Search

The production cross section of 30.92 GeV/c protons on carbon is measured by the NA61/SHINE spectrometer at the CERN SPS by means of beam attenuation in a copy (replica) of the 90-cm-long target of the T2K neutrino oscillation experiment. The employed method for direct production cross-section estimation minimizes model corrections for elastic and quasi-elastic interactions. The obtained production cross section is σ$_{prod}$ = 227.6 ± 0.8(stat)$\frac{+1.9}{−3.2}$(sys) − 0.8(mod) mb. It is in agreement with previous NA61/SHINE results obtained with a thin carbon target, while providing improved precision with a total fractional uncertainty of less than 2%. This direct measurement is performed to reduce the uncertainty on the T2K neutrino flux prediction associated with the re-weighting of the interaction rate of neutrino-yielding hadrons.

Pentaquark states have been extensively investigated theoretically in the context of the constituent quark model. In this paper results of an experimental search for pentaquarks in the Ξ- π-, Ξ- π+, Ξ¯+ π- and Ξ¯+ π+ invariant mass spectra in proton-proton interactions at s=17.3 GeV are presented. Previous possible evidence from the NA49 collaboration of the existence of a narrow Ξ- π- baryon resonance in p+p interactions is not confirmed with almost 10 times greater event statistics. The search was performed using the NA61/SHINE detector which reuses the main components of the NA49 apparatus. No signal was observed with either the selection cuts of NA49 or newly optimized cuts.

Recenzja książki: Etnomuzykologia na przełomie tysiącleci: historia, teoria, metodologia / Етномузикологія на зламі тисячоліть: історія, теорія, методологія), red. Zbigniew Jerzy Przerembski, Wrocław 2015

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.

Precise knowledge of hadron production rates in the generation of neutrino beams is necessary for accelerator-based neutrino experiments to achieve their physics goals. NA61/SHINE, a large-acceptance hadron spectrometer, has recorded hadron+nucleus interactions relevant to ongoing and future long-baseline neutrino experiments at Fermi National Accelerator Laboratory. This paper presents three analyses of interactions of 60 GeV/$c$ $\pi^+$ with thin, fixed carbon and beryllium targets. Integrated production and inelastic cross sections were measured for both of these reactions. In an analysis of strange, neutral hadron production, differential production multiplicities of $K^0_{S}$, $\Lambda$ and anti-$\Lambda$ were measured. Lastly, in an analysis of charged hadron production, differential production multiplicities of $\pi^+$, $\pi^-$, $K^+$, $K^-$ and protons were measured. These measurements will enable long-baseline neutrino experiments to better constrain predictions of their neutrino flux in order to achieve better precision on their neutrino cross section and oscillation measurements.

This paper presents measurements of production cross sections and inelastic cross sections for the following reactions: 60 GeV/c protons with C, Be, Al targets and 120 GeV/c protons with C and Be targets. The analysis is performed using the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. First measurements are obtained using protons at 120 GeV/c, while the results for protons at 60 GeV/c are compared with previously published measurements. These interaction cross section measurements are critical inputs for neutrino flux prediction in current and future accelerator-based long-baseline neutrino experiments.

This paper presents an application for single molecule detection based on the silicon photomultiplier (SiPM). The research methodology uses the principles of fluorescence measurement. Single molecule detection enables reducing the required volume of the measured sample by a considerable degree. This allows the study of complex reaction mechanisms, rare events, or subpopulations of complex biomolecules such as DNA or proteins whose individual properties are often hidden in conventional ensemble-based measurements. This paper describes a complete readout system designed for fluorescence detection. The system consists of a SiPM with a dedicated application-specific integrated circuit, and a software application for saving and evaluating data. Aside from the electronics, the readout is equipped with an optical system (a laser diode, a band-pass optical filter and a µ-Slide plate). The system has been applied to the fluorescence detection of fluorophores. The obtained results provide the basis for performing fluorescence measurements of single cells in a multi-spot optical system. The calibration of the system has been performed with the use of fluorescent cytometer dye.

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.

Paper presents the detection method of the chemiluminescence phenomenon using SiPM. Chemiluminescence phenomena is kind of luminescence which appears as a results of a chemical reaction and is used in many applications in a medicine, chemistry, biology, biotechnology, environmental protection. The readout electronics requires to measure a single photons and should be fast to distinguish overlapping signals generated by the chemiluminescence light. The front-endelectronics consists of preamplifier and fast shaper. It produces the pulses which peaking time for the single photon is equal to 3.6 ns and the FWHM is 3.8 ns. The performance of the detection method was verify with measurements of the chemiluminescence of luminol (it is used i.e.in the criminology to detect the traces of blood). The system is optimal to measure chemiluminescence. It generates low number of overlapping pulses and is accurate. The relationship between the light intensity and concentration of luminol is linear and have high r-squared parameter equal to 0.9995 and low 95% prediction intervals.

