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Thanks to its compact structure, mechanical endurance, and low bias voltage, the silicon photomultiplier (SiPM) can be used in small-size applications which require reduced power consumption. In order to detect the light intensity as low as a single photon, the front-end electronics has to amplify and shape the signal of the photodetector. The low-power design cannot impair the performance of readout electronics or limit the capabilities of the SiPM itself. This paper presents a two-channel integrated circuit (IC) designed in Austria Mikro Systeme CMOS 350-nm technology dedicated for the SiPM-based applications. The input stage is a super-common-gate architecture. Each channel of the IC consists of an amplifier and a peak detector with an offset reduction circuit. The power consumption of the single channel is less than 3 mW from the single voltage supply (3.3 V). Moreover, the number of channels of the IC can be easily increased thanks to small dimensions of the circuit. This paper presents a detailed analysis of the IC including: noise performance with adjustment of the input transistor’s size, transient and dc simulations of the amplifier and the peak detector, and the introduction of a simple offset reduction technique for the peak detector. The measurement results obtained with two SiPM detectors are presented.

The silicon photomultiplier (SiPM) is a semiconductor device the gain of which strongly depends on temperature. When performing precise measurements, the gain has to be kept stable without fluctuations. This paper presents a novel method that estimates the gain of the SiPM based on acquired signals. The method is implemented in FPGA architecture and extends the applicability of SiPM’s gain stabilisation by bias correction. The correction is based on the function: G(V, T) = aT + bV + c (G — gain; T — temperature; V — bias voltage; a, b, c — coefficients representing SiPM model). When coefficients of the specific SiPM have been determined prior to the measurement, the system reads the temperature of the detector and calculates the appropriate bias. However, when the coefficients of the specific SiPM are unknown, the system is capable of calculating them at the time of measurement and applying the bias. This is possible due to the system’s ability to automatically define the gain of the photodetector.

A designer of the front-end electronics for the silicon photomultipliers (SiPM) should take into account unique characteristics of this photodetector. The performance of the front-end should boost the qualities of the SiPM, including its timing performance and internal gain. That is why there is a need to create an electrical model of the SiPM, that in particular would emphasize on the equivalence capacitance of the detector and the shape of the output pulse produced in response to an incident photon [1] . This paper presents a simple model of the SiPM that was created based on the parameters of chosen photodetectors. Afterwards the model was applied to the design process of an integrated circuit (IC). After the fabrication process, the measurements of the IC with the SiPM attached, were compared with their simulation equivalents. The comparison was conducted in terms of the peaking time and the amplitude of the output pulses. The results presented a high level of matching between the simulation model and real behavior of the photodetector. These results can help in designing more advanced, multi-channel front-ends for the SiPMs.

The silicon photomultiplier (SiPM) has advantages that allow it to detect low levels of light intensity in medical, chemical and biological applications; it can also build integrated, portable microfluidic systems. This paper presents a SIPM application designed for the detection of fluorescence of biomarkers. In order to minimise the volume of the tested sample, the measurements were conducted in a microfluidic system. A data acquisition system for the SiPM has been designed consisting of a dedicated application specific integrated circuit (ASIC) required to amplify and shape signals from the photodetector . The application has been designed with the aim of transforming it into a portable device. The detection method chosen in the research is based on flow cytometry and single molecule detection [1] , [2] . Although only a single photodetector was used, the presented applications can be adapted to multi-detector measurements. Initially, the application measured the fluorescence of fluorophores. Afterwards, it was used in the detection of Anti-NPR1 to confirm the effectiveness of the method. The application is not dedicated to a single antigen. It can be applied for the detection of a vast range of biomarkers.

An analysis and comparison of the performance of photon detection methods using a silicon photomultiplier (SiPM) in applications which require fast timings is presented. The front-end circuit enables measurement of the amplitude, charge, width of the pulse from the SiPM (time over threshold) and counting of events. The system was tested by generating light of different intensities where signals tend to pile-up. The signals generated by various numbers of photons are well separated on the single photon spectra. All methods have strong linearity parameters. The amplitude and charge methods are more accurate, have higher r-squared values, lower prediction intervals and higher sensitivity. On the other hand they require a more complicated readout system. The event’s counting and ToT methods have weaker parameters; however the advantage is simpler readout.

