IL23202A - Method of activation of thermionic sources and thermionic source obtained by application of said method or a like method - Google Patents

Method of activation of thermionic sources and thermionic source obtained by application of said method or a like method

Info

Publication number
IL23202A
IL23202A IL2320265A IL2320265A IL23202A IL 23202 A IL23202 A IL 23202A IL 2320265 A IL2320265 A IL 2320265A IL 2320265 A IL2320265 A IL 2320265A IL 23202 A IL23202 A IL 23202A
Authority
IL
Israel
Prior art keywords
refractory
substance
thermionic
filament
layer
Prior art date
Application number
IL2320265A
Other languages
Hebrew (he)
Original Assignee
Commissariat Energie Atomique
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 Commissariat Energie Atomique filed Critical Commissariat Energie Atomique
Publication of IL23202A publication Critical patent/IL23202A/en

Links

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J27/00Ion beam tubes
    • H01J27/02Ion sources; Ion guns
    • H01J27/26Ion sources; Ion guns using surface ionisation, e.g. field effect ion sources, thermionic ion sources
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00Particle spectrometers or separator tubes
    • H01J49/02Details
    • H01J49/10Ion sources; Ion guns
    • H01J49/16Ion sources; Ion guns using surface ionisation, e.g. field-, thermionic- or photo-emission

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Analytical Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Electron Tubes For Measurement (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Sampling And Sample Adjustment (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Description

Method of activation o thermionic sources and source obtained by application of said method or a method COMMISSARIAT A 22262 2 this invention relates to a of motivation of a thermionic source which la for ase in mass emission of a thermionic source is governed wherein a de the ionization yield is a the function of the filament 0 the ionization potential of the element studied the constant absolute The ratio defines the ionization yield and in o order to increase this it is necessary to activate a thermionic In the case of a given increase can only be obtained by producing a variation of the absolute temperature or the value of the difference increase in temperature is of course limited by the value of the melting points the constituents of the source and only a modification of of real To this the invention has for its ob ect a method of activation of a thermionic source which can be employed in mass spectrometry and which makes it possible to increase the function of the filament invention consists in a method which comprises depositing on a metallic filament a layer of refractory refractory activating substance until said constituent has been eliminated and the refractory layer has thereby been rendered charging the thus obtained with a re consisting of refractory activating substance and of the product to be by mass spectrometry and calcining The thermionic source prepared in this manner can be employed the purpose o performing the analysis by means of mass it comprises a heating filament coated with a layer of refractory activating substance which is in turn coated with a layer consisting ofa mixture of the activating substance and of the substance to be The apart from being must have a state of the surface of the activator is of primary importance since the Object to be achieved is the modification of the work function I of the filament fhe activator must be prepared in such manner as to exhibit a porous surface after For this the activators will be chosen among those substances which are capable of an occluded substance as a result of Substances which these conditions for the and they may be singly or in combinations magnesium silicate in the form of a thorium in the form of a hdrated gel zirconium oxide in the form of a hydrated This list not and compounds from which a substance other than water can be by heating be contemplated for use ae embodiment of the according to the applied to the preparation of an activated thermionic source described belo by of example heating filament consists of a metal having a high advantageously rhenium or The form of a hydrated is deposited on the filament by mesne of a platinum coated filament then subjected to a first calcining treatment by an electric current passing through the by the Joule The activator layer is thereby dried and the water of the hydrated gel evaporates leaves behind a porous Sh heating must bo performed with care and in such a manner that the activator layer firmly adheres to the ilament after the The filament thus covered the activator is then covered with a mixture of the activating substance with the product to be he quantities employed must be small since it would prove undesirable to overload the calcination of the loaded filament then effected in the same manner as After the completion of these various the activated filament comprises a thin layer of activator deposited on the the of the layer may vary between and 1 am but amounts preferably to about The activating soon the vacuum the source has been brought to the desired the appearance of the spectrum is studied and there are first observed the which result from occluded gases within the activator and which can rapidly by a slight increase in e corresponding to the of the product to be analysed then appear and the emission can be very easily An analysis by spectrometry of a mixture of lead for can be performed without previous extraction of the lead directly on a sample of oro in solid form such as or any other ore which contains traces of In the utilization of a thermionic source prepared in accordance with the invention makes it possible to reduce to a considerable extent the minimum quantities of product to be whic are required an For a sample of 3 of zircon estimated at two thousand million years and containing per of and in which the ratio of lead to uranium was in the vicinity of has been this quantity of con corresponds to t x of As the of to in this example of the orde of the quantity of employed is x 10 account being taken of the presence of the was possible to measure amount of lead 204 present since it is known that the proportion of 204 contained in lead is approxim it can be assumed that the proportion of lead 204 is The peak which is observed and which corresponds to lead 204 therefore a quantity f 10 g lead It oan therefore be seen that a thermionic source in accordance with the makes it possible to employ only very small quantities of products to be the figures iiven above must not be considere as a lower limit of the measurable quantities of lead since it must be recalled in the case under considera lead is conceale within the A thermionic source in accordance the invention has the great n particular for analyses by mass hat the product to fee analyzed can be utilized in solid form and thus requires only a minimum number of the practical embodiment of the invention described above of been solel by way o example and thermionic sources prepared accordance the invention can be employed or performing the Isotopie analysis o other elements such for uranium or insufficientOCRQuality

