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Fission reactor flux monitors based on single‐crystal CVD diamond films
Author(s) -
Almaviva S.,
Marinelli M.,
Milani E.,
Prestopino G.,
Tucciarone A.,
Verona C.,
VeronaRinati G.,
Angelone M.,
Lattanzi D.,
Pillon M.,
Rosa R.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200776333
Subject(s) - diamond , neutron flux , materials science , neutron , neutron temperature , chemical vapor deposition , neutron detection , fission , crystal (programming language) , analytical chemistry (journal) , nuclear physics , optoelectronics , chemistry , physics , composite material , chromatography , computer science , programming language
Diamond based thermal neutron flux monitors have been fabricated using single crystal diamond films, grown by chemical vapour deposition. A 3 μm thick 6 LiF layer was thermally evaporated on the detector surface as a converting material for thermal neutron monitoring via the 6 Li(n, α) T nuclear reaction. The detectors were tested in a fission nuclear reactor. One of them was positioned 80 cm above the core mid‐plane, where the neutron flux is 2.2 × 10 9 neutrons/cm 2 s at 1 MW resulting in a device count rate of about 150000 cps. Good stability and reproducibility of the device output were proved over the whole reactor power range (up to 1 MW). During the irradiation, several pulse height spectra were recorded, in which both products of the 6 Li(n, α) T reaction, e.g. 2.73 MeV tritium and the 2.06 MeV α, were clearly identified, thus excluding a degradation of the detector response. A comparison with a reference fission chamber monitor pointed out a limitation of the adopted readout electronics at high count rates, due to multiple pile‐up processes. However, once this effect is properly accounted for, a good linearity of the diamond flux monitor response is observed as a function of the fission chamber one, as well as an excellent agreement between the temporal behaviour of the two detector response. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)