Micropixel Avalanche Photodiodes Research Articles

Neutron/gamma scintillation detector for status monitoring of accelerator-driven neutron source IREN

This paper presents a neutron/gamma detector based on a micropixel avalanche photodiode and a plastic scintillator that monitors the status of the accelerator-driven intense resonance neutron source (IREN) facility by measuring the neutron/gamma intensity in the target hall. The electronics of the neutron/gamma detector has been designed and developed. The size of the plastic scintillator was selected to be 3.7 × 3.7 × 30 mm3 due to the sensitive area of the MAPD. The experimental results demonstrated a dependence between the count rate of the detector and the frequency of the accelerator. The detector is sensitive to intermediate and fast neutrons. The minimum detectable energy was determined to be 200 keV using Cs-137 point gamma source. The maximum counting rate of the detector from TTL out is about 2.2·106 counts/sec, but for analogue output it is about 2·107 counts/sec. The detector can not allow discriminating neutrons and gamma rays by charge integration method.

Study of low-energy gamma-ray detection performance of silicon photomultiplier with LaBr3(Ce) scintillator

Recent progress in the field of scintillators and silicon photomultipliers (SiPM) has allowed development of new scintillation detectors capable of detecting low-energy X- and gamma-ray sources that are widely used in medicine, security and industry. Such scintillation detectors are compact, insensitive to magnetic fields, have low operation voltages and are functional at room temperature. These advantages of SiPM are considered to solve the main problems facing scintillation detectors in medicine and industry today. Development of detectors of low-energy electromagnetic radiation is relevant now. Scintillation detectors based on lutetium fine silicate, LaBr3(Ce), NaI and silicon avalanche photomultipliers offer a great potential for use for X- and gamma-ray detection. The present work demonstrates the gamma-ray detection performance of a new micropixel avalanche photodiode (MAPD) array (16 (4×4) elements – 15×15 cm) with a LaBr3(Ce) scintillator (15×15×30 mm) using 177Lu and 133Ba isotopes as the gamma-ray sources.

Investigation of gamma-ray sensitivity of YAG:Ce based scintillation structures

Ionizing radiation is widely used nowadays for diagnosing and probing a wide range of objects due to the high reliability and quality of the results obtained in such research. Use of highly sensitive ionizing radiation sensors enables the reduction of the radiation dose involved in the research. Moreover, sensitive systems for monitoring environmental parameters may be also created based on such sensors. In this work, the efficiency of a low density radiation detector with the composite scintillation structure based on powdery YAG:Ce phosphor as the converting coating of photosensitive detector was investigated. The possibility to detect gamma radiation from the 241 Am and 137 Cs based sources by the ionizing radiation detector comprising YAG:Ce 3+ composite converting scintillation structure and micropixel avalanche photodiode (MAPD) was found. The number of detected gamma rays emitted by the 241 Am source was shown to increase linearly with the thickness of the composite converting scintillation structure. The thickness of the composite converting scintillation structure of 495 µm was found to enable registration of gamma-rays with the energies in the range of 26 to 662 keV.

Improvement of parameters of micro-pixel avalanche photodiodes

The paper is concerned with the parameter study of a new generation of micro-pixel avalanche photodiodes (MAPD) with deeply buried pixel structure, also named silicon photomultipliers (SiPM) or multi-pixel photon counter (MPPC). The new MAPD of type MAPD-3NM was manufactured in the frame of collaboration with Zecotek Company. Measurements were carried out and discussed in terms of the important parameters such as the current-voltage and capacitance-voltage characteristic, gain, the temperature coefficient of breakdown voltage, breakdown voltage, and gamma-ray detection performance using an LFS scintillator. The obtained results showed that the newly developed MAPD-3NM photodiode outperformed the previous generation in most parameters and can be successfully applied in space application, medicine, high-energy physics, and security. New proposals are also discussed, for further improvement of the parameters of the MAPD photodiodes that will be produced in the coming years.

Application features of micro-pixel avalanche photodetectors in the laser Doppler anemometers

The optical receiver is an essential part of any laser Doppler anemometer. Traditionally, vacuum photomultiplier tubes are used for reliable reception of weak optical radiation. However, this type of photodetector has its own drawbacks, which lead to a design complication and an increase in the cost of LDA. In this work, the characteristics of silicon micropixel avalanche photodiodes are investigated and the operation of a silicon photomultiplier as a photodetector in an LDA is tested when measuring the velocity on test benches. The possibility of using Si-PMT to receive optical signals of the laser Doppler anemometer is shown.