Claims (1)

1. CLAIMS A method of activation a thermionic source which is intended for in comprising depositing on a metallic a layer of refractory substance containing a constituent can he b calcining the filament which is coated with the refractory aotlvating substance until said constituent has been eliminated and the refractory layer has thereby been rendered charging aggregate thus obtained with a mixture slating of the refractory aotlvating substance and of the product to by mass spectrometry and in calcining the A according to Claim wherein the refractory aotlvating substance deposited on the metallic consists one or more of the following magnesium silicate in the form of a hydrated gel to thorium in the of a hydrated gel prior to silica gel oxide in the form of hydrated gel prior to A thermionic comprising a heating filament of a conductive substance having a high melting a porosity layer of a refractory activating substance covering the filament and havin a poor thermal conductivity and poor electrical and an outer layer containing a mixture f the product to be and of said h rmionic su e accordin to Claim wherein the Claim For the Applicants insufficientOCRQuality
IL2320265A 1964-03-27 1965-03-23 Method of activation of thermionic sources and thermionic source obtained by application of said method or a like method IL23202A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR968986A FR1398136A (en) 1964-03-27 1964-03-27 Process for activating thermionic sources and thermionic source in accordance with those obtained by applying said process or a similar process

Publications (1)

Publication Number Publication Date
IL23202A true IL23202A (en) 1968-09-26

Family

ID=8826562

Family Applications (1)

Application Number Title Priority Date Filing Date
IL2320265A IL23202A (en) 1964-03-27 1965-03-23 Method of activation of thermionic sources and thermionic source obtained by application of said method or a like method

Country Status (10)

Country Link
BE (1) BE661231A (en)
CH (1) CH432055A (en)
DE (1) DE1297901B (en)
ES (1) ES311083A1 (en)
FR (1) FR1398136A (en)
GB (1) GB1099782A (en)
IL (1) IL23202A (en)
LU (1) LU48248A1 (en)
NL (1) NL6503984A (en)
SE (1) SE302647B (en)

Also Published As

Publication number Publication date
DE1297901B (en) 1969-06-19
BE661231A (en) 1965-07-16
ES311083A1 (en) 1966-04-16
CH432055A (en) 1967-03-15
LU48248A1 (en) 1965-05-24
SE302647B (en) 1968-07-29
NL6503984A (en) 1965-09-28
FR1398136A (en) 1965-05-07
GB1099782A (en) 1968-01-17

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