societe Nationale des Petroles dAquitaine SA
Original Assignee
Societe Nationale des Petroles dAquitaine SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Societe Nationale des Petroles dAquitaine SA filed Critical Societe Nationale des Petroles dAquitaine SA
Application granted granted Critical
Publication of US3857038A publication Critical patent/US3857038A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/22—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material
    • G01N23/223—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by measuring secondary emission from the material by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
    • H01J3/02—Electron guns
    • H01J3/021—Electron guns using a field emission, photo emission, or secondary emission electron source
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/20—Selection of substances for gas fillings; Means for obtaining or maintaining the desired pressure within the tube, e.g. by gettering
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/07—Investigating materials by wave or particle radiation secondary emission
    • G01N2223/076—X-ray fluorescence

Definitions

  • Tubes used for X-ray spectrometry include ones which operate in a deep vacuum, of about 10 mm Hg,
  • Vacuum tubes with a heated filament require a deepvacuum installation, and emitting efficiency is low, because of the electrical energy expended in detaching the electrons from the filament.
  • These fluorescent tubes are either sealed, with a slit, or can be dismantled to allow the sample to be inserted into the vacuum chamber.
  • the presence of the slit prevents the passage of retrodiffused electrons and soft X-photons with a long wavelength, needed to analyse elements with low atomic weight, while the need to place the sample in a vacuum enclosure means that only materials which will not produce degassing can be analysed.
  • the sample, acting as anode is exposed to intense bombardment by electrons, and can begin to melt, altering its surface composition.
  • glow-tubes with a cold cathode emitting a mixture of electrons and hard X-rays, and with no slit, which operate in a partial vacuum of 10 to 10' mm Hg, comparable to the vacuum prevailing in v a spectrometry chamber.
  • Exciting of the sample comes from a mixed source, since it receives a simultaneous beam of X-rays and electrons retrodiffused by the anode. During this retrodiffusion, ions are removed from the anode metal and deposited on the sample.
  • This metal-coating effect is a disadvantage, creating a film which absorbs the X-rays emitted by the sample, and distorting the results of spectrometric analysis.
  • at short wavelengths and large amounts of energy transmitted to the sample and needed to excite its characteristic lines could damage substances affected by heat.
  • the present invention concerns a glow-tube without a slit, which overcomes these drawbacks, emitting electrons directly, and with high efficiency. More specifically, it concerns a tube containing a cathode consisting of a metal disc, and a grid-shaped anode, both electrodes being located in the axis of the tube, with an opening on the same axis behind the anode, through which the electron beam is propagated by inertia, in the direction of the target.
  • the tube defined in this invention allows a sample to be excited directly, by direct emission of electrons, without any photons.
  • the energy spectrum of direct, non-retrodiffused electrons is narrower than for retrodiffused electrons, so that energy is saved, since the flux needed to excite any line in the sample is much smaller. This ensures much higher emission efficiency, and prevents damage to the sample from heat.
  • the anode is in the form of a grid, so that the sam plc is not exposed to any direct trajectory starting at the wires of the anode grid receiving the electron impacts.
  • the tube described in the invention ensures high emission efficiency, up to in contrast to conventional fluorescent tubes (the ratio of energy absorbed to energy emitted is approximately 10 Compared with existing direct-emission tubes, it offers many advantages, operating without a deep vacuum, in a partial vacuum of approximately l0" to 10 mm Hg; and since the sample does not form part of the electronic optical system, it need not be a conductor.
  • the use of a grid-shaped anode offers many advantages. Its role is to attract the electrons in the direction of the tube-casing axis, and allow the electron beam to pass through the grid without loss of energy.
  • the electrical field set up between the cathode and anode results only from the potential between them and, in the absence of any conducting body in the space through which this beam passes, radiation is perfectly rectilinear and trajectories are parallel. This means that the surface even of a large'sample is subjected to uniform radiation, preventing localized temperature rises that could damage the surface.
  • the electrons are propagated in a parallel beam, so that their velocities are not subject to localized variations. Since the energy spectrum emitted is narrow, the exciting efficiency for a characteristic line remains high.
  • Choice of the transmission coefficient of the grid allows the intensity of the radiation flux to be controlled for a given amount of electrical energy, notably if there is a possibility of heat damaging the sample.
  • Choice of the surface-area of the grid allows it to be adapted to the size. of the samples being subjected to radiation, without altering the electrical. and energy characteristics of the beam emitted;
  • the tube described in the invention thus allows great versatility in the use of equipment, which is also dependent on a fixed energy-supply source.
  • FIG. 4 shows a tube according to the present invention attached to a base for mounting it in a spectrometer.
  • FIG. 1 shows, in diagrammatical form, the positioning of the electrodes inside the insulating casing 1.
  • the cathode 2 is a disc or pellet made from metal with a high electron-emitting capacity and good resistance to ionic erosion, such as aluminium.
  • the anode 3 is a metal-grid made from rhodium, rhenium or platinum, and connected to earth.
  • the electron beam 4 emitted by the cathode travels towards the anode, and is propagated by inertia in the direction of the sample 5 placed in its path.
  • the X-ray beam emitted by the sample following exciting of the characteristic lines of the elements of which it is formed, is then treated by standard spectrometric methods, using a collimator, crystal and meter, arranged as a goniometer.
  • FIG. 2 shows the constructional details of the tube, according to a recommended embodiment of the invention.
  • the casing is in two parts (1a and lb), which slide inside each other.
  • a cathode 2 fixed to a threaded rod 6, the length of which can be adjusted and which is held by nuts 7 in the end of the casing.
  • the electrical connections 8 are placed inside a flexible insulating covering 9.
  • the cathode rod may be attached to a radiator with cooling fins.
  • the outer casing lb has an anode 3 near the end, in the form of a grid connected with earth, with a ring 10, which holds it in a groove on the inner surface of the casing.
  • the otuer casing has a capillary inlet pipe 1 1 through which an adjustable flow of gas can be fed in, and the inner casing has an outlet 12, so that pressure inside the tube can be kept constant or vary.
  • An O-ring 13 between the two casings ensures proper sealing.
  • the distance between the electrodes can be adjusted by sliding cent tube with the slit 16 in a transverse direction in relation to the axis of the tube 1 and its cylindrical base 17.
  • the surface 18 provides a seal during fitting to a spectrometer.
  • the tube described in the invention can be used not only for X-ray spectrometric analysis, but also for structural analysis by diffraction (lattice of a crystalline phase or the structure of a liquid) or by scattering (measurement of the dimensions of particles, mixtures, etc.).
  • a glow-tube for use in X-ray spectrometry with directly excited samples, said glow-tube comprising at least one elongated insulating casing having an opening in one end thereof and containing a disc-shaped cathode and a grid-shaped anode, said cathode and anode being aligned longitudinally of said casing with said anode between said cathode and opening, said tube being adapted to propagate an electron beam which passes through said opening when said cathode is connected to a high voltage source and said anode is connected to ground.

