Interpretation of large ionization bursts observed at high altitudes in high pressure chambers under thick shields

[摘要] NOTE: Text not renderable in plain ASCII is indicated by [...]. Abstract is included in .pdf document.An attempt is made to explain the ionization bursts containing 400 - 1600 particles observed at high altitudes in high pressure chambers heavily shielded with lead, in terms of short-lived neutral mesons produced by primary protons colliding with shield nuclei; neutral mesons instantly decay into photons which initiate electron cascades in the shield resulting in an ionization burst inside the chamber. The primary interaction is treated by means of a simple model for multiple meson production which assumes constant cross section, complete inelasticity and constant multiplicity throughout the energy region [...] ev; 1/3 of the primary energy is assumed to go into neutral mesons.The contribution of the soft component of high energy air showers is estimated and found to be negligible at all altitudes. An analysis of burst data obtained by Neher and Biehl at three altitudes (307 gm, 616 gm, 1030 gm) then shows that the majority of high altitude bursts can be explained by neutral mesons produced in the primary encounter; but not a negligible fraction must be attributed to secondary collisions. From the data of Neher-Biehl and Fahy mean free paths of 185 [plus or minus] 20 gm in air and 355 [plus or minus] 55 gm in lead are deduced.

[发布机构] University:California Institute of Technology;Department:Physics, Mathematics and Astronomy

[效力级别] ionization bursts

[关键词] Physics;ionization bursts