High Photon Detection Efficiency Research Articles

Silicon photomultipliers for future HEP experiments

For the particle identification systems of the future high-energy physics detectors, single-photon sensors with sub-mm granularity, high sensitivity, and mitigation strategy for operation in the neutron-irradiated areas are needed. Silicon photomultipliers are considered a baseline technology because of their high photon detection efficiency, good timing resolution, and low operating voltage compared to those of vacuum-based photo sensors. After neutron irradiation, the dark counts increase dramatically and distort the signal baseline, making the single photons indistinguishable. Although the DCR of different unirradiated SiPMs varies, the devices show very similar rates when irradiated to high doses. In this work, we investigated the performance parameters of FBK NUV-HD-RH UHD-DE 1 mm2 devices and determined the working temperature. We show that the maximum operation temperature for samples irradiated with a fluence of 1012 neq/cm2 is around -100°C.

A wide dynamic range front-end electronics for SiPMs using high-speed operational and integration amplifiers

Silicon photomultipliers (SiPM) have gained popularity in particle physics due to their inherent advantages in terms of compactness, low power consumption, and high photon detection efficiency. Moreover, we have to deal with signals ranging from a few photoelectrons (PE), where we need to reconstruct the exact shape, up to thousands of PEs in short time intervals.The design of this amplifier was conceived to handle the SiPMs signal in both cases, combining together a high-speed amplifier for precisely reconstruct the shape of the signals of a few PEs and an integrated one in which the output voltage level is directly proportional to the number of the input PEs.

Highly sensitive volumetric single-molecule imaging.

Volumetric subcellular imaging has long been essential for studying structures and dynamics in cells and tissues. However, due to limited imaging speed and depth of field, it has been challenging to perform live-cell imaging and single-particle tracking. Here we report a 2.5D fluorescence microscopy combined with highly inclined illumination beams, which significantly reduce not only the image acquisition time but also the out-of-focus background by ∼2-fold compared to epi-illumination. Instead of sequential z-scanning, our method projects a certain depth of volumetric information onto a 2D plane in a single shot using multi-layered glass for incoherent wavefront splitting, enabling high photon detection efficiency. We apply our method to multi-color immunofluorescence imaging and volumetric super-resolution imaging, covering ∼3-4 µm thickness of samples without z-scanning. Additionally, we demonstrate that our approach can substantially extend the observation time of single-particle tracking in living cells.

Reactor neutrino physics potentials of cryogenic pure-CsI crystal

AbstractThis paper presents a world-leading scintillation light yield among inorganic crystals measured from a 0.5 kg pure-CsI detector operated at 77 Kelvin. Scintillation photons were detected by two 2-inch Hamamatsu SiPM arrays equipped with cryogenic front-end electronics. Benefiting the light yield enhancement of pure-CsI at low temperatures and the high photon detection efficiency of SiPM, a light yield of 30.1 photoelectrons per keV energy deposit was obtained for X-rays and $$\gamma $$ γ -rays with energies from 5.9 to 59.6 keV. Instrumental and physical effects in the light yield measurement are carefully analyzed. This is the first stable cryogenic operation of kg-scale pure-CsI crystal readout by SiPM arrays at liquid nitrogen temperatures for several days. The world-leading light yield opens a door for the usage of pure-CsI crystal in several fields, particularly in detecting the coherent elastic neutrino-nucleus scattering of reactor neutrinos. The potential of using pure-CsI crystals in neutrino physics is discussed in the paper.