Landscapes

  • General Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)
  • Luminescent Compositions (AREA)
  • Lasers (AREA)
  • X-Ray Techniques (AREA)
US00318198A 1971-12-29 1972-12-26 Glow-tube for x-ray spectrometry with directly excited samples Expired - Lifetime US3857038A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7147290A FR2166539A5 (fr) 1971-12-29 1971-12-29

Publications (1)

Publication Number Publication Date
US3857038A true US3857038A (en) 1974-12-24

Family

ID=9088303

Family Applications (1)

Application Number Title Priority Date Filing Date
US00318198A Expired - Lifetime US3857038A (en) 1971-12-29 1972-12-26 Glow-tube for x-ray spectrometry with directly excited samples

Country Status (23)

Country Link
US (1) US3857038A (fr)
JP (1) JPS4881585A (fr)
AR (1) AR193002A1 (fr)
AT (1) AT346434B (fr)
AU (1) AU467584B2 (fr)
BE (1) BE793443A (fr)
BR (1) BR7209161D0 (fr)
CA (1) CA994480A (fr)
CH (1) CH569362A5 (fr)
CS (1) CS174866B2 (fr)
DD (1) DD102860A5 (fr)
DE (1) DE2264191A1 (fr)
ES (1) ES410109A1 (fr)
FR (1) FR2166539A5 (fr)
GB (1) GB1409309A (fr)
HK (1) HK14077A (fr)
IL (1) IL41186A (fr)
IT (1) IT972979B (fr)
LU (1) LU66756A1 (fr)
NL (1) NL7217759A (fr)
NO (1) NO139394C (fr)
OA (1) OA04232A (fr)
ZA (1) ZA729131B (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CS268377B1 (en) * 1988-04-08 1990-03-14 Emil Ing Vratnicek Electron gun for electron microscope

