Modeling high impedance connecting links and cables below 1 Hz

High impedance connecting links and cables are modeled at low frequency in terms of their impedance to ground and to neigbouring connecting links. The impedance is usually considered to be the parallel combination of a resistance and a capacitance. While this model is adequate at moderate and low frequency, it proved to be not satisfactory at very low frequency, in the fractions of Hz range. Deep characterization was carried out on some samples down to 10 uHz, showing that an additional contribution to capacitance can emerge. A model was developed to explain and account for this additional contribution

CLARO-CMOS, a very low power ASIC for fast photon counting with pixellated photodetectors

The CLARO-CMOS is an application specific integrated circuit (ASIC) designed for fast photon counting with pixellated photodetectors such as multi-anode photomultiplier tubes (Ma-PMT), micro-channel plates (MCP), and silicon photomultipliers (SiPM). The first prototype has four channels, each with a charge sensitive amplifier with settable gain and a discriminator with settable threshold, providing fast hit information for each channel independently. The design was realized in a long-established, stable and inexpensive 0.35 um CMOS technology, and provides outstanding performance in terms of speed and power dissipation. The prototype consumes less than 1 mW per channel at low rate, and less than 2 mW at an event rate of 10 MHz per channel. The recovery time after each pulse is less than 25 ns for input signals within a factor of 10 above threshold. Input referred RMS noise is about 7.7 ke^- (1.2 fC) with an input capacitance of 3.3 pF. Thanks to the low noise and high speed, a timing resolution down to 10 ps RMS was measured for typical photomultiplier signals of a few million electrons, corresponding to the single photon response for these detectors

First characterization of the Hamamatsu R11265 multi-anode photomultiplier tube

The characterization of the new Hamamatsu R11265-103-M64 multi-anode photomultiplier tube is presented. The sample available in our laboratory was tested and in particular the response to single photon was extensively studied. The gain, the anode uniformity and the dark current were measured. The tube behaviour in a longitudinal magnetic field up to 100 G was studied and the gain loss due to the ageing was quantified. The characteristics and performance of the photomultiplier tube make the R11265-103-M64 particularly tailored for an application in high energy physics experiments, such as in the LHCb Ring Imaging Cherenkov (RICH) detector at LHC

A multichannel data acquisition system for bolometer detectors based on microcontroller Cortex M3 architecture

We present the first prototype of a custom Data Acquisition System for bolometer and scintillating bolometer detectors. It consists of a board controlled by a Cortex M3 microcontroller coupled with a 8 channels Sigma/Delta 24 bit ADC. The large number of bits allows having at the same time a high dynamic and a high resolution at low threshold, in order to separate very low energy events. Each board accommodates 8 input channels sampled simultaneously with a maximum rate of 50 kHz. Converted data are read by the microcontroller and sent to the remote controller using the TCP/IP or UPD communications protocol. The microcontroller also manages the board configuration. The board, exploiting the microcontroller flexibility, is fully programmable, it can work in different running modes and it can perform common data processing algorithms on the acquired data (first level trigger, digital filtering, zero suppression, FFT, etc). In this work we present tests and characterizations about this first custom data acquisition system. The results are the starting point in order to design the final prototype. © 2012 IEEE