P. Dorosz

Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

The LHCb detector will be upgraded to make more efficient use of the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov detectors are key components of the LHCb detector for particle identification. In this paper we describe the setup and the results of tests in a charged particle beam, carried out to assess prototypes of the upgraded opto-electronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.

CLARO: an ASIC for high rate single photon counting with multi-anode photomultipliers

The CLARO is a radiation-hard 8-channel ASIC designed for single photon counting with multi-anode photomultiplier tubes. Each channel outputs a digital pulse when the input signal from the photomultiplier crosses a configurable threshold. The fast return to baseline, typically within 25 ns, and below 50 ns in all conditions, allows to count up to 107 hits/s on each channel, with a power consumption of about 1 mW per channel. The ASIC presented here is a much improved version of the first 4-channel prototype. The threshold can be precisely set in a wide range, between 30 ke− (5 fC) and 16 Me− (2.6 pC). The noise of the amplifier with a 10 pF input capacitance is 3.5 ke− (0.6 fC) RMS. All settings are stored in a 128-bit configuration and status register, protected against soft errors with triple modular redundancy. The paper describes the design of the ASIC at transistor-level, and demonstrates its performance on the test bench.

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

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.

Characterization of the 8-channel single-photon counting front-end chip for the upgrade of the LHCb RICH detectors

An 8-channel front-end ASIC has been designed in 0.35 micron CMOS technology for the upgrade of the LHCb RICH detectors at CERN. The chip allows fast single-photon counting up to 40 MHz, with a peaking time of 5 ns and a power consumption of about 1 mW per channel. Results of the characterisation of the first version of the chip are presented, including measurements in the lab with a dedicated test system. Radiation hardness tests are described as well, including measurements of total-ionising dose and single event effects.

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

A new version of the CLARO8 ASIC has been designed in AMS 0.35 μm CMOS technology, based on radiation hardened by design cells, and extensively tested. Results on the complete radiation hardness characterization are presented.

Fully differential charge to time converter and fast shaper readout circuit with gain compensation for SiPM

The implementation of fully differential readout method for Silicon Photomultipliers (SiPM) is presented. The front-end circuit consists of preamplifier with fast shaper and Charge to Time Converter (QTC). The fast shaper generates unipolar pulse. The peaking time for single photoelectron is equal to 3.6ns and the FWHM is 3.8ns. The pulse width of the QTC depends on the number of photons. The gain of SiPM is compensated by moderating the bias voltage. The polarization voltage is adjusted indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The advantage of the algorithm is the possibility to set the bias of each SiPM in the array independently so they all could operate in similar conditions (have similar gain and dark count rate).

Microflow measurements of antibodies fluorescence using Silicon Photomultipliers

The paper presents research made using acquisition system designed and built by the authors. It consists of Silicon Photomultipliers used for fluorescence light detection, integrated circuit dedicated for Silicon Photomultipliers and FPGA board for data acquisition. Moreover, electronic part of the system is integrated with optical section i.e. semiconductor laser, optical filters, microflow structure and optical fibers. Measured substances are passed through Polydimethylsiloxane (PDMS) microflow structure with microchannel of tens of um diameter and that is where optical detection phase takes place. The substance is stimulated by laser light and its fluorescence is being detected by SiPM. Measurements with fluorescence dyes such as sodium fluoresceinate and BD Biosciences CF series indicate sensitivity of the measurement system on the level of single picogram of the dye in ml of the buffer. CF dyes are being mixed with antibodies such as ANTI-NPR in order to measure sensitivity of the system for various concentrations of the antibody. ANTI-NPR is an antibody that reacts with human natriuretic peptide, a substance that can be found in human blood short after excessive heart effort or heart failure. Measurement system is not designed only for NPR antibody but also e.g. myoglobin, troponin and others. That is why not only single antibody has been measured.

Front-end electronics with fast signal shaper for silicon photomultipliers

The paper describes a CMOS Integrated Circuit designed for interfacing a Silicon Photomultiplier (SiPM) in UMC 180 nm technology. It features a full signal processing architecture containing Pole-Zero Cancellation (PZC) circuit, Peak Detector and Hold circuit and Comparators which one of main purposes is the coincidence recognition. Front-end electronics consists of two separate channels one for each SiPM. This along with comparators enables to introduce the coincidence mode to the system. It can be used e.g. for significant reduction of dark current of SiPM in measurement data. The main characteristic of the chip is its fast signal shaping. After the amplification and PZC correction, pulses corresponding to single particles of light detected by SiPM are 20 ns. Moreover, switching time of the comparators used in the circuit is 2 ns. Preliminary results of the chip measurements are presented and the functionality of the chip is also explained.

Bandgap voltage reference and temperature sensor in novel SOI technology

A bandgap voltage reference together with absolute temperature sensor (PTAT) designed in 200 nm SOI technology is presented in this paper. Three slightly different versions were designed to verify the diode models available in the SOI process. For more extensive SOI process study the chip was fabricated on three different substrates. The bandgap reference circuit generates Vref = 1.27 V with 10 mV chip to chip spread. The best bandgap version has temperature coefficient -35 μV/K. Circuit design, simulations and comparison with measured performance are presented.

Low intensity fluorescence light measurements using Silicon Photomultiplier with dedicated front-end ASIC

The paper presents front-end ASIC and measurements of low intensity fluorescence light using Silicon Photomultiplier. Front-end ASIC is dedicated device for amplifying and shaping signals from Silicon Photomultipliers. Measurement method is described. Fluorescence intensity for sodium fluoresceinate and resorufin in different concentrations is presented. Sensitivity limit is studied.