DETECTORES Mercedes 16 5 2008 About the simulations

DETECTORES Mercedes 16 -5 -2008

About the simulations… • The detector simulations at normal operation do not show differences in both configurations (diode & strips) Te l a c i chn m e l b Pro

With no dependence on the configuration • The instantaneous current induced on electrode A can be expressed in terms of a weighting field Ew: Assume that a charge, q, is created in a detector: i. A = q V Ew(x) Ramo Theorem Where V is the charge’s velocity: V = m E(x) • A e-h pair is formed at coordinate x, the charge induced : Qe = i. Ae tce = q Ve Ew x /Ve = q x/d d : detector thickness Ew = 1 /d Qh = i. Ah tch = q Vh Ew (d-x) /Vh = q (1 - x/d) Qe + Qh = q … t u B Due to different mobilities, at a same time lower than the • collection time: Qe + Qh < q • So, if the integration time is larger than the collection time of all charge carriers, the measured charge will be the full charge. A shorter integration time yields a fractional charge

• The effect of the different configurations must be observed in the shape pulse, not in the collected charge (if the collection time is large enough): LAB TEST: (To Do) Diode Configuration Red Laser Strip Configuration

• Simulate a silicon substrate with three electrodes and other one in the backplane to calculate the weighting fields associate to an electrode connected at unit potential. 1. Diode Configuration (three electrodes as just one at 1 V) 2. Strip Configuration (central electrode at 1 V) 2.

Diode Configuration

Strip Configuration

About the real detectors… • Start measuring RD 50 irradiated microstrip detectors with the ALIBAVA system. (probe the ALIBAVA system at low temperature) • Waiting ATLAS 07 irradiated microstrip detectors