Neutron Generators

[joseph.greco@kodak.com]

We will be upgrading our neutron generators (used for activation analysis)
in the near future.  There are model A-711 (High Output) made by MF
Physics, and use two 6.5 curie tritium sources as targets.  The tritium
resides on a thin film of zirconium, which in turn is deposited on a 10 mil
thick copper backing.  The targets are cooled by closed-loop water
circulation using de-ionized water.  The cooling water does not come in
direct contact with the tritiated side of the target, however tritium can
diffuse through the copper backing and be picked up by the cooling water.

Neutron flux delivered to sample is about 1E9 neutrons/cm2/sec.

Upgrades will include replacement of the water cooling unit and HV cables.
Radiological issues that I can forsee are activation products (primarily
short-lived copper isotopes) tritiated cooling water, and potential H-3
contamination of the cooling lines.  We're seeing about 0.1 microcuries of
H-3 per cc of water (9 liters total).  Gross beta analysis showed no
activation products (i.e., impurities) in the water.

Has anyone been involved in a similar situation?  What other rad issues
would you expect?


Joe Greco, RSO/LSO
Eastman Kodak Co
Rochester NY
joseph.greco@kodak.com







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