Lorenzo Cassina

Characterization of the Hamamatsu R11265-103-M64 multi-anode photomultiplier tube

The Hamamatsu R11265-103-M64 MaPMT is the baseline photon sensor to be used for the LHCb RICH Upgrade detector. This choice has been supported by a large number of tests of this device. This note summarizes the measurements performed by the INFN Milano Bicocca group to characterize the photon detector. A description is provided of the unpublished outcomes and particularly of the more recent developments about the aging of the R11265-103-M64 MaPMT and the test of a whole photon detector RICH Elementary Cell.

Characterization of the Hamamatsu H12700A-03 and R12699-03 multi-anode photomultiplier tubes

The H12700 is a novel 64-channel 52

Very low noise AC/DC power supply systems for large detector arrays

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GeFRO: A New Charge Sensitive Amplifier Design for Wide Bandwidth and Closed-Loop Stability Over Long Distances

52 mm

A very low noise and low drift voltage regulator for rare event searches with bolometric detectors

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Radiation Hardness of the CLARO8 ASIC: A Fast Single-Photon Counting Chip for the LHCb Experiment at CERN

square Multi-Anode PhotoMultiplier Tube (MaPMT) produced by Hamamatsu. Its characteristics make this device suitable for high energy physics applications, such as in Ring Imaging Cherenkov (RICH) detectors. Hamamatsu provides the H12700 tube with an embedded socket connecting the anodes to the output pins and including an active voltage divider. A second device version, the R12699, is also available and differs from the former by the absence of the socket. This paper describes a complete characterization of both models, starting from the standard operating parameters (single photon spectra, average gain, anode uniformity and dark current value), investigating in detail the cross-talk effect among neighbouring pixels and considering the behaviour in critical environment conditions, such as in presence of a static magnetic field up to 100 Gauss, at different operating temperatures and after long exposure to intense light.

LHCb RICH Upgrade: an overview of the photon detector and electronic system

In this work, we present the first part of the power supply system for the CUORE and LUCIFER arrays of bolometric detectors. For CUORE, it consists of AC/DC commercial power supplies (0-60 V output) followed by custom DC/DC modules (48 V input, ±5 V to ±13.5 V outputs). Each module has 3 floating and independently configurable output voltages. In LUCIFER, the AC/DC + DC/DC stages are combined into a commercial medium-power AC/DC source. At the outputs of both setups, we introduced filters with the aim of lowering the noise and to protect the following stages from high voltage spikes that can be generated by the energy stored in the cables after the release of accidental short circuits. Output noise is very low, as required: in the 100 MHz bandwidth the RMS level is about 37 μV(RMS) (CUORE setup) and 90 μV(RMS) (LUCIFER setup) at a load of 7 A, with a negligible dependence on the load current. Even more importantly, high frequency switching disturbances are almost completely suppressed. The efficiency of both systems is above 85%. Both systems are completely programmable and monitored via CAN bus (optically coupled).

A fast and radiation-hard single-photon counting ASIC for the upgrade of the LHCb RICH detector at CERN

A new approach was developed for the design of front-end circuits for semiconductor radiation detectors. The readout scheme is a charge sensitive amplifier, split between a very front-end stage (input transistor, feedback resistor and capacitor) located close to the detector and a remote second stage located far from the detector. The element of novelty, with respect to similar configurations, is the fact that the connecting links between the very front-end and the second stage are made with transmission lines. As a result, wide bandwidth and closed-loop stability are maintained even if the distance between the very front-end and the second stage is much larger than usual, up to tens of meters. The circuit was named GeFRO for Germanium front-end, and was tested with a BEGe detector from Canberra. Timing resolutions of 20 ns (open loop) and 185 ns (closed loop with 60 ° phase margin) were obtained with 10 m long cables between the very front-end and the second stage. The noise of the circuit after a 10 μs Gaussian shaping was close to 160 e- RMS with an input capacitance of 26 pF.

A very high performance stabilization system for macro-calorimeter arrays experiments

A linear power supply circuit was designed for long runs with highly sensitive particle physics experiments, such as rare event searches with bolometric detectors. The circuit accepts unregulated power supply voltages up to about ±20 V and gives at the output very low noise, high stability voltages, whose values can be tuned between ±2:5 V and ±11:25 V. The rated current at the output is 4 A. The circuits are protected against failures and shorts at the output with a voltage and a thermal foldback. The recovery time after a short is about 100 μs. The circuit is designed for a thermal drift of 2 ppm=°C and a noise spectrum below 10 nV/√Hz down to 1 Hz. An onboard microcontroller provides monitoring and diagnostics and allows to select the output voltages remotely through a CAN bus.

Radiation hardness tests and characterization of the CLARO-CMOS, a low power and fast single-photon counting ASIC in 0.35 micron CMOS technology

Radiation hardness tests of the CLARO8 ASIC, designed in AMS 0.35micron CMOS technology for the upgrade of the CERN LHCb RICH detectors, are presented, including measurements of total- ionizing dose and single event effects.