Radiation Hardness Studies

Major Canadian Contributors

Université de Montréal: Coordination and Performance of Irradiation Studies for LAr Group

The location of the forward calorimeter (FCAL) near the interaction point, at large pseudorapidity (3 < |η| < 5), causes this detector to be subjected to very high radiation levels with an expected dose of 2300 kGy yr-1 and a neutron fluence of 1.0x1016 cm-2 yr-1. The hadron end-cap calorimeter (HEC) will be exposed to a dose of 12 kGy yr-1 and neutron fluences of 6.1x1014 cm-2yr-1.

These high doses can possibly damage the material and equipment used in these calorimeters. The cryogenic environment necessary for the use of liquid argon as active medium of these calorimeters can enhance this damage. The high radiation dose can also cause out gassing from the material and equipment used in the calorimeters such as alloys used as absorbers, glues and epoxy, material of the readout electronic circuits which in turn can spoil the purity of liquid argon. Purity measurements and signal calculations have indicated that a contamination by a few ppm in the liquid argon is enough to spoil the detection capability of this active medium by reducing the amount of collected charge. Therefore, the radiation hardness and mechanical integrity of components in a high dose at liquid argon temperature must be investigated together with the possible effect of out gassing.

The Canadian collaboration is conducting a major effort in the study of the radiation hardness of the FCAL and HEC that will continue for several years.

source: NSERC 1998 Project Research Description