Measurement of the photon detection efficiency of Hamamatsu VUV4 SiPMS at cryogenic temperature

Liquid argon time projection chambers (TPC) are widely used in neutrino oscillation and dark matter experiments. Detection of scintillation light in liquid argon TPC’s is challenging because of its short wavelength, in the VUV range, and the cryogenic temperatures (∼86 K) at which the sensors must operate. Wavelength shifters (WLS) are typically needed to take advantage of the high Photon Detection Efficiency (PDE) in the visible range of most of photondetectors. The Hamamatsu VUV4 S13370–6075CN SiPMs can directly detect VUV light without the use of WLS, which main benefit is an improved PDE at these short wavelengths, but also the visible light from WLS. The manufacturer (Hamamatsu Photonics K.K.) provides a complete characterization of these devices at room temperature; however, previous studies have indicated a decrease of the PDE at cryogenic temperature for VUV light. In this work, we present the measurement of the PDE of VUV4 SiPMs at cryogenic temperature for different wavelengths in the range [270, 570] nm. A dedicated measurement at 127 nm is also shown.

Fabrication and characterization of silicon SPADs with doping compensated avalanche region

The features of avalanche region are of importance of SPAD. An ideal broad and rectangular avalanche field may reduce dark count rate but could hardly be realized by actual fabricating technology. We propose a new fabrication process including successive boron and phosphorus diffusions for building special doping compensated avalanche region. A low dark count rate below 10 cps at −20 °C and high photon detection efficiency about 70% at 850 nm are achieved. The afterpulsing probabilities are 2.3% at 20 °C and 3% at 0 °C. FWHM of time resolution is 340ps.

An efficient modeling workflow for high-performance nanowire single-photon avalanche detector

Single-photon detector (SPD), an essential building block of the quantum communication system, plays a fundamental role in developing next-generation quantum technologies. In this work, we propose an efficient modeling workflow of nanowire SPDs utilizing avalanche breakdown at reverse-biased conditions. The proposed workflow is explored to maximize computational efficiency and balance time-consuming drift-diffusion simulation with fast script-based post-processing. Without excessive computational effort, we could predict a suite of key device performance metrics, including breakdown voltage, dark/light avalanche built-up time, photon detection efficiency, dark count rate, and the deterministic part of timing jitter due to device structures. Implementing the proposed workflow onto a single InP nanowire and comparing it to the extensively studied planar devices and superconducting nanowire SPDs, we showed the great potential of nanowire avalanche SPD to outperform their planar counterparts and obtain as superior performance as superconducting nanowires, i.e. achieve a high photon detection efficiency of 70% with a dark count rate less than 20 Hz at non-cryogenic temperature. The proposed workflow is not limited to single-nanowire or nanowire-based device modeling and can be readily extended to more complicated two-/three dimensional structures.

Silicon photomultipliers for the SST camera of the Cherenkov Telescope Array

The Cherenkov Telescope Array Observatory (CTAO) will be the major global observatory for gamma-ray astronomy over the next decade and beyond. It will consist of two arrays of telescopes of different sizes, one for each hemisphere, and will be sensitive to gamma rays in the energy range from a few tens of GeV to hundreds of TeV. The Small-Sized Telescopes (SSTs) are a crucial component of the southern array, as they will extend the sensitivity of the observatory to the highest energies. Their focal plane will be equipped with 2048 Silicon Photomultiplier (SiPM) pixels, each one read independently by a state-of-the-art full waveform sampling readout. These solid-state sensors offer advantages over the traditional photomultiplier tubes, such as lower operating voltage, higher photon detection efficiency, and tolerance to bright illumination. In particular, they are the best choice for a small and compact camera such as the SST one. After a detailed comparative study, LVR3-type SiPMs from Hamamatsu Photonics were selected, with an active area of 6 mm × 6 mm, a microcell of 50 μm and without a protective coating, for optimum performance. The sensors demonstrated to have a higher photon detection efficiency and a lower crosstalk compared to the competitors, alongside a low dark count rate. In this contribution, we present the selection process and the latest measurements performed on the SiPMs mounted on the SST Camera module.

Design and simulation of a near-infrared enhanced Si-based SPAD for an automotive LiDAR.

