119265780
Ionization signals from electrons and alpha-particles in mixtures of liquid Argon and Nitrogen – perspectives on protons for Gamma Resonant Nuclear Absorption applications
In this paper we report on a detailed study of ionization signals produced by Compton electrons and alpha-particles in a Time Projection Chamber (TPC) filled with different mixtures of liquid Argon and Nitrogen. The measurements were carried out with Nitrogen concentrations up to 15% and a drift electric field in the range 0-50 kV/cm. A prediction for proton ionization signals is made by means of interpolation. This study has been conducted in view of the possible use of liquid Ar−N2 TPCs for the detection of gamma-rays in the resonant band of the Nitrogen absorption spectrum, a promising technology for security and medical applications.
122307837
First measurements with ARGONTUBE, a 5m long drift Liquid Argon TPC
Abstract The Liquid Argon Time Projection Chamber (LAr TPC) technique is a promising technology for future neutrino detectors. At LHEP of the University of Bern (Switzerland), an R&D program towards large detectors are on-going. The main goal is to show the feasibility of long drift paths over many meters. Therefore, a liquid Argon TPC with 5 m of drift distance was constructed. Many other aspects of the liquid Argon TPC technology are also investigated, such as a new device to generate high voltage in liquid Argon (Greinacher circuit), a recirculation filtering system and the multi-photon ionization of liquid Argon with a UV laser. Two detectors are built: a medium size prototype for specific detector technology studies, and ARGONTUBE, a 5 m long device.
122227593
Evidence for x Rays From Sources Outside the Solar System
Data from an Aerobee rocket carrying three large-area geiger counters have revealed a considerable flux of radiation in the night sky. Analysis of these data indicates the bulk of the radiation is soft x rays from sources outside the solar system. Synchrotron radiation by cosmic electrons is a possible mechanism for the production of these x rays. Ordinary stellar sources could also contribute a considerable fraction of the observed radiation. (H.D.R.)
121123430
Cosmic-Ray Air Showers at Sea Level
272273
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
120635227
Cosmic-Ray Theory
124758213
The Variation of the Hard Component of Cosmic Rays With Height and the Disintegration of Mesotrons