BARC/PUB/2015/1131

 
 

Improved Faraday collector for magnetic sector mass spectrometers

 
     
 
Author(s)

Bhatia, R.,K.; Yadav, V. K.; Kumar, Y.; Gonde, B. R.; Ravisankar, E.; Saha, T. K.; Nataraju, V.; Gupta, S. K.
(TPD)

Source

International Journal of Mass Spectrometry, 2015. Vol. 393: pp. 58-62

ABSTRACT

Faraday collectors are used in isotopic ratio mass spectrometers for measurement of ion beam intensities.Ions striking the collector surface result in secondary electron emission that constitutes an error current.Typical collectors use electrical suppressors for minimizing current due to secondary electrons. However,due to mechanical errors in the placement of electrical suppressors, collection efficiency may vary fordifferent collectors. In present study, different techniques for reducing secondary electron contributionhave been investigated. These are: (a) use of magnetic field (instead of electric field) for secondary electronsuppression, (b) graphite coating to reduce secondary electron emission and (c) inclination of collectorto 45◦with respect to ion beam. Studies have resulted in a mechanically simpler design and improvedperformance that has been demonstrated by measurement of87Sr/86Sr isotopic ratio.

 
 
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