Gamma-ray spectroscopy with MAPD array in the readout of LaBr3:Ce scintillator

This paper presented a new detector module consisting of a micropixel avalanche photodiode (MAPD-3NM), LaBr3:Ce scintillator, and a compact read-out interface system for detecting gamma-rays in a wide energy range. The MAPD array (4 × 4 channels) was assembled using a single MAPD-3NM characterized by its high photon detection efficiency (∼25%), pixel density (10 000 pixels/mm2), low operation voltage (74.5 V), and low dark current. An active area of a single MAPD-3NM was 3.7 × 3.7 mm2, while this value was 17 × 17 mm2 for the assembled array with pixel density of 2190 000. The size of the tested LaBr3:Ce scintillator was 15 × 15 × 15 mm3. According to the characteristics of the detector module, a compact read-out interface device (SPECTRIG MAPD) was developed. SPECTRIG MAPD was designed as a miniature device with low power consumption, which continues to provide a wide spectrum of functions needed for measurement and test silicon photomultipliers (SiPM) and scintillation detectors on their basis. The various experiments were implemented to test the detection performance of a detector module to gamma radiation in the range from 30 keV to 4400 keV.

Miniaturized read-out interface “Spectrig MAPD” dedicated for silicon photomultipliers

The new pocket size read-out interface device dedicated for silicon photomultipliers (SiPM) has been designed and developed. While it was designed as a miniaturized and low power device it still provides a wide spectrum of functionality necessary for measurements and testing of SiPMs and SiPM based detectors. Full signal processing has been integrated within the device involving variable gain amplification, filtration and digitization. Signal acquisition can be performed with sampling frequency 400 MSa/s at 12 bit resolution or 600 MSa/s at 8 bit resolution while achieving full waveform capture & download rate about 20 000 events per second. The read-out interface is fully powered from the USB bus allowing operation without need of additional power line connection. An integrated bias source can be set in range from 0V to +200V with 12 bit precision. The read-out interface is primarily dedicated for spectroscopy purposes. There are two input signal channels with different optimization regarding the signal gain to cover a low energy range corresponding to single photo-electron detector response as well as to cover a high energy range corresponding to a detector response operated with scintillator registering gamma radiation in order of MeVs. Both input channels are equipped with fine gain adjustment in range from -9 dB to 26 dB with 1 dB step in addition to the fixed gain of each signal channel. The FPGA based design of the read-out interface allowed implementation of advanced triggering functionality like a data driven trigger, external trigger, gating of trigger to extend read-out interface capability even further in a way of complex experiments. A set of functional tests and experiments with SiPM called micropixel avalanche photodiode (MAPD) and MAPD based detectors have been performed to characterize real properties of the read-out interface.

Scintillation readout with MAPD array for gamma spectrometer

In this study, we present the gamma-ray detection performance of LYSO, YSO(Ce) and BGO scintillators read out by a 9 ch. micropixel avalanche photodiode (MAPD) array with a high pixel density (PD) and photon detection efficiency (PDE). The array with an active area of 11.5 × 11.5 mm2 was assembled using single MAPDs with an active area of 3.7 × 3.7 mm2. It had a single output signal and was developed for gamma spectroscopy. Breakdown voltage measurements were carried out for each channel, as a result of which the optimal operating voltage for the array was found. The linearity range and energy resolution for each crystal were determined in the energy range from 30 to 1770 keV . The high pixel density of the array allowed to achieve good linearity in the studied energy range.

Influence of Background Illumination on the Photoresponse of Micropixel Avalanche

Micropixel avalanche photodiodes (MAPD) with deeply buried pixels have no structural components made on its front surface and therefore almost its entire surface is photosensitive. MAPD possesses high photodetection efficiency (PDE), multiplication gain ~105, photosensitivity from a single photon and wide range of dynamic linearity of photoresponse up to 5×103 photons/mm2. The influence of the background light on the gain and linearity of the photoresponse of the MAPD-3N type samples was investigated. External light sources have different effects on the output signal of MAPD whichever it is pulsed or continuous light. It is shown that in contrast to pulsed external light, the light from the permanent source leads to reducing of the output signal. But a constant background light does not deteriorate the linearity of the photoresponse in the whole range of linearity of the device.

