BARC/PUB/2003/0375

 
 

Indigenous development of gamma compensated boron lined neutron chambers

 
     
 
Author(s)

Alex, M.; Prasad, D. N.; Prasad, K. R.; Kataria, S. K.; Athavale, S. N.; Pappachan, A. L.; Subramanian, C.; Grover, A. K.; Suri, A. K.
(MPD)

Source

Journal of Scientific and Industrial Research, 2003. Vol. 62 (11): pp. 1057-1062

ABSTRACT

γ-compensated boron-lined ionisation chambers are indigenously developed for neutron monitoring applications in reactors using inexpensive and easily available polyether ether ketone (PEEK) insulating material as an alternative to alumina. The chamber has overall diam of 8.5cm and 31.5 cm length 0.7g of indigenously developed 40.5 per cent enriched boron is dip coated on the electrodes. The chamber has neutron sensitivity of 5.5fA/nv and an average γ-compensation factor of 4 per cent. The performance of the neutron detector is compared with a similar detector with alumina discs. The use of suitably shaped PEEK inserts at the ends of the electrodes eliminates extra-cameral volume. This results in more uniform electric field and well -defined sensitive volume between the electrodes. As a result the chamber with PEEK insert requires 50V to saturate as compared to 100V in the case of the chamber with alumina discs when exposed to thermal neutron flux of 108nv. The variation in γ-compensation factor reduces from ± 9 to ± 4.5 per cent between 300 to 3150 R/h. The indigenous development of the detector helps avoid long-term dependence on imports and also saves substantial amount of foreign exchange.

 
 
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