Fast Readout Speed Research Articles

Characterisation studies of two front-end electronics chips designed for SiPM readout

A new front-end ASIC named ”PIST” (pico-second timing) has been successfully developed using 55 nm CMOS technology for the silicon photomulplier (SiPM) readout with a single channel with a major aim of fast timing. We performed extensive tests to evaluate the timing performance of a dedicated test stand equipped with a PIST chip. The results show that the system timing resolution can reach sub 10 ps for large SiPM signals, while the PIST intrinsic timing resolution is better than 5 ps. The PIST dynamic range has been further extended using the time-over-threshold (ToT) technique. Meanwhile, we fully characterised a new commercially available SiPM-readout 32-channel ASIC for developments of future high-granularity crystal calorimetry, including the single photon calibration and the dynamic range of different gain regions. Other promising potentials include fast timing resolution, fast readout speed and low power dissipation. Comprehensive measurements were made with a laser beam and high-energy particle beams with crystals and SiPMs. First testing results show that this chip has an excellent signal-to-noise and a large dynamic range. This contribution will introduce the ASICs as well as dedicated test stands and also present highlighted results including the timing resolution, single photon calibration and dynamic range.

Readout circuit for a ZnO bulk-acoustic-wave X-ray dose rate detector

Bulk Acoustic Wave (BAW) resonators based on piezoelectric semiconductors are radio frequency devices that can convert X-ray dose rate into resonant frequency offset, which exhibit strong anti-interference capabilities and low power consumption and are suitable for wireless sensing systems. In this study, we designed a readout circuit for a ZnO BAW X-ray dose rate detector. (0001)-oriented ZnO single crystals were used to fabricate the high-quality BAW X-ray detector. Under dark field and X-ray irradiation conditions, the resonant frequency offset of the detector was recorded via the readout circuit. The readout circuit consists of an oscillator circuit based on a Pierce oscillator circuit structure, a frequency mixing circuit, and an STM32 microcontroller. This design offers higher frequency stability and lower phase noise. In practical applications, it can replace the expensive and bulky vector network analyzer for detecting and storing the resonant frequency of BAW resonators with the advantages of fast readout speed and portability.

Single-photon counting detectors for diffraction-limited light sources

When first introduced, single-photon counting detectors reshaped crystallography at synchrotrons. Their fast readout speed enabled, for example, shutter-less data collection and fine slicing of the rotation angle and boosted the development of new experimental techniques like ptychography. Under optimal conditions, single-photon counting detectors provide an unlimited dynamic range with image noise only limited by the Poisson statistics of the incoming photons. Counting the pulses from individual photons, essentially what made the detectors so successful, also causes the main drawback, which is the loss of efficiency at high photon fluxes due to pulse pileup in the analog front end. To fully take advantage of diffraction-limited light sources, the next-generation single-photon counters need to improve their count rate capabilities in the same order of magnitude as the increased flux. Moreover, fast frame rates (a few kHz) are required to cope with the shorter dwell time achievable, thanks to the higher flux. Detector architecture with multiple comparators and counters can open new possibilities for energy-resolved imaging, while interpixel communication can overcome the issues arising from charge sharing and reduce the loss of efficiency at the pixel corners. Coupling single-photon counting detectors to high-Z sensors for hard X-ray detection (>20 keV) and to low-gain avalanche diodes (LGADs) for soft X-rays is also necessary to make use of the increased coherence of the new light sources over the full radiation spectrum. In this paper, we present possible strategies to improve the performance of single-photon counting detectors at the fourth-generation synchrotron sources and compare them to charge integrating detectors.

Acoustic Ejection Mass Spectrometry: Fundamentals and Applications in High-Throughput Drug Discovery

ABSTRACT Introduction Acoustic ejection mass spectrometry (AEMS) is an electrospray ionization-mass spectrometry (ESI-MS) based analytical platform that provides high analytical throughput and data quality. It has been applied in numerous drug discovery workflows, such as high-throughput screening (HTS), absorption, distribution, metabolism, and excretion (ADME) profiling, pharmacokinetics (PK) analysis, compound quality control (QC), and the high throughput readout of medical chemistry samples. Areas covered This paper introduces the working principle of AEMS technology. The analytical performance, system tuning and method development workflows, and representative applications on high-throughput drug discovery assays are introduced. Expert opinion The fast sample readout speed, high reproducibility, wide compound coverage, minimum carryover, and the tolerance to complex sample matrices of AEMS have demonstrated its advantages over other technologies in this field, with broad applicability to a diverse range of drug discovery workflows. However, the current platform still has challenges for some assays due to having less sensitivity compared with liquid chromatography-mass spectrometry (LC-MS), and the lack of chromatographic separation for isomeric interferences. Despite the remaining hurdles, AEMS is becoming an attractive high-throughput analytical platform in drug discovery. Additional system developments would enable its further adoption in the future.