The paper presents an implementation of fully differential readout method for Silicon Photomultipliers (SiPM). Front-end electronics consists of a fast and slow path. The former creates the trigger signal while the latter produces a pulse of width proportional to the input charge. The fast shaper generates unipolar pulse and utilizes the pole-zero cancelation circuit. The peaking time for single photoelectron is equal to 3.6 ns and the FWHM is 3.8 ns. The pulse width of the Charge to Time Converter (QTC) depends on the number of photons entering the SiPM at the moment of measurement. The QTC response is nonlinear but it allows us to work with signals in a wide dynamic range. The proposed readout method is effective in measurements of random signals where frequent events tend to pile-up. Thermal generation and afterpulses have a strong influence on the width of pulses from QTC. The proposed method enables us to distinguish those overlapping signals and get the reliable information on the number of detected photons.

The paper presents method for thermal generation reduction in low level light applications, especially where measured phenomena have random character. The algorithm was developed basing on cosmic ray measurements. The main parts of the system are: Silicon Photomultipliers (SiPM), front-end ASIC for amplifying and shaping signals. SiPM is a very sensitive device which can detect single photons. Comparing to a standard photomultiplier SiPM has a compact size, low operating voltage and it is immune to an electromagnetic field. Thermally generated signals are disadvantage of SiPM. This paper presents the measurement method to reduce influence of thermal generation.

The paper stresses the issue of strong temperature influence on the gain of a Silicon Photomultiplier (SiPM). High sensitivity of the detector to light (single photons) requires stable parameters during measurement, including gain. The paper presents a method of compensating the change of gain caused by temperature variations, by adjusting a suitable voltage bias provided by a precise power module. The methodology of the research takes in account applications with a large number of SiPMs (20 thousand), explains the challenges and presents the results of the gain stabilization algorithm.

Gain of the silicon photomultiplier is strongly dependent on the value of bias voltage and temperature. This paper proposes a method for gain stabilization just by compensation of temperature fluctuations by bias correction. It has been confirmed that this approach gives good results and the gain can be kept very stable.

Proposed algorithm compensates the gain by changing the bias voltage of Silicon Photomultipliers (SiPM). The signal from SiPM is amplified in fully differential preamplifier then is formed in time by the fully differential fast shaper. The compensation method was tested with four channels common cathode multi-pixel photon counter from Hamamatsu. The measurement system requires only one high voltage power supply. The polarization voltage is adjusted individually in each channel indirectly by tuning the output common mode voltage (VOCM) of fully differential amplifier. The changes of VOCM affect the input voltage through the feedback network. Actual gain of the SiPM is calculated by measuring the mean amplitude of the signal resulting from detection of single photoelectron. The VOCM is adjusted by DAC so as to reach the desired value of gain by each channel individually. 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 very similar conditions (have similar gain and dark count rate). The algorithm can compensate the variations of gain of SiPM by using thermally generated pulses. There is no need to use additional current to voltage conversion which could introduce extra noises.

Silicon PhotoMultipliers (SiPM) are rapidly approaching a significant maturity stage, making them a well recognised platform for the development of evolutionary and novel solutions in a wide range of applications for research and industry. However, they are still affected by stochastic terms, notably a high Dark Count Rate (DCR), limiting their use when single photo-electron pulses convey the required information, for instance in chemiluminescence or fluorescence analysis of biological samples. In such applications, randomness of the spontaneous generation of carriers triggering the avalanche and the rate of occurrences is significantly decreasing the sensitivity of the system against solutions based, for instance, on traditional photo-multiplier tubes. However, unpredictability of the “dark” pulses has a potential value in domains connected to encryption and, in general terms, cybersecurity. ”Random Power” is a project approved within the ATTRACT call for proposals ( https://attract-eu.com ), having as a main goal the generation of random bit streams by properly analysing the time sequence of the Dark Pulses. The principle has been proven using laboratory equipment and its value assessed applying the National Institute of Standard and Technology (NIST) protocols, complemented by other test suites. The advantages against competing techniques have been thoroughly analysed and the development of a dedicated board, integrating the system in a low cost, low power, scalable design is on-going. The principle, protected by a patent application entered its international phase by the time of writing (application no.102018000009064, deposited at the Office of the Minister of Economic Development, as required by the Italian law; international PCT extension no.PCT/IB2019/058340 deposited in October 2019) will be described, together with the results obtained so far, the current development stage including an FPGA embedded Time-To-Digital Converter (TDC) and future perspectives.