Mr Davide Fiorina (INFN & Università di Pavia)Mr Simone Calzaferri (Università degli Studi di Pavia)
In order to extend previous studies and test additional variables playing a role in the aging processes, a Single Wire Proportional Chamber (SWPC) was specially designed. In this contribution, the authors will present the result of two couples of tests performed on this SWPC. During the first test, the SWPC was irradiated with X-rays and alpha particles sources with the same hit rate until the same integrated charge (1.4 mC/cm) was reached. Nevertheless, the performance loss during the X-ray irradiation was larger, traces of polymers were found on the wire only in the case of alpha irradiation. The second test was performed irradiating the SWPC with alphas and X-ray, but this time with the same anodic current i.e. very different hit rate. The irradiation continued until the wire chamber lost half of the initial gas gain. As expected, in the case of alpha irradiation the integrated charge needed for the goal was lower with respect to the one needed during the X-ray radiation: 9.5 mC/cm and 33 mC/cm respectively. However, the electron microscope analysis revealed, once again, a large polymer deposit on the alpha irradiated wire while no deposit was found on the X-ray irradiated one.
Mr Davide Fiorina (INFN & Università di Pavia)