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2521656A (en) * 1945-12-13 1950-09-05 Emilio G Segre Ionization chamber
US3118064A (en) * 1961-08-30 1964-01-14 Frank H Attix New type of free air ionization chamber
US3373283A (en) * 1963-06-11 1968-03-12 Commissariat Energie Atomique Device for triggering a nuclear particle detector of the gas type
US3601612A (en) * 1969-08-22 1971-08-24 Atomic Energy Commission Wire spark chamber with magnetostrictive readout
US3681600A (en) * 1969-10-24 1972-08-01 Perkin Elmer Corp Retarding field electron spectrometer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2521656A (en) * 1945-12-13 1950-09-05 Emilio G Segre Ionization chamber
US3118064A (en) * 1961-08-30 1964-01-14 Frank H Attix New type of free air ionization chamber
US3373283A (en) * 1963-06-11 1968-03-12 Commissariat Energie Atomique Device for triggering a nuclear particle detector of the gas type
US3601612A (en) * 1969-08-22 1971-08-24 Atomic Energy Commission Wire spark chamber with magnetostrictive readout
US3681600A (en) * 1969-10-24 1972-08-01 Perkin Elmer Corp Retarding field electron spectrometer

Also Published As

Publication number Publication date
ZA729131B (en) 1973-11-28
IL41186A0 (en) 1973-02-28
ATA1116072A (de) 1978-03-15
NL7217759A (fr) 1973-07-03
IL41186A (en) 1976-04-30
AU467584B2 (en) 1974-07-04
GB1409309A (en) 1975-10-08
AR193002A1 (es) 1973-03-21
JPS4881585A (fr) 1973-10-31
NO139394C (no) 1979-02-28
BR7209161D0 (pt) 1973-09-25
HK14077A (en) 1977-04-01
ES410109A1 (es) 1975-12-16
FR2166539A5 (fr) 1973-08-17
BE793443A (fr) 1973-04-16
OA04232A (fr) 1979-12-31
CA994480A (fr) 1976-08-03
CH569362A5 (fr) 1975-11-14
NO139394B (no) 1978-11-20
DE2264191A1 (de) 1973-07-05
CS174866B2 (fr) 1977-04-29
DD102860A5 (fr) 1973-12-20
AU5055772A (en) 1974-07-04
AT346434B (de) 1978-11-10
LU66756A1 (fr) 1973-02-27
IT972979B (it) 1974-05-31

Similar Documents

Publication Publication Date Title
US4075526A (en) Hot-cathode x-ray tube having an end-mounted anode
Oliphant The liberation of electrons from metal surfaces by positive ions. Part I.—Experimental
Dos Santos et al. Development of portable gas proportional scintillation counters for x‐ray spectrometry
Mattson et al. The application of a soft X-ray spectrometer to study the oxygen and fluorine emission lines from oxides and fluorides
US4701941A (en) Radiation source
Tallman et al. Determination of the minimum x‐ray flux for effective preionization of an XeCl laser
US2720593A (en) Scintillation-type ion detector
US3857038A (en) Glow-tube for x-ray spectrometry with directly excited samples
Samson et al. Duoplasmatron as a vacuum ultraviolet light source
Ahlberg et al. Experimental comparison of photon‐and particle‐induced X‐ray emission analysis of air particulate matter
US3011060A (en) X-ray spectrograph
DOWbING et al. COUNTERS FOR X;. RAY ANALYSIS
JPH0756781B2 (ja) 中空陰極放電管
Alexander et al. Characterization of a saddle-field discharge gun for FABMS using different discharge vapours
US6617771B2 (en) Electron ionization ion source
US2347424A (en) X-ray tube
Mori et al. Photoelectric emission of metals by x-rays in the keV region
Palmer Recent advances in gas scintillation proportional counters
Luggar et al. Electronically gated multiemitter x-ray source for high-speed tomography
Duan et al. Characterization of an improved thermal ionization cavity source for mass spectrometry
Strachan et al. Bombardment of Various Elements by Hg+ and A+ Ions
RU2291469C1 (ru) Газовый пропорционально-сцинтилляционный детектор
Dershem A Shielded Filament X‐Ray Tube for Pure X‐Ray Spectra
Bosch et al. A simultaneous angle-resolved photoelectron spectrometer
US3435211A (en) Gaseous glow discharge tube with cathode means surrounding anode means