1985 年 20 巻 4 号 p. 371-378
Two Important problems about commonly-used neutron rem-counter have been discussed in evaluating the neutron dose equivalent in pulsed and mixed radiation fields around an electron linear accelerator. One is the overestimate of dose equivalent due to false pulses generated by intense burst X-rays. In order to eliminate the false pulses, three techniques based on (1) anti-coincidence counting, (2) pulse height discrimination, and (3) correction factor have been employed. It was pointed out that the first technique was most effective and the third was most convenient for practical applications. The other problem is the underestimate of dose equivalent due to counting loss in a high-fluence-rate field. It was confirmed that the time variation of counting rate was an important factor for dead-time correction in pulsed radiation fields. A comparison between dose equivalent values evaluated with rem-counter and those with Indium activation detector has also been carried out. A validity of proposed correction methods was confirmed from the experimental results of the proportionality of the corrected dose equivalent values to the relative activity of Indium detectors.