T. Cervi

Realization of a high vacuum evaporation system for wave-length shifter deposition on photo-detector windows

In this paper, the authors present a system based on a vacuum chamber and Knudsen cells that can evaporate organic materials on convex surfaces up to 10 in. diameter, with a good uniformity, in a very short time. This system was successfully used at CERN for the deposition of tetra-phenyl butadiene wavelength shifter on the 8 in. window of 360 Hamamatsu R5912-MOD photomultiplier tubes (PMTs), before their installation inside the ICARUS T600 detector to be used for neutrino physics studies. The quantum efficiency in the vacuum ultraviolet region measured on the whole photocathode shows a good uniformity over the entire PMT active surface with an average value above 10% from 120 to 200 nm.

Study of SiPM custom arrays for scintillation light detection in a Liquid Argon Time Projection Chamber

Liquid Argon Time Projection Chamber (LAr-TPC) technique has been established as one of the most promising for the next generation of experiments dedicated to neutrino and rare-event physics. LAr-TPCs have the fundamental feature to be able to both collect the charge and the scintillation light produced after the passage of a ionizing particle inside the Argon volume. Scintillation light is traditionally detected by large surface Photo-Multiplier Tubes (PMTs) working at cryogenic temperature. Silicon Photo-Multipliers (SiPMs) are semiconductor-based devices with performances comparable to the PMT ones, but with very small active areas. For this reason we built a prototype array composed by SiPMs connected in different electrical configurations. We present results on preliminary tests made with four SiPMs, connected both in parallel and in series configurations, deployed into a 50 liters LAr-TPC exposed to cosmic rays at CERN.

Mass test of AdvanSiD model ASD-NUV3S-P SiliconPMs for the Pixel Timing Counter of the MEG II experiment

The MEG II Timing Counter will measure the positron time of arrival with a resolution of 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD. They must be characterized, measuring their breakdown voltage, to assure that the gains of the SiPMs of each pixel are as uniform as possible, to maximize the pixel resolution. To do this an automatic test system that can measure sequentially the parameters of 32 devices has been developed.

Radiation Hardness tests with neutron flux on different Silicon photomultiplier devices

Radiation hardness is an important requirement for solid state readout devices operating in high radiation environments common in particle physics experiments. The MEGII experiment, at PSI, Switzerland, investigates the forbidden decay

Laboratory tests for X-rays crystal detectors with SiPM array readout

\mu^+ \to \mathrm{e}^+ \gamma

Radiation hardness tests with neutrons of timing counter MEGII SiPMs

. Exploiting the most intense muon beam of the world. A significant flux of non-thermal neutrons (kinetic energy

Characterization of AdvanSiD and hamamatsu SiPMs for novel design cryogenic detectors

E_k\geq 0.5 ~MeV

Test and characterization of 20 pre-series hamamatsu R5916-MOD photomultiplier tubes for the ICARUS T600 detector

) is present in the experimental hall produced along the beamline and in the hall itself. We present the effects of neutron fluxes comparable to the MEGII expected doses on several Silicon PhotoMulitpliers (SiPMs). The tested models are: AdvanSiD ASD-NUV3S-P50 (used in MEGII experiment), AdvanSiD ASD-NUV3S-P40, AdvanSiD ASD-RGB3S-P40, Hamamatsu and Excelitas C30742-33-050-X. The neutron source is the thermal Sub-critical Multiplication complex (SM1) moderated with water, located at the University of Pavia (Italy). We report the change of SiPMs most important electric parameters: dark current, dark pulse frequency, gain, direct bias resistance, as a function of the integrated neutron fluency.

Comparison between large area photo-multiplier tubes at cryogenic temperature for neutrino and rare event physics experiments

The use of new PrLuAg and Ce:CAAG crystals, developed for PET scanners. and of more conventional LaBr3 crystals, with a SiPM array readout has been proposed, searching for compact X-rays detectors. The first two crystals are not-hygroscopic and have high photon yields, good energy resolution and fast decay time. Preliminary laboratory results are reported.

Characterization of SiPM arrays with common bias and common readout for applications in liquid argon

The MEGII Timing Counter will measure the positron time of arrival with a resolution of 30 ps relying on two arrays of scintillator pixels read out by 6144 Silicon Photomultipliers (SiPMs) from AdvanSiD.