A near-infrared (NIR)-enhanced single-photon avalanche diode (SPAD) with a retrograded NM/XP junction for an automotive LiDAR was designed based on CSMC 0.18µm BCD technology. A 3µm depth NM/XP junction embedded in a lightly doped deep p-well (DP) improves the absorption efficiency in the NIR regime; the photo-generated electrons generated in the depletion region are efficiently collected into the central multiplication region by a drift process, and then the impact ionization is triggered by the strong field, resulting in a high photon detection efficiency (PDE). Additionally, the deep NM/XP junction and the buried layer effectively isolate the dark noise originating from the interface and the substrate. The SPAD was initially simulated by numerical calculation, and then was evaluated with active quench/reset electronics in a circuit simulator. The results revealed that the SPAD with an active area of 314µm 2 achieves a PDE of 16.2% at 905nm and a dark count rate (DCR) of 1.46H z/µm 2, with an excess bias of 5V at room temperature. The designed SPAD is well suited for the low-cost, miniaturized automotive LiDAR.

Performance evaluation of the 8-inch MCP-PMT for Jinping Neutrino Experiment

Jinping Neutrino Experiment plans to deploy a new type of 8-inch MCP-PMT with high photon detection efficiency for MeV-scale neutrino measurements. This work studies the performance of the MCP-PMTs, including the photon detection efficiency, the charge resolution of the single photoelectron, the transition time spread, single photoelectron response, rates of dark counts and after pulses. We find a long tail in the charge distribution, and combined with the high photon detection efficiency, the overall energy resolution sees substantial improvements. Those results will be provided as the inputs to detector simulation and design. Our results show that the new PMT satisfies all the requirements of the Jinping Neutrino Experiment.

Time Coding-Based Single-Photon-Counting Lidar for Obtaining Spatial Location

This paper proposes a single-photon-counting lidar based on time coding that can obtain the target’s spatial location and measure the distance and azimuth angle in real time without needing a scanning device. Multiple optical fibers were used to introduce laser echo photons into a single-pixel single-photon detector. According to the deviation in the detection time of the echo photons passing through different optical fibers, multiple distances can be obtained simultaneously. Combining the measured distances with the fiber spacing allows the calculation of the distance, azimuth angle, and spatial coordinates of the target. This lidar has the advantages of high photon detection efficiency, short signal acquisition time, and low cost compared to array detectors.

High-performance waveguide coupled Germanium-on-silicon single-photon avalanche diode with independently controllable absorption and multiplication

Abstract Germanium-on-silicon (Ge-on-Si) single photon avalanche diodes (SPADs) have received wide attention in recent years due to their potential to be integrated with Si photonics. In this work, we propose and demonstrate a high-performance waveguide coupled Ge-on-Si separate-absorption-charge-multiplication SPAD with three electric terminals. By providing two separate voltage drops on the light absorption and multiplication regions, the drift and multiplication of carriers can be optimized separately. This indeed improves the freedom of voltage regulation for both areas. Moreover, thanks to the separate controlling, doping profile of the charge layer is greatly released compared to that of the conventional device because of the flexible carrier injection. In this scenario, the dark counts of the detector can be largely reduced through decreasing the electric field on the sidewalls of the Ge absorption region without affecting the detection efficiency. The proposed SPAD exhibits a high on-chip single photon detection efficiency of 34.62% and low dark count rates of 279 kHz at 1310 nm with the temperature of 78 K. The noise equivalent power is as low as 3.27 × 10−16 WHz−1/2, which is, to the best of our knowledge, the lowest of that of the reported waveguide coupled Ge-on-Si SPADs. This three-terminal SPAD enables high-yield fabrication and provides robust performance in operation, showing a wide application prospect in applications such as on-chip quantum communication and lidar.

