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Studies on some different configuration of multiwire-mesh proportional chambersOnly 14 pages are availabe for public view
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Abstract
The method of measuring the energy of a charged particle by means of the total amount of ionization it produces in coming to rest is well established in nuclear physics. At energies of a few million electron volts. it is sufficient to collect the ionization produced in a gas, on an electrode whose change of potential is aplified by a high gain linear amplifier. An output pulse whose size is a measure of the ionization can be obtained. The degree of amplification required is considerable and the fundamental noise of the amplifier sets a lower limit to the energy which can be studied. The noise is usually somewhat less than the pulse size from a particle of energy equal to 50 Kev. The 1imitation set by the noise can be overcome by the use of a proportional counter in which the noise initially produced are multipl1ed by collision in a region of high electric field before being collected. Proportional counters have bee n used for a long time in nuclear research but it was only comparatively recently that their full potentialities for measuring energies below the range of the pul.se ionization chamber were first appreciated. It was shown that the energy resolution was not seriously affected by the multiplication process(l). Moreover, there was no lower limit, set by the proportional counter, to the energy of radiation which could in principle be measured by ionization methods.