Further Measurements on the Disintegration Curve of Mesotrons

'HE authors of the present paper have recently described a method for the experimental determination of the disintegration curve of Tnesotrons and have given a preliminary account of the results obtained. ' The method has been since improved and a new and more extensive set of data has been taken. A summary of the riew results is presented here. The experimental arrangement, which is similar in principle to that used in the previous experiment, is schematically represented in Fig. 1. The three counters L are in parallel, and so are the four counters 8 and the five counters JI. Counters A, ~, A2, and 8 feed into the "time circuit" T; this circuit gives a pulse whose amplitude is a function of the time delay between a coincidence A &A2 and the subsequent pulse of 8. Counters L, A1, A~, 8, and M feed into an anticoincidence circuit C, which records the anticoincidences LA1A28 —2VI, i.e. , the coincidences between LA1A2 and 8 which are not accompanied by a pulse in lK The recording circuit R operates a pen writing instrument in such a way that the pulse from the time circuit is recorded only when it is accompanied by a pulse from the anticoincidence circuit. The events which one desires to record are of the following type. A mesotron traverses the counters L, A1, and A &, is stopped in the absorber A, and then disintegrates giving rise to an electron which discharges one of counters B.The amplitude of the pulse from the time circuit, as recorded by the pen writing instrument, gives a measure of the life span of the mesotron in the absorber. In addition to the records representing disintegration events, records will be obtained whenever