Hybrid and heterogeneous photonic integrated near-infrared InGaAs/InAlAs single-photon avalanche diode

We have demonstrated the integrated indium gallium arsenide/indium aluminum arsenide (InGaAs/InAlAs) single-photon avalanche diodes (SPAD) with silicon (Si) waveguides and grating couplers on the Silicon-on-insulator substrate. A vertical coupling scheme is adopted which allows the use of a thick bonding interlayer for high yield. The epoxy ‘SU-8’ is selected to be the adhesion layer with a low transmission loss, low volumetric shrinkage, and low curing temperature. In addition, both hybrid and heterogeneous integration schemes are realized which are compatible with the current multi-project wafer process. Extensive performance characterization is carried out while the results are compared. Our hybrid integrated SPAD exhibits high photon detection efficiency (PDE) of ∼21% and a relatively low dark count rate (DCR) of 8.6 × 105 Hz, which are among the best performance reported for InGaAs/InAlAs SPADs while the heterogeneous integrated SPAD shows a decent PDE of 6% with a DCR of 2 × 107 Hz. Combined with the inherent wide applicability of the bonding using the SU-8 layer, this photonic integration provides a promising solution for large-scale quantum information with various material systems.

Design and Characterization of n/p-well CMOS SPAD With Low Dark Count Rate and High Photon Detection Efficiency

We have proposed a structure design of single-photon avalanche diode fabricated in the Taiwan Semiconductor Manufacturing Company Ltd. (TSMC) 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> high-voltage (HV) CMOS technology, which improves the limited operating excess voltage for an n-on-p design without any other customized well layer. With the introduction of a deep p-well isolation (ISO) layer, the excess bias is significantly elevated, so that the device exhibits high photon detection probability (PDP) with relatively low dark count rate. The n-on-p-type device is favorable for 3-D-stacked backside illuminated structure and can attain high PDP at longer wavelength. With the improved jitter and after-pulsing probability, our designed device can be suitable for the application of light detection and ranging (LiDAR).

High-sensitivity low-noise photodetector using a large-area silicon photomultiplier.

The application of silicon photomultiplier (SiPM) technology for weak-light detection at a single photon level has expanded thanks to its better photon detection efficiency in comparison to a conventional photomultiplier tube (PMT). SiPMs with large detection area have recently become commercially available, enabling applications where the photon flux is low both temporarily and spatially. On the other hand, several drawbacks exist in the usage of SiPMs such as a higher dark count rate, many readout channels, slow response time, and optical crosstalk; therefore, users need to carefully consider the trade-offs. This work presents a SiPM-embedded compact large-area photon detection module. Various techniques are adopted to overcome the disadvantages of SiPMs so that it can be generally utilized as an upgrade from a PMT. A simple cooling component and recently developed optical crosstalk suppression method are adopted to reduce the noise which is more serious for larger-area SiPMs. A dedicated readout circuit increases the response frequency and reduces the number of readout channels. We favorably compare this design with a conventional PMT and obtain both higher photon detection efficiency and larger-area acceptance.

High-Density Near-Ultraviolet Silicon Photomultipliers: Characterization of photosensors for Cherenkov light detection

In recent years, Silicon Photomultipliers (SiPMs) have proven to be highly suitable devices for applications where high sensitivity to low-intensity light and fast responses are required. Among their many advantages are their low operational voltage when compared with classical photomultiplier tubes, mechanical robustness, and increased photon detection efficiency (PDE).Here we present a full characterization of a SiPM device technology developed in Italy by Fondazione Bruno Kessler, which is suitable for Cherenkov light detection in the Near-Ultraviolet (NUV) band. This device is a High-Density (HD) NUV SiPM, based on a microcell of 40μm×40μm and with an area of 6 × 6mm2, providing low levels of dark noise and high PDE peaking in the NUV band. This particular device has been selected to equip a part of the focal plane of the Schwarzschild–Couder Telescope (SCT) prototype proposed for the Cherenkov Telescope Array (CTA) Observatory.

Parametrization of high light yield, energy resolution, and optical cross-talk in SiPM-based liquid argon detectors

Liquefied noble gases are widely used as detector media in various physics experiments owing to their high scintillation efficiency and ease of scalability to large volumes. Now-a-days, these experiments are gradually shifting to SiPM-based readouts because of their high photon detection efficiency, superior resolution, and relative ease of use. However, SiPMs emit photons during the avalanche process, known as optical cross-talk, which can significantly affect the measured signal. In this work, we present two small single-phase liquid argon chambers equipped with SiPM arrays. They display high gross light yields up to 32 photo-electrons per keV, with ∼12 attributed to primary photo-electrons generated by scintillation photons. We then present the full parametrization of the over-voltage dependence of the light yield, energy resolution, and optical cross-talk, based on dedicated measurements of optical cross-talk components and a simple analytical model.