A Sub-GHz Impedance-Engineered Parametric Amplifier for the Readout of Sensors and Quantum Dots

In the work on superconducting parametric amplifiers, the frequency band below one gigahertz is calling for systematic improvements. Despite a prospect for ultralow added noise, bandwidth limitations have slowed down the integration of such amplifiers into sub-GHz experiments demanding fast ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; 1\, \mu$</tex-math></inline-formula> s) readout speeds. Here, we study the impedance engineering of a flux-driven Josephson parametric amplifier (JPA) at 600 MHz. We propose, simulate and experimentally demonstrate a partially reconfigurable impedance transformer. The transformer enhances the JPA bandwidth to a state-of-the-art value of 10 MHz at 20 dB gain. Our amplifier has immediate applications in the readout of cryogenic sensors and in the reflectometry of quantum dots for spin qubit quantum computing.

First results on SiSeRO devices: a new x-ray detector for scientific instrumentation

We present an evaluation of an on-chip charge detector, called the single electron sensitive read out (SiSeRO), for charge-coupled device image sensor applications. It uses a p-channel metal-oxide-semiconductor field-effect transistor (p-MOSFET) transistor at the output stage with a depleted internal gate beneath the p-MOSFET. Charge transferred to the internal gate modulates the source-drain current of the transistor. We have developed a drain current readout module to characterize the detector. The prototype sensor achieves a charge/current conversion gain of 700 pA per electron, an equivalent noise charge (ENC) of 15 electrons (e − ) root mean square, and a full width half maximum of 230 eV at 5.9 keV. Further, we discuss the SiSeRO working principle, the readout module developed at Stanford, and the first characterization test results of the SiSeRO prototypes. While at present only a proof-of-concept experiment, in the near future we plan to use next generation sensors with improved noise performance and an enhanced readout module. In particular, we are developing a readout module enabling repetitive non-destructive readout of the charge, which can in principle yield subelectron ENC performance. With these developments, we eventually plan to build a matrix of SiSeRO amplifiers to develop an active pixel sensor with an on-chip application specific integrated circuit-based readout system. Such a system, with fast readout speeds and subelectron noise, could be effectively utilized in scientific applications requiring fast and low-noise spectro-imagers.

2.45 e-RMS Low-Random-Noise, 598.5 mW Low-Power, and 1.2 kfps High-Speed 2-Mp Global Shutter CMOS Image Sensor With Pixel-Level ADC and Memory

This article presents a low random noise, a low-power, and a high-speed 2-mega pixels (Mp) global-shutter (GS)-type CMOS image sensor (CIS) using an advanced dynamic random access memory (DRAM) technology. GS CIS is one of the alternatives to solve image distortion issues caused by a conventional rolling-shutter (RS) CIS operation, since a 2-D image data can be simultaneously sampled by the in-pixel analog memory. To achieve a high-performance GS CIS, we proposed a novel architecture for digital pixel sensor (DPS) which is a high-speed GS operation CIS with a pixel-wise analog-to-digital converter (ADC) and an in-pixel digital memory. The major technologies of the proposed DPS can be summarized as follows: 1) two large coupling capacitors with mature DRAM technology; 2) extremely narrow pitch Cu-to-Cu (C2C) bond; and 3) finally low-powered ADC with a near sub-threshold operation. A perfect auto-zero operation for ADC is implemented using two DRAM capacitors, and a large number of transistors have to be integrated in the single pixel for realizing pixel-level ADC. Thus, each pixel has two fine-pitch C2C interconnections. This makes it possible to realize wafer-level stacked unit pixel. The proposed DPS with low-power consuming analog circuits has been successfully designed and developed for extremely fast-readout speed of max. 1200 frames per second (fps) and high sensitivity for low-illumination conditions.

