HOPG Pyrolytic Graphite neutron filters ?

[Alan Hewat]

I know the early references (Loopstra et al) to pryolytic graphite as a filter for 2.6A neutrons, but want to filter higher energies of ~3A eg. by reflecting just the specific 1.5A and 1A harmonics using highly oriented PG like a secondary monochromator-filter as was tried at ILL on IN14.

Does some-one have experience/references on this or other methods of filtering ~3A neutrons ? (I also know about Be-filters for 4+ A neutrons).

Does the following reference (which I don't have) say anything about this ?
Heller, H. and Saad, M., High-Oriented Pyrolytic Graphite as Neutron Filter. Part II. Second-Order Neutron Filter. Atomkernenergie (ATKE). Bd26 (1975), 274-275.

Finally, I know I can buy PG from http://www.advceramics.com/ but a few years ago there was also a much less expensive Russian source. Any recent experience here ?

Alan.

Dr Alan W. Hewat, Diffraction Group Leader.

Institut Laue-Langevin, BP 156X Grenoble FRANCE 38042

fax (33)4.76.20.76.48 tel (33)4.76.20.72.13 (or .26 Mme Guillermet)

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