Tip Avalanche Photodiode—A spherical-junction SiPM concept

An avalanche region of APD cells in modern SiPMs is formed by a planar p–n junction, where an edge breakdown is suppressed by area-consuming measures. Performance of the planar SiPMs is limited by an inherent trade-off between photon detection efficiency (PDE) affected by an inactive cell area and dynamic range dependent on the cell pitch and capacitance. To overcome the limitations of the planar SiPM design, a spherical-junction-based SiPM – Tip Avalanche Photodiode (TAPD) – has recently been developed. Its quasi-spherical tips turn the edge breakdown problem into benefits of highly efficient collection and multiplication of photoelectrons in focusing electric field, low breakdown voltage, low cell capacitance, and eliminate needs in the separation borders between the APD cells. TAPD samples of 15 um pitch outperform the state-of-the-art SiPMs in the record PDE of 73% at the peak sensitivity wavelength of 608 nm. Moreover, the PDE is above 45% in a range of 400 to 800 nm and 22% at 905 nm. The high PDE is accompanied by the fast single electron response and cell recovery time of about 4 ns due to the low capacitance of the tips. The report presents an overview of the spherical-junction-based APD and SiPM designs and features.

High photon detection efficiency InGaAs/InP single photon avalanche diode at 250 K

Planar semiconductor InGaAs/InP single photon avalanche diodes with high responsivity and low dark count rate are preferred single photon detectors in near-infrared communication. However, even with well-designed structures and well-controlled operational conditions, the performance of InGaAs/InP SPADs is limited by the inherent characteristics of avalanche process and the growth quality of InGaAs/InP materials. It is difficult to ensure high detection efficiency while the dark count rate is controlled within a certain range at present. In this paper, we fabricated a device with a thick InGaAs absorption region and an anti-reflection layer. The quantum efficiency of this device reaches 83.2%. We characterized the single-photon performance of the device by a quenching circuit consisting of parallel-balanced InGaAs/InP single photon detectors and single-period sinusoidal pulse gating. The spike pulse caused by the capacitance effect of the device is eliminated by using the characteristics of parallel balanced common mode signal elimination, and the detection of small avalanche pulse amplitude signal is realized. The maximum detection efficiency is 55.4% with a dark count rate of 43.8 kHz and a noise equivalent power of 6.96 × 10−17 W/Hz1/2 at 247 K. Compared with other reported detectors, this SPAD exhibits higher SPDE and lower noise-equivalent power at a higher cooling temperature.

Study on the Optimized Energy Resolution of Scintillator Detectors Based on SiPMs and LYSO:Ce

The cerium-doped lutetium yttrium silicate (LYSO:Ce) crystal has many advantages such as high light output and fast decay time, showing great potential to improve the performance of scintillation detectors. Silicon photomultipliers (SiPMs) are high-performance semiconductor photodetectors, which generally have a higher photon detection efficiency than photomultiplier tubes (PMTs) and are beneficial to realize a better energy resolution. The energy resolution and detected light output of SiPM-coupled LYSO:Ce crystals were studied by optimizing the photon detection efficiency (PDE), the operating voltage, the wrapper, the surface finish and the coupling method between the SiPM and crystal. Considering the output saturation of SiPMs in high light intensity, a preliminary correction method was applied to the saturation response of SiPMs and energy resolution of 662 keV gamma-rays from 137Cs was obtained after correction. The results show that the optimized energy resolution at 662 keV measured by the SiPM of 50 μm microcells can reach 7.6%. The light output of the polished and rough crystal detected by a SiPM of 10 μm microcells were also measured, which can reach 27000 ± 3200 photons/MeV and 36000 ± 3700 photons/MeV, respectively.