Studies of SiPM @ Padova Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova Plans & Objectives Characterization of Silicon Photo Multipliers of different manufacturers and geometries: Currents Gain & Efficiency Dark Rate Time resolution Long term stability … Search for the best working point. Comparison of performances. Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova SiPM are very sensitive to temperature  Measurements must be performed in a thermostatic chamber. Range: 10 – 40 °C Precision: 1/16 °C Cooling element (peltier) improvement heating resistor SiPM box Control unit Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova Devices Available Green: measurement done Yellow: not completed Red: tried unsuccessfully Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Devices Characterization Current vs Vbias & Temperature SiPM (FBK) I(V) curves very regular Low and linear T dependence Quite high I (≈ few μA) at working point Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Devices Characterization Current vs Vbias & Temperature MPPC (Hmamatsu): I(V) curves quite “irregular” Higher and non-linear T dependence Lower current (≤ 1 μA) Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Devices Characterization Gain SiPM (FBK) Characteristics very linear, both G(V) and G(T). G(V-Vo) doesn't depend on T (Vo = V @ G=0)  absolute definition of “Working Point” (no gain measurement performed on MPPC up to now) Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova Dark Rates SiPM (FBK) Almost flat vs temperature Dark rate decrease very quickly with threshold, Un solo dispositivo testato “estensivamente” Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Dark Rates Comparisons Moderate dependence on geometry (SiPM50 ≈ SiPM100) MPPC less noisy than SiPM at 1 γ, more noisy at ≥ 2 γ (but a better comparison will require some normalization wrt gain, efficiency etc…) Un solo dispositivo testato “estensivamente” Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Devices Characterization Reverse Current Stability FBK devices show jumps, fluctuations, slow drifts. Impacts on dark rate, gain, device life? Hamamatsu devices seem more stable. Very preliminary results (few devices measured, influence from environment?) Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova CPTA 149-35 I(V) characteristic very regular: stronger T dependence w.r.t. SiPM Quite low reverse current and Dark Rate (comparable to 1mm2 devices) Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova CPTA 149-35 Very good gain Less linear vs T at high T  G(V-Vo) not completely independent from T Perugia 16 June 2009 Flavio Dal Corso INFN-Padova

Flavio Dal Corso INFN-Padova Plans… Radiation hardness studies: next week a single SIPM will be irradiated with ≈ 1 MeV neutron at LNL Works in progress : Characterization of all devices Absolute efficiency measurements Time resolution measurements Electronics optimization : - higher amplification - s/n improvements (studies of charge integrating ADC vs peak sensing ADC) Procurement of FBK devices ≈ 15x15 mm2 (array of 8x8 SiPM, 1.5x1.5 mm2 each, on a single chip) Perugia 16 June 2009 Flavio Dal Corso INFN-Padova