Chakraborty, P

Dey, S D

English

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Indian J. Phys. 51B, 473-474 (1977)Apparatus for the study of secondary ions from solid surfaces under ion bombardmentP . C h a k r a b o r i y  a n d  S. D. Di .yMass Si>e0tf*ascopy and Isotope Separator Ijahoratory,Saha Institute o f Nuclear Physics,In order lo study the inleraction of ions with solid surEaces, we have developed a quad'rupole mass spectrometer to analyse the secondary sputtered ions arising due to ion-sorid inleraction. Of particular inlteresit is tJie emission of singly charged, molecular cluster ions, characteristic of the solid sample.The setting up of a quadrupolc mass spectrometer has already been reported by Dey et al (1975). The nutsis spectrometer could handle mass up to 100, the radio-frequency used having been 4 mc/scc. In order to to handle heavier mass, certain changes were incorporated in the electronic circuitry. With the limited r f . power available for the generatkm of the r.l, field in the space between the rods- of the quadrupolc analyser, the frequency of the r.f. system had to be changed from 4 mc/scc to 3 mc/scc. Havihg (ione^this, we have been able to extend the mass range of the inhilrument up to about 200.An ion-souroo, developed by IJhler et al (1968), has been set up and tested to generate energetic ions (up to ~  10 KeV) lor bombardniCTl purposes. The testing was done using Ar and Zn. The ion-source is cajrdblc of handling both solids and gases. The cnergotic ions were made moident on a polycrystalline surface inclined at an angle of 45° wJlh the direction of the primary ion beam. Tho primary current dcn.sity at the target surface was (2-3) ma/cm5. xhe secondary sputtered ions, ejected from the t a r ^  surface, were extracted, accelerated and collimated by a leas system at to the primary beam direction. The .sccondnry i.>ns were then passed through the quadrupolc field, the last ground sJit in front of the quadrupolc had a circular aperture of diameter 14 mil. A block diagram of the expenm m a set-up is shown in Fig. 1. The chamber enclosing the ion-source, target box, quadrupolc mass filler and the electron multiplier etc. was eva^ate up o a pressure ~  lO-'  ^ mm of Hg by oil diffu.sion pumps provided' with liquidair traps.So far we have bombarded polycrystalline copper s u rfa ^  using e n c r ^ K  Zn+ ions. The copper sample was electrolylically pure. Sputtenng yieJa474 P. Chakraborty and S. Deyh i^ r  if lighter targets ate bombarded by heavier projectile Jons. It is planned to bombard Cu, A1 and Ni targets by Zn+ and Cd+ ions.««ttOMomF)g. I. Block diagram of the experimental set-upi.A pteiUminary analysis of the secondary ions produced due to Zn+—Cu interaction showed presence of Cu++, Cu+, Cu+a, Cu+s and C11O+ ions. The ions, after being analysed by the quadrupole mass spectrometer, were detected by a 10-stage Ag*Mg electrem multiplier, (Dumont SP. 182) operated at a gain of 10^ , followed by a vibratkigreed electrometer and a pen recorder.R eferencesDey S. D., Kamohapatra S. B. and Banerjee B. M. I97.*t Ind. J. Phys^  49, 797, Uhkr J. and Alvager T. 196i8 Arkiv. Fysik 14, 473.

Apparatus for the Study of Secondary Ions from Solid Surfaces Under Ion Bombardment

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Apparatus for the Study of Secondary Ions from Solid Surfaces Under Ion Bombardment

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