Influence of Background Illumination on the Photoresponse of Micropixel Avalanche

Micropixel avalanche photodiodes (MAPD) with deeply buried pixels have no structural components made on its front surface and therefore almost its entire surface is photosensitive. MAPD possesses high photodetection efficiency (PDE), multiplication gain ~105, photosensitivity from a single photon and wide range of dynamic linearity of photoresponse up to 5×103 photons/mm2. The influence of the background light on the gain and linearity of the photoresponse of the MAPD-3N type samples was investigated. External light sources have different effects on the output signal of MAPD whichever it is pulsed or continuous light. It is shown that in contrast to pulsed external light, the light from the permanent source leads to reducing of the output signal. But a constant background light does not deteriorate the linearity of the photoresponse in the whole range of linearity of the device.

Negative Capacitance on Silicon Avalanche Photodiodes with Deeply Buried Micropixels

There have been investigated reactive properties of silicon avalanche photodiodes (MAPD- Micropixel Avalanche Photodiode) with deeply buried micropixels (amplification channels) within AC signal frequencies f= (50-500) kHz.By experiment is found out that measured capacitance of structures involving three p-n junctions in section passing through the pixels increases exponentially with Ufor (negative potential is applying to n-Si substrate) reaches maximum and at certain value Ufor= Uinv changes the sign becoming the negative capacitance (equivalent inductance).The magnitude of active component of complete conduction G grows with the applied voltage and reaches maximum value ~70 mS at Ufor= 1,0 V (f=500 kHz). There has been calculated difference in phase j appearing between current and voltage and it is shown that at Ufor=0 V the j = 80o and passes through the zero at Ufor = 0,55 V. The magnitude of negative capacitance recalculated to the inductance value with the growth of forward bias being decreased sharply tends to the saturation.

Negative Capacitance on Silicon Avalanche Photodiodes with Deeply Buried Micropixels

There have been investigated reactive properties of silicon avalanche photodiodes (MAPD- Micropixel Avalanche Photodiode) with deeply buried micropixels (amplification channels) within AC signal frequencies f= (50-500) kHz.By experiment is found out that measured capacitance of structures involving three p-n junctions in section passing through the pixels increases exponentially with Ufor (negative potential is applying to n-Si substrate) reaches maximum and at certain value Ufor= Uinv changes the sign becoming the negative capacitance (equivalent inductance).The magnitude of active component of complete conduction G grows with the applied voltage and reaches maximum value ~70 mS at Ufor= 1,0 V (f=500 kHz). There has been calculated difference in phase j appearing between current and voltage and it is shown that at Ufor=0 V the j = 80o and passes through the zero at Ufor = 0,55 V. The magnitude of negative capacitance recalculated to the inductance value with the growth of forward bias being decreased sharply tends to the saturation.

The beam test of muon detector parameters for the SHiP experiment at CERN

Scintillation detectors based on extruded plastics have been tested in a 10 GeV/c beam at CERN. The scintillation signal readout was provided using optical wavelength shifting fibers Y11 Kuraray and Hamamatsu MPPC micropixel avalanche photodiodes. The light yield was scanned along and across the detectors. Time resolution was found by fitting the MPPC digitized pulse rise and other methods.

Performance of a new generation of micropixel avalanche photodiodes with high pixel density and high photon detection efficiency

Performance of a new generation of micropixel avalanche photodiodes of MAPD-3NK type from Zecotek Photonics as a function of the bias voltage has been studied at the temperature range from –116 °C to 20 °C. The temperature coefficient of the breakdown voltage for this device is 58 ± 3mV/∘C. Photon detection efficiency of the MAPD-3NK has been compared with that of a similar device (serial number: S12572-010P) from Hamamatsu Photonics at the temperature of –27 °C. Both photodiodes have the same pixel density of 10,000 pixel/mm2. The photon detection efficiency of 5 ± 0.3% and 40 ± 2% was measured at the same overvoltage of 3 V for the S12572-010P and the MAPD-3NK, respectively.

