Modification of older neutron probes to enable external data processing and control

Troxler Models 3223 and 3333 depth-moisture neutron probes were modified to allow external control and data recording. Complete procedures are present ed including a materials list, step-by-step instructions, and a circuit des ign. The procedure taken is low cost, effective, easy to complete, and grea tly increases the functionality of older neutron probes. This modification provides a good option for researchers wishing to upgrade existing instrume nts or in some cases, return an out-of-order meter to service.