Long term performance stability of silicon sensors
R. Moria, C. Betancourta, S. Kühna, M. Hausera, I. Messmera, A. Hasenfratza, M. Thomasa, K. Lohwasserb, U. Parzefalla, K. Jakobsa
Nuc. Instr. Meth. A.Available online 3 March 2015

Abstract: The HL-LHC investigations on silicon particle sensor performance are carried out with the intention to reproduce the harsh environments foreseen, but usually in individual short measurements. Recently, several groups have observed a decrease in the charge collection of silicon strip sensors after several days, in particular on sensors showing charge multiplication. This phenomenon has been explained with a surface effect, the increase of charge sharing due to the increment of positive charge in the silicon oxide coming from the source used for charge collection measurements. Observing a similar behaviour in other sensors for which we can exclude this surface effect, we propose and investigate alternative explanations, namely trapping related effects (change of polarization), and annealing related effects. Several n-on-p strip sensors, as-processed and irradiated with protons and neutrons up to 5×1015 neq/cm2 have been subjected to charge collection efficiency measurements for several days, while parameters like the impedance have been monitored. The probable stressing conditions have been changed in an attempt to recover the collected charge in case of a decrease. The results show that for the investigated sensors the effect of charge sharing induced by a radioactive source is not important, and a main detrimental factor is due to very high voltage, while at lower voltages the performance is stable.

10µm thin transmissive photodiode produced by ALBA Synchrotron and IMB-CNM-CSIC
Journal of Instrumentation, Volume 10, March 2015, Article C03005
16th International Workshop on Radiation Imaging Detectors
C. Cruz, G. Jover-Manas, O. Matilla, J. Avila, J. Juanhuix, G. Pellegrini, D. Quirion and J. Rodriguez

Abstract: Thin silicon photodiodes are common X-ray beam diagnosis devices at synchrotron facilities. Here we present a new device featuring an extremely thin layer that allows X-ray transmission over 90% for energies above 10 keV. The diode has a radiation-hard silicon junction with silicon dioxide passivation and a protective entrance window. These outstanding features make this device suited for diagnostic applications in X-ray synchrotron beamlines. Hereby preliminary results of X-ray transmission, responsivity and uniformity are presented.

Testbeam studies of pre-prototype silicon strip sensors for the LHCb UT upgrade project using the Alibava System Classic

A. Abba, M. Artuso, S. Blusk, T. Britton, A. Davis, A. Dendek, B. Dey, S. Ely, T. Evans, J. Fu, P. Gandini, F. Lionetto, P. Manning, B. Meadows, R. Mountain, N. Neri, M. Petruzzo, M. Pikies, T. Skwarnicki, T. Szumlak, J.C. Wang

Available online 17 October 2015, pages 244-257


Abstract: The LHCb experiment is preparing for a major upgrade in 2018–2019. One of the key components in the upgrade is a new silicon tracker situated upstream of the analysis magnet of the experiment. The Upstream Tracker (UT) will consist of four planes of silicon strip detectors, with each plane covering an area of about 2 m2. An important consideration of these detectors is their performance after they have been exposed to a large radiation dose. In this paper we present test beam results of pre-prototype n-in-p and p-in-n sensors that have been irradiated with fluences up to /cm2.