| 摘要 |
<p>PURPOSE:To enable a highly accurate measurement of neutrons in a wide range of temperature with a higher radioactivity by employing one kind or more of activated carbon and graphite and Al for a BF3 proportional counter as getter. CONSTITUTION:A BF3 gas 5 is put into a hollow cylinder 8 to be made a cathode and with terminal plates 3a and 3b closed, an anode 2 is spread on the center line thereof insulated from the cathod 8 while a connector 6 is mounted on the terminal plate 3b to draw electric signals. In a neutron detecting proportional measuring tube of such a type, one kind or more of activated charcoal and graphite are applied 9 on a part of the inner surface of the Al cylinder or granular matters thereof are sealed into the end of the tube. With such an arrangement, the activated charcoal and graphite act as getter up to about 150 deg.C but fail to do so over 200 deg.C and in stead Al starts to act as getter. Thus, the action of the getter can be retained at a high temperature of above 250 deg.C thereby enabling the detection and counting of neutrons in such a manner as to minimize deterioration in radiation in a wide range of temperature.</p> |