Measurements of inclusive spectra and mean multiplicities of $\pi^\pm$, K$^\pm$, p and $\bar{\textrm{p}}$ produced in inelastic p+p interactions at incident projectile momenta of 20, 31, 40, 80 and 158 GeV/c ($\sqrt{s} = $ 6.3, 7.7, 8.8, 12.3 and 17.3 GeV, respectively) were performed at the CERN Super Proton Synchrotron using the large acceptance NA61/SHINE hadron spectrometer. Spectra are presented as function of rapidity and transverse momentum and are compared to predictions of current models. The measurements serve as the baseline in the NA61/SHINE study of the properties of the onset of deconfinement and search for the critical point of strongly interacting matter.

We present measurements of $\rho^0$, $\omega$ and K$^{*0}$ spectra in $\pi^{-} + $C production interactions at 158 GeV/c and $\rho^0$ spectra at 350 GeV/c using the NA61/SHINE spectrometer at the CERN SPS. Spectra are presented as a function of the Feynman's variable $x_\text{F}$ in the range $0 < x_\text{F} < 1$ and $0 < x_\text{F} < 0.5$ for 158 GeV/c and 350 GeV/c respectively. Furthermore, we show comparisons with previous measurements and predictions of several hadronic interaction models. These measurements are essential for a better understanding of hadronic shower development and for improving the modeling of cosmic ray air showers.

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.

A readout circuit dedicated for the detection of the chemiluminescence phenomenon using a silicon photomultiplier (SiPM) is presented. During chemiluminescence, light is generated as a result of chemical reaction. Chemiluminescence is used in many applications within medicine, chemistry, biology and biotechnology, and is one of the most important sensing techniques in biomedical science and clinical medicine. The front-end electronics consist of a preamplifier and a fast shaper—this produces pulses, the peaking time which is 3.6 ns for a single photon and the FWHM is 3.8 ns. The system has been optimised to measure chemiluminescence—it is sensitive at the level of single photons, it generates a low number of overlapping pulses and is accurate. Two methods of signal detection are analysed and compared: the counting of events and amplitude detection. The relationship between the chemiluminescence light intensity and the concentration of the chemical compound (luminol) is linear in the range of the tested concentrations and has strong linearity parameters and low prediction intervals.

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).

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.

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.

The paper presents radiation tolerance of the transistor TEG (TrTEG5) test structure fabricated in 200 nm fully depleted silicon on insulator technology dedicated to production of SOI detectors. The chip was irradiated with 60Cobalt gamma-ray source to total dose of 1.175 kGy at a rate of 67.8 Gy/h. During irradiation, current-voltage characteristics of seventeen different transistors were measured so as to investigate factors affecting radiation resistance. Transistors' threshold voltage shift and transconductance change as a function of the deposited dose are presented. After irradiation all transistors manifested correct operation and threshold voltage change of around 200 mV fall within the limits of specified technological mismatch.

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.

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.

A digital library designed in 200 nm fully depleted silicon on insulator (FD-SOI) technology is presented in this paper. For the purpose of a new technology the digital library containing 93 elements was designed. Created library allows automatic synthesis of digital blocks based on their description in hardware description languages (HDL). To preserve area occupied by each library element, height of 7.68 μm was chosen for all layout cells. The paper presents designed digital library., compares its performance with digital library made in Austria Mikro Systeme (AMS) 0.35 μm and shows test structures' measurements results.

Charged particle multiplicities are studied in proton-proton collisions in the forward region at a centre-of-mass energy of $\sqrt{s} = 7\;$TeV with data collected by the LHCb detector. The forward spectrometer allows access to a kinematic range of $2.0

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.

Performance of Silicon Photomultipliers (SiPM) [1] strongly depends on bias voltage and temperature. The key aspect in low light detection is precision and stability of SiPMs gain. These requirements can be met by delivering accurate bias and keeping temperature on constant level. It is not very demanding task in case of single SiPM. However, in applications consisting of thousands of SiPMs it is much more problematic or even impossible to control the temperature of each detector (e.g. nuclear physics experiments). The paper presents a gain stabilization method that can be applied in multidetector measurements without the need to characterize gain-temperature-bias functions and parameters of all detectors used in the experiment.