American Nuclear Society

Home / Store / Journals / Electronic Articles / Nuclear Science and Engineering / Volume 50 / Number 1

A Pulsed Neutron Experiment with Beryllium by the Use of a Gamma-Ray Flash from an Electron Linear Accelerator

Otohiko Aizawa, Hiroyuki Kadotani, Keiji Kanda, Yoshiaki Fujita

Nuclear Science and Engineering

Volume 50 / Number 1 / January 1973 / Pages 38-45


Member Price:$27.00
Member Savings:$3.00

A new method of pulsed neutron experimentation is proposed and successfully applied to a beryllium metal system. The present technique utilizes the γ-ray flash from an electron linear accelerator. The employment of an “internal” neutron source, i.e., the (γ, n) reaction in beryllium, which is “softer” than the often used “external” 14-MeV neutrons from a generator, improves the state of the art of the die-away technique in beryllium. The reduction of background neutrons makes it possible to measure the decay curve until ∼ 1800 µsec after a burst even for a small beryllium assembly of 15 × 15 × 15 cm in dimension (B2 = 0.101 cm-2), while in earlier experiments the decay curves have been measured only until ∼600 µsec for such a small beryllium assembly. The present analysis of decay curves indicates that the assumption made by Kothari, who derived the limit of a discrete decay constant for crystalline moderators, is not valid at least for beryllium. On the other hand, Corngold’s limit is consistent with the experimental results.

Questions or comments about the site? Contact the ANS Webmaster.