When I started my first attempts in neutron radiography (with film methods) around 1994 there was a meeting of a European working group on Neutron Radiography, where American and Canadian partners were also be invited. It took place at BAM (Bundesanstalt für Materialprüfung) in Berlin for three days with about 10 participants only, among them Jack Brenizer. Other prominent persons of that meeting I remember were J. Domanus (Riso, Denmark), persons from Petten (Netherlands), Saclay (France) and C. Fischer (HMI Berlin). They all had already much more experience than me – and I watched very carefully and with certain respect their presented details of studies. On a trip to USA, where I represented Switzerland in the program for the reduction in fuel enrichment for research reactors, about one year later, I met Jack a second time at his beam line of the Virginia University research reactor. I was very impressed by the radioscopy setup with video camera systems and light amplifiers in front. Unfortunately, this reactor was closed short time after – including the beam line for the real-time inspection of materials there. This was the reason why Jack returned to his initial education site – the Penn State University, where a professorship position was offered to him. At the same time, he got the access to a neutron imaging facility again because the reactor at Penn State continued running – until today. Maybe, Jacks activities at that reactor, in particular for neutron imaging, have been a strong argument to maintain the operation on good level into the present time – and in future. Later, we established a deeper contact for the preparation of conferences, exchange of knowledge and also performed private visits in both directions. In particular, he organized the “4th International Topical Meeting on Neutron Tomography” in 2001 with great success at Penn State and published the proceedings in good time. Jack was very active in the approach to standardize and to advertise neutron imaging in the U.S. and on te international level by his own studies and memberships in related committees. Before he retired in 2016, he was in Oak Ridge active as advisor for the upcoming neutron imaging facilities at ORNL. I was always impressed by his enthusiasm and optimism, supporting students and co-workers with pleasure.
Eberhard Lehmann