On iterative model of performance of micropixel avalanche photodiodes

This paper was devoted to the experimental verification of results of the iterative model for micropixel avalanche photodiodes. The avalanche processes initiated by single-photoelectron were studied for single-pixel avalanche photodiodes from two different manufacturers. It was found that the effective capacitance of the pixel calculated from the experimental charge–bias voltage dependence exceeds its terminal capacitance by a factor of two only at low values of resistance of the depletion region, while the maximum voltage drop on the pixel just after quenching of avalanche process equals twice the value of bias overvoltage. At high values of resistance of the depletion region, the voltage drop on the pixel equals the value of bias overvoltage and therefore the gain of the device is effectively reduced by a factor of two.

New gamma detector modules based on micropixel avalanche photodiode

In this paper presented the results of the ionizing radiation detector modules, which developed on the basis of a new generation of micropixel avalanche photodiode (MAPD) of MAPD-3NK type. The samples were produced in cooperation with the Zecotek Photonics and characterized by the following parameters: sensitive area—3.7 mm × 3.7 mm, density of pixels—10000 pixels/mm2, photon detection efficiency—35–40% (at wavelength of 450–550 nm) and operation voltage—91 V. The beta particle and gamma ray detection performance of MAPD with different single scintillation crystal such as NaI, LFS and p-terphenyl was investigated. The gamma ray detector modules demonstrated a perfect linear behavior of detected signal amplitudes as a function of the gamma ray energy (from 26.3 keV up to 1.33 MeV). Energy resolution for 662 keV gamma rays was 11.2% and the minimum detectable energy was 26.3 keV.

The design of the TASD (totally active scintillator detector) prototype

Totally active and magnetic segmented scintillation neutrino detectors are developed for the nextgeneration accelerator neutrino experiments. Such detectors will incorporate scintillation modules with scintillation counters that form X and Y planes. A single counter is a 7 × 10 × 90 mm3 scintillation bar with gluedin wavelength-shifting fibers and micropixel avalanche photodiodes. The results of measurements of the parameters of these detectors are presented.

The design of a photodetector unit of a new Shashlyk EM calorimeter for COMPASS II

A nine-channel photodetector unit with micropixel avalanche photodiodes (MAPD) and precision thermostabilization based on the compact Peltier module is designed and constructed. MAPD-3N with a high pixel density of 15,000 per square mm and area 3×3mm2 produced by Zecotek were used.

A new method to improve multiplication factor in micro-pixel avalanche photodiodes with high pixel density

Presented is a new model describing development of the avalanche process in time, taking into account the dynamics of electric field within the depleted region of the diode and the effect of parasitic capacitance shunting individual quenching micro-resistors on device parameters. Simulations show that the effective capacitance of a single pixel, which defines the multiplication factor, is the sum of the pixel capacitance and a parasitic capacitance shunting its quenching micro-resistor. Conclusions obtained as a result of modeling open possibilities of improving the pixel gain in micropixel avalanche photodiodes with high pixel density (or low pixel capacitance).

Study of a 3×3 module array of the ECAL0 calorimeter with an electron beam at the ELSA

ECAL0 is a new electromagnetic calorimeter designed for studying generalized parton distributions at the COMPASS II experiment at CERN. It will be located next to the target and will cover larger photon angles (up to 30 degrees). It is a modular high-granularity Shashlyk device with total number of individual channels of approx. 1700 and readout based on wavelength shifting fibers and micropixel avalanche photodiodes. Characterization of the calorimeter includes tests of particular sub-components, tests of complete modules and module arrays, as well as a pilot run of a fully-functional, quarter-size prototype in the COMPASS experiment. The main goals of the tests on low-intensity electron beam at the ELSA accelerator in Bonn were: to provide energy calibration using electrons, to measure angular response of the calorimeter and to perform an energy scan to cross-check previously collected data. A dedicated measurement setup was prepared for the tests, including a 3x3 array of the ECAL0 modules, a scintillating-fibre hodoscope and a remotely-controlled motorized movable platform. The measurements were performed using three electron energies: 3.2 GeV, 1.6 GeV and 0.8 GeV. They include a calibration of the whole detector array with a straight beam and multiple angular scans.