Characterization and performance evaluation of the XSPA-500k detector using synchrotron radiation.

Hybrid photon counting (HPC) detectors are widely used at both synchrotron facilities and in-house laboratories. The features of HPC detectors, such as no readout noise, high dynamic range, high frame rate, excellent point spread function, no blurring etc. along with fast data acquisition, provide a high-performance detector with a low detection limit and high sensitivity. Several HPC detector systems have been developed around the world. A number of them are commercially available and used in academia and industry. One of theimportant features of an HPC detector is a fast readout speed. Most HPC detectors can easily achieve over 1000 frames s-1, one or two orders of magnitude faster than conventional CCD detectors. Nevertheless, advanced scientific challenges require ever faster detectors in order to study dynamical phenomena in matter. The XSPA-500k detector can achieve 56 kframes s-1 continuously, without dead-time between frames. Using `burst mode', a special mode of the UFXC32k ASIC, the frame rate reaches 1 000 000 frames s-1. XSPA-500k was fully evaluated at the Metrology beamline at Synchrotron SOLEIL (France) and its readout speed was confirmed by tracking the synchrotron bunch time structure. The uniformity of response, modulation transfer function, linearity, energy resolution and other performance metrics were also verified either with fluorescence X-rays illuminating the full area of the detector or with the direct beam.

Design and initial characterization of MIC4, the monolithic active pixel sensor prototype for CEPC vertex detector

The Circular Electron Positron Collider (CEPC) is proposed as a Higgs factory to produce adequate events, which are the basis for high-precision measurements of the Higgs boson. The vertex detector in the CEPC should meet the requirements of a low material budget, high spatial resolution, fast readout speed and low power consumption. A monolithic active pixel sensor (MAPS) has been selected as the most promising technology for the vertex detector. The MIC4 sensor is the first prototype developed within the preliminary R&D activities of the CEPC vertex detector. It has been implemented in the TowerJazz 180 nm CMOS image sensor (CIS) process. It measures 3.1 mm × 4.6 mm and features a 128 row × 64 column pixel array with a pixel pitch of 25μm. In this work, a binary front-end has been designed for a compact pixel combined with a sparsified readout circuitry. Each pixel is composed of an amplifier, a shaper, a discriminator and digital logic. A new asynchronous zero-suppression data-driven readout circuit architecture is proposed and implemented in MIC4. We have performed some initial tests on this chip and obtained detailed results. The front-end features a peaking time below 1μs, a shaping time less than 3μs, a charge threshold of approximately 100 e−, an average temporal noise (TN) of 6 e− and a fixed pattern noise (FPN) of 36 e−. The addresses of the fired pixels can be readout in the digital part of the chip at a clock running at 30 MHz with the new data-driven readout circuit architecture. The hit map under 55Fe X-ray exposure shows that the sensor designed in MIC4 works well. The probability of single event latch-up (SEL) σSEL is 1.02 × 10−6 cm2 at a linear energy transfer (LET) of 20.05 MeV cm2/mg.

Design optimization of a pixel-based range telescope for proton computed tomography

PurposeA pixel-based range telescope for tracking particles during proton imaging is described. The detector applies a 3D matrix of stacked Monolithic Active Pixel Sensors with fast readout speeds. This study evaluates different design alternatives of the range telescope on basis of the protons’ range accuracy and the track reconstruction efficiency. MethodDetector designs with different thicknesses of the energy-absorbing plates between each sensor layer are simulated using the GATE/Geant4 Monte Carlo software. Proton tracks traversing the detector layers are individually reconstructed, and a Bragg curve fitting procedure is applied for the calculation of each proton’s range. ResultsSimulations show that the setups with 4 mm and thinner absorber layers of aluminum have a low range uncertainty compared to the physical range straggling, systematic errors below 0.3 mm water equivalent thickness and a track reconstruction capability exceeding ten million protons per second. ConclusionsIn order to restrict the total number of layers and to yield the required tracking and range resolution properties, a design recommendation is reached where the proposed range telescope applies 3.5 mm thick aluminum absorber slabs between each sensor layer.

Static Random Access Memory Characteristics of Single-Gated Feedback Field-Effect Transistors

In this paper, we propose a novel static random access memory (SRAM) unit cell design and its array structure consisting of single-gated feedback field-effect transistors (FBFETs). To verify the SRAM characteristics, the basic memory operations and write disturbances of the unit cell are investigated through the mixed-mode technology computer-aided design simulations. The unit cell exhibits the superior SRAM characteristics including a write speed of 0.6 ns, a fast read-out speed of ~0.1 ns, and a retention time of 3600 s. Furthermore, the unit cell design exhibits advantages in density, with a small cell area of 8F2, and in the power consumption; the standby power consumption is 0.24 nW/bit for holding “1” and negligible for holding “0.” Moreover, our SRAM array shows reliable ${3} \times {3}$ array operations without any disturbances. This paper demonstrates the promising potential of the FBFET SRAM for high-performance, high-density, and low-power memory applications.

Coupling Laser Diode Thermal Desorption with Acoustic Sample Deposition to Improve Throughput of Mass Spectrometry–Based Screening

The move toward label-free screening in drug discovery has increased the demand for mass spectrometry (MS)–based analysis. Here we investigated the approach of coupling acoustic sample deposition (ASD) with laser diode thermal desorption (LDTD)–tandem mass spectrometry (MS/MS). We assessed its use in a cytochrome P450 (CYP) inhibition assay, where a decrease in metabolite formation signifies CYP inhibition. Metabolite levels for 3 CYP isoforms were measured as CYP3A4-1′-OH-midazolam, CYP2D6-dextrorphan, and CYP2C9-4′-OH-diclofenac. After incubation, samples (100 nL) were acoustically deposited onto a stainless steel 384-LazWell plate, then desorbed by an infrared laser directly from the plate surface into the gas phase, ionized by atmospheric pressure chemical ionization (APCI), and analyzed by MS/MS. Using this method, we achieved a sample analysis speed of 2.14 s/well, with bioanalytical performance comparable to the current online solid-phase extraction (SPE)–based MS method. An even faster readout speed was achieved when postreaction sample multiplexing was applied, where three reaction samples, one for each CYP, were transferred into the same well of the LazWell plate. In summary, LDTD coupled with acoustic sample deposition and multiplexing significantly decreased analysis time to 0.7 s/sample, making this MS-based approach feasible to support high-throughput screening (HTS) assays.

Ultrafast photon counting applied to resonant scanning STED microscopy.

To take full advantage of fast resonant scanning in super-resolution stimulated emission depletion (STED) microscopy, we have developed an ultrafast photon counting system based on a multigiga sample per second analogue-to-digital conversion chip that delivers an unprecedented 450 MHz pixel clock (2.2 ns pixel dwell time in each scan). The system achieves a large field of view (∼50 × 50 μm) with fast scanning that reduces photobleaching, and advances the time-gated continuous wave STED technology to the usage of resonant scanning with hardware-based time-gating. The assembled system provides superb signal-to-noise ratio and highly linear quantification of light that result in superior image quality. Also, the system design allows great flexibility in processing photon signals to further improve the dynamic range. In conclusion, we have constructed a frontier photon counting image acquisition system with ultrafast readout rate, excellent counting linearity, and with the capacity of realizing resonant-scanning continuous wave STED microscopy with online time-gated detection.

Integration and first data with a Pilatus3 6M at APS beamline 23ID-D

GM/CA@APS operates two insertion-device beamlines, 23ID-B and 23ID-D, and one bending magnet beamline, 23BM-B, in sector 23 of the Advanced Photon Source. We recently integrated a Pilatus3 6M detector - a new generation of large sensitive area detectors based on pixel array detector technology and marketed by Dectris. The sensitive area of the device is 423.6 mm × 434.6 mm. The Pilatus3 features the newly implemented re-triggering mechanism that increases the count-rate capabilities by almost an order of magnitude compared to previous generation Pilatus detectors. The detector installed on beamline 23ID-D is the first Pilatus3 6M with a 1000-micron thick sensor, offering higher efficiency at energies above 12 keV. The fast read-out (0.95 ms) and high speed (up to 100 Hz) of the detector allow shutterless data collection. The detector has been fully integrated into the JBluIce user interface and data processing pipeline at GM/CA. Systematic