Detector Readout Research Articles

Tuning of nuclear spectroscopic telescope array application specific integrated circuits to improve low energy threshold of future hard x-ray imaging detectors

Detector commanding, processing and readout of spaceborne instrumentation is often accomplished with application specific integrated circuits (ASICs). The ASIC designed for the nuclear spectroscopic telescope array (NuSTAR) mission enables future tiled CdZnTe (CZT) detector array readout for x-ray detectors, such as the high resolution energetic x-ray imager (HREXI). Modified NuSTAR ASIC (NuASIC) gain settings have been implemented for HREXI’s broader targeted imaging energy range (3 to 300 keV) compared with NuSTAR (2 to 79 keV), which may require updated NuASIC internal parameters for optimal energy resolution. To reach HREXI’s targeted low energy threshold, we have also enabled the NuASIC’s “charge pump mode,” which introduces an additional tuning parameter. We describe the mechanics of the NuASIC’s adjustable parameters and use our recently developed ASIC test stand to probe a “bare” NuASIC using its internal test pulser. We record the effects of parameter tuning on the device’s electronics noise and low energy threshold and report the optimal set of parameters for HREXI’s updated gain setting. We detail a semiautomated procedure to derive the optimal parameters for each of HREXI’s large area closely tiled NuASIC/CZT detectors to expedite instrument integration.

The Solar Ultraviolet Imaging Telescope: detector characterization and readout electronics testing

ABSTRACT The Solar Ultraviolet Imaging Telescope (SUIT) is one of the payloads onboard the Aditya-L1 mission. It will perform full disc imaging of the Sun in the near-ultraviolet (UV) wavelength range of 200–400 nm. This provides near-simultaneous observations of the Sun from the photosphere and chromosphere. A back-illuminated, enhanced UV charge coupled device (CCD) of size 4096 (H) × 4136 (V) pixels, with a pixel size of 12 μm, is used as an imaging element in SUIT. The CCD characterization and the readout electronics development and testing were performed in-house at the Space Astronomy Group, U R Rao Satellite Centre, ISRO. The test set-up and procedures are explained and the measured values of various parameters including noise, dark current, gain, linearity, and cross-talk are presented in this paper. The results show a satisfactory performance from the CCD as well as the readout electronics to meet the specifications required by the SUIT payload.

BETSEE: testing for system-wide effects of single event effects on ITk strip modules

The Inner Tracker silicon strip detector (ITk Strip) is a part of the ATLAS upgrade for the HL-LHC. The detector readout and control is accomplished by the interaction of three on-module custom ASICs (ABCStarv1, HCCStarv1 and AMACstar). All ASICs are designed with protections against Single Event Errors. Their resilience at the system-level can be tested using the Board for Evaluation of Triple-chip Single Event Effects (BETSEE). This special board places all three ASICs into the beam-spot of a test beam facility concurrently and allows for module-like operation. The results from irradiating BETSEE with heavy ions and protons will be presented.

Construction and test of a transition-radiation detector prototype based on thick gas electron multiplier technology

A transition-radiation detector (TRD) is a powerful device for highly relativistic electron (γ ≳ 1,000) identification. Electron identification is crucial for tagging the outgoing scattered electrons in an electron-ion collider (EIC) detector. Employing a TRD at the electron forward region of an EIC detector can provide the necessary electron identification with high hadron rejection over a wide momentum range. Thick gas electron multiplier (THGEM) technology is suitable for radiation detection in modern high-energy experiments owing to its high-granularity structure, radiation hardness, high-rate capability and ease of large-area production. This study investigates a TRD prototype based on THGEM technology through soft X-ray and electron beam experiments. Geant4 simulation were extensively exploited to understand the operation of TRD prototype with different gas mixtures. Particularly, the performance of TRD prototype with an electron beam at the DESY, with argon-based gas rather than xenon-based gas, agreed well with the simulation analyses in all important aspects. Based on the consistency of the experimental and simulation results, a likelihood analysis on the simulated total energy deposit in the xenon-based working gas would suggest a pion rejection improvement with the optimization of detector design, readout electronics and identification algorithm.

Degradation of signal-to-noise ratio in counting detectors due to pile-up effects

This work proposes a methodology to quantify how the non-linearity of counting detectors due to pulse pile-up effects impacts detrimentally the signal-to-noise ratio of measurements and the resulting DQE. The method is presented from a conceptual point of view, justified and validated by both analytical and Monte Carlo methods applied to the ideal theoretical pile-up models usually discussed in the literature. Although the motivation of this work is the application to photon counting X-ray detectors, the study may be relevant for other type of particle or radiation detection systems operating at high count rate regimes, when pile-up is not negligible. The high count rates can be managed in actual experiments by implementing pile-up compensation methods in the detector readout chain, by applying correction algorithms to the measured data or by a combination of both. What has been less discussed in literature is the impact of those pile-up compensation techniques on the final statistical properties of the resulting data, and the proposed method can be potentially used for that purpose. The application of the method to more realistic systems is illustrated with an example of a simulated 2D X-ray photon counting detector that includes all the primary physical effects and the full readout chain.

Upgrade to the focal-plane detector system of the S800 spectrograph at FRIB

The present work describes the ongoing upgrade of the focal-plane detector system and the associated data acquisition system of the large-acceptance S800 magnetic spectrograph. It includes the development of an innovative micro-pattern gaseous detector readout for the tracking system, a novel energy-loss detector concept for Z-identification, and a high resolution optical readout for the timing scintillator detector. The upgraded focal-plane detector system will allow for improved particle identification for heavy-ion beams above Z=100, at higher rate capability (> 25 kHz).

BINGO: Background reduction techniques for 0ν2β bolometric experiments

BINGO is a project dedicated to explore new methods for background reduction in experiments searching for 0ν2β decay. It is based on bolometers, one of the most promising techniques to search for 0ν2β. CUORE and CUPID-Mo/0 are the main bolometric experiments that have illustrated the most relevant limiting factors on sensitivity the bolometers are facing. Surface αs are the main source of background in CUORE, and this contribution has been mitigated in CUPID-Mo/0 using dual heat-light channels, i.e., a main absorber embedding the 2β decay isotope facing a light detector. In this case, surface α rejection is achieved thanks to the lower α light output compared to β/γ. However, there are still other background components that limit the sensitivity of the experiments, such as pile-ups due to random coincidences of physical events, external γ background and β surface radioactivity. BINGO’s proposed technology aims at reducing the background index down to 10−5 counts/(keV kg yr) in the region of interest, thus boosting the sensitivity on the effective Majorana neutrino mass. This can be achieved by: (i) having a revolutionary detector assembly with a reduction in the passive materials facing the detector; (ii) increasing the light detector sensitivity thanks to Neganov-Luke amplification; (iii) using an active shield, based on BGO scintillators with bolometric light detector readout to surround the experimental volume. The main text describes the listed approaches in detail, as well as the recent results of prototype tests.

Response of a Liquid 3He Neutron Detector

The 3He(n,p) process is excellent for neutron detection between thermal and ∼4 MeV because of the high cross section and near-complete energy transfer from the neutron to the proton. This process is typically used in gaseous forms with ionization readout detectors. Here we study the response of a liquid 3He neutron detector with a scintillation readout. We anticipate an efficiency boost of around a factor of 64 compared to 10-atm gaseous detectors, given similar detector volumes.

FELIX: Readout upgrade for the ATLAS Trigger DAQ system in HL-LHC

The High Luminosity LHC (HL-LHC) will start to operate in 2029 (Run 4) with an instantaneous luminosity five times higher than the LHC nominal value, meaning the ATLAS experiment will be operated in an increasingly harsh collision environment. This has motivated a series of upgrades, to be installed during the long experimental shutdown period from 2026 to 2029. One key change among these is the upgrade of the Front-End Link eXchange (FELIX) system, which was developed for the third major LHC data taking period (Run 3) from 2022 to 2025 to improve the capacity and the flexibility of the detector readout system for selected ATLAS systems. After the HL-LHC upgrade, all ATLAS systems will be read out via the FELIX system, with sub-detector specific processing taking place in a common software processing framework.

KITE: High frame rate, high count rate pixelated electron counting ASIC for 4D STEM applications featuring high-Z sensor

KITE is a novel mixed-mode CMOS electron counting ASIC developed for the readout of pixelated semiconductor radiation detectors targeted to 4D STEM applications. The chip features a pixel pitch of 100 μm arranged in a 192 × 192 matrix and can be bump-bonded to both Si and high-Z sensor materials. The design of an extremely fast front-end electronics and the use of the instant retrigger mechanism allow for a non-paralyzable counting mode up to above 108 cts/s/pix, which corresponds to a 300 keV electron beam current of 14 pA/pix. The massive parallel readout in combination with two on-chip data compression techniques – 2 × 2 pixel digital binning and floating-point counter encoding – allows for frame rates higher than 100 kfps (this work), in principle extendable to almost 500 kfps with improved readout boards. We successfully characterized a first detector prototype featuring a 1500 μm-thick CdZnTe sensor with fluorescence X-rays from elemental targets and with 200 keV and 300 keV electrons in terms of energy response, threshold trimming accuracy, single event multiplicity distribution, spatial uniformity and temporal stability, count rate capability and imaging performances (MTF and DQE). Custom Monte Carlo simulations complemented when possible the experimental data for cross-validation purposes, generally with a very good matching. Finally, a proof-of-concept 4D STEM acquisition is presented and discussed.

Neutron and beta imaging with Micromegas detectors with optical readout

Recent developments have shown that coupling a Micromegas gaseous detector on a glass substrate with a transparent anode and a CMOS camera enables the optical readout of Micromegas detectors with a good spatial resolution, demonstrating that the glass Micromegas detector is well-suited for imaging. This feasibility test has been effectuated with low-energy X-ray photons also permitting energy resolved imaging. This test opens the way to different applications. Here we will focus on two applications. Namely, neutron imaging for non-destructive examination of highly gamma-ray emitting objects, such as irradiated nuclear fuel or radioactive waste. And secondly, we are developing a beta imager for the cell tagging in the field of anticancerous drug studies.Both applications require to design the detectors in view of the specific constraints of reactor dismantling and medical applications: spatial resolution and strong gamma suppression for neutron imaging and precise rate and energy spectrum measurements for the beta.A dedicated system consisting of a glass Micromegas detector and an ultrasensitive camera has been designed and assembled. Here we present the first results from the characterization of the detectors, as well as the first acquired images.

ATLAS ITk tracking and readout performance

The ATLAS Inner Detector will be replaced with a new all-silicon Inner Tracker (ITk) designed for the challenging environment of the High Luminosity LHC (HL-LHC). The ITk layout of the pixel detector was recently successfully optimized to improve tracking performance and object reconstruction. The data rates of the ITk pixel detector have been evaluated to establish that the detector readout system can read out data at the design L0 trigger frequency of 1 MHz.

A Superconducting RF Low-Pass Filter Based on Ti/TiN Artificial Transmission Line for Detector and Qubit Readout

A Superconducting RF Low-Pass Filter Based on Ti/TiN Artificial Transmission Line for Detector and Qubit Readout

A new data transfer scheme for the HL-LHC upgrade of the ATLAS Tile Hadronic Calorimeter

The Large Hadron Collider (LHC) is undergoing a series of upgrades towards a High Luminosity LHC (HL-LHC) that will deliver five times the LHC nominal instantaneous luminosity. The ATLAS experiment is one of the experiments at the LHC that investigates elementary particle interactions in collisions of high-energy proton beams. To prepare for data taking in high-luminosity conditions, the ATLAS Tile Hadronic Calorimeter (TileCal) will replace completely on- and off-detector electronics using a new read-out architecture. The TileCal detector signals will be digitized by on-detector electronics and transferred to the TileCal PreProcessors (TilePPr), which comprise the main component of the off-detector electronics. In the TilePPr, the digitized data will be stored in pipeline buffers and be packed and read out to the Front-End LInk eXchange (FELIX) system upon the reception of a trigger decision. FELIX is a new detector readout component being developed as part of the ATLAS upgrade effort. FELIX is designed to act as a data router between the data acquisition detector control and TTC (Timing, Trigger and Control) systems and the new or updated trigger and detector front-end electronics. Whereas previous detector readout implementations relied on diverse custom hardware platforms, the idea behind FELIX is to unify all readout across one well supported and flexible platform.

Double-hit separation and dE/dx resolution of a time projection chamber with GEM readout

A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at the planned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC was placed in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earlier tests. New studies are presented with first results on the separation of close-by tracks and the capability of the system to measure the specific energy loss dE/dx. This is complemented by a simulation study on the optimization of the readout granularity to improve particle identification by dE/dx.

TPC development by the LCTPC collaboration for the ILD detector at ILC

The International Large Detector (ILD) at the International Linear Collider (ILC) requires significantly improved subdetector systems to comply with the envisioned performance. Its central tracking detector is a Time Projection Chamber (TPC) which is equipped with Micropattern Gaseous Detector (MPGD) readout modules. The LCTPC collaboration was founded in 2007 to design such a MPGD-based TPC and to build and test demonstrator modules. For this an experimental setup at DESY, Hamburg, was built, where four different readout concepts have been studied in many successful test beam campaigns since 2010. It could be demonstrated that the required transverse and longitudinal space point resolutions can be reached. Also, a new gating concept was developed that can effectively eliminate the ion backflow, while marginally degrading the performance of the detector.

Development of a Segmented GEM Readout detector

Micromegas (Micro-MEsh GAseous Structures) detectors are a type of micro-pattern gaseous detectors. The primary charges are amplified in electron avalanches between a planar anode and a mesh typically 120 μm above the anode. For resistive anode type Micromegas detectors the signal is read out via copper readout strip layers below the anode. A 2D particle position can be reconstructed using two perpendicular readout strip layers below the resistive anode structure.Using a standard 2D resistive anode Micromegas readout structure, a unique 2D particle position reconstruction is only possible if the detector is hit by only one particle at the same time. Ambiguities will occur if multiple particles arrive at the same time. A unique X–Y assignment is strongly complicated.This issue can be resolved by replacing the mesh with a GEM (Gas Electron Multiplier) foil, which is segmented into 0.5 mm wide strips on at least one of the two sides. The GEM strips need to be turned by 45∘ with respect to the Micromegas readout strips. Thus the detector with a GEM foil segmented on both sides has four readout strip directions (X, Y, U and V) and a detector with a GEM foil segmented on only one side has three readout strip directions (X, Y and V).A prototype of such a Segmented GEM Readout (SGR) detector is built with GEM strips and readout strips perpendicular to each other. Test beam measurements with this detector were performed using 120 GeV muons. Results of the test beam measurements are presented here.

Data pre-processing with high-level-synthesis and dataflow programming using HLS C++ dataflow template library

The readout of detectors with FPGAs is a common practice. Traditionally, this is done using a hardware description language such as VHDL, Verilog, or System Verilog. Data is preprocessed, filtered, and passed to high-performance computing clusters for the next processing steps. Many experiments require a continuous, trigger-less data stream, which significantly increases the algorithmic requirements. In this work, we show how to implement the increasingly complex algorithms using methods of dataflow programming and methods of Modern HLS C++ Template Programming. The focus is also on resource consumption, which must remain below an acceptable limit compared to a pure VHDL implementation. Additional design goals are fast and shorter development time, easy maintenance, the ability to adapt algorithms to changing needs, and high throughput to handle continuous data streams. We present the concept of a dataflow template library that can be used to realize the above design goals. The template library allows an algorithm to be represented as a data flow graph. It is designed in such a way that the maximum possible data throughput can be implemented with an initiation interval of 1. The locality of the algorithm is instantiated by local streaming buffers. It is shown how these buffers are implemented in such a way that a nearly balanced graph is obtained.

A mixed-signal processor for X-ray spectrometry and tracking in the GAPS experiment

This paper reports the design and experimental results from the characterization of an integrated circuit developed for the readout of the X-ray spectrometer and tracking system of the General AntiParticle Spectrometer (GAPS) balloon mission. GAPS will search for an indirect signature of dark matter through the detection of low-energy (<0.25 GeV/n) cosmic-ray antiprotons, antideuterons and antihelium nuclei. The ASIC, named SLIDER32 (32 channels Si-LI DEtector Readout ASIC), was fabricated in a 180 nm CMOS technology and is comprised of 32 analog readout channels, an 11-bit SAR ADC and a digital back-end section which is responsible for defining channel settings and for sending digital information to the data acquisition system. The core of the ASIC is a low-noise analog channel implementing a dynamic signal compression which makes the chip suitable for resolving both X-rays in the range of 20 to 100 keV and charged particles with energy deposition of up to 100 MeV. It features an energy resolution of 4 keV FWHM in the 20–100 keV range with a 40 pF detector capacitance, to clearly distinguish X-rays from antiprotonic or antideuteronic exotic atoms. The readout electronics of the ASIC will run at a temperature of about –40 °C, complying with a detector leakage current of the order of 5–10 nA per strip.

Low power implementation of high frequency SiPM readout for Cherenkov and scintillation detectors in TOF-PET

State-of-the-art (SoA) electronic readout for silicon photomultiplier (SiPM)-based scintillation detectors that demonstrate experimental limits in achievable coincidence time resolution (CTR) leverage low noise, high frequency signal processing to facilitate a single photon time response that is near the limit of the SiPMs architecture. This readout strategy can optimally exploit fast luminescence and prompt photon populations, and promising measurements show detector concepts employing this readout can greatly advance PET detector CTR, relative to SoA in clinical systems. However, the technique employs power hungry components which make the electronics chain impractical for channel-dense time-of-flight (TOF)-PET detectors. We have developed and tested a low noise and high frequency readout circuit which is performant at low power and consists of discrete elements with small footprints, making it feasible for integration into TOF-PET detector prototypes. A 3 × 3 mm2 Broadcom SiPM with this readout chain exhibited sub-100 ps single photon time resolution at 10 mW of power consumption, with a relatively minor performance degradation to 120 ± 2 ps FWHM at 5 mW. CTR measurements with 3 × 3 × 20 mm3 LYSO and fast LGSO scintillators demonstrated 127 ± 3 ps and 113 ± 2 ps FWHM at optimal power operation and 133 ± 2 ps and 121 ± 3 ps CTR at 5 mW. BGO crystals 3 × 3 × 20 mm3 in size show 271 ± 5 ps FWHM CTR (1174 ± 14 ps full-width-at-tenth-maximum (FWTM)) at optimal power dissipation and 289 ± 8 ps (1296 ± 33 ps FWTM) at 5 mW. The compact and low power readout topology that achieves this performance thereby offers a platform to greatly advance PET system CTR and also opportunities to provide high performance TOF-PET at reduced material cost.