caa a22 4500 397502621 CHVBK 20180308164536.0 cr unu---uuuuu 161202e19950801xx s 000 0 eng 10.1093/oxfordjournals.rpd.a082793 doi 0144-8420 pii (NATIONALLICENCE)oxford-10.1093/oxfordjournals.rpd.a082793 Takata N. Effects of the Electric Field on Ionisation in Two Different Types of Ionisation Chambers [Elektronische Daten] [N. Takata] A parallel plate cavity ionisation chamber was irradiated with 60Co ? rays from the polarising electrode. Beyond the recombination region, the output current of the chamber increases (decreases) linearly with applied positive (negative) voltage. This effect is attributed to the change in the stopping power of air due to acceleration or deceleration of secondary electrons in the applied electric field. In a free-air ionisation chamber, secondary electrons emitted in the direction of the electric field lose energy and those emitted in the opposite direction gain energy and, hence, cause a reduction or enhancement in ionisation, respectively. Computer calculations have shown that the enhancement and reduction are in a range from 0.15 to 0.3% when exposure is measured for X rays generated at a tube voltage of 60-300 kV and at an electric field strength of 20 kV.m-1. The net increase in the output current charge at this field strength is smaller than the calculation uncertainties. Radiation Protection Dosimetry Radiation Protection Dosimetry Oxford University Press 61/1-3(1995-08-01), 253-256 0144-8420 61:1-3<253 1995 61 rpd https://doi.org/10.1093/oxfordjournals.rpd.a082793 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.rpd.a082793 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Takata N. NATIONALLICENCE 773 0- Radiation Protection Dosimetry Oxford University Press 61/1-3(1995-08-01), 253-256 0144-8420 61:1-3<253 1995 61 rpd Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford