Improvement of ionization chamber for tritium measurements in in-pile tritium extraction experiments

摘要

Ionization chamber with gold plated wire-wall based on flange structure has been developed for tritium measurements in in-pile tritium extraction experiments. Performance of the improved ionization chamber on airtight and memory effect was greatly enhanced. Gas leakage rate of the chamber was lower than 1.0*10(-13) Pa.m(3)/s with the flange structure. Both tritiated water vapor and tritium in gaseous form have been used in experiments to examine the influence of memory effect caused by tritium absorption on chamber wall. Results indicate that with the design of gold plated wire wall, output signal of the ionization chamber can recover to background level within 1 min after 1 h exposure in tritiated water vapor at 3.0*10(8) Bq/m(3) created by bubbling. While recovery time is less than 20 s after being exposed to tritium in gaseous form at 3.9*10(10) Bq/m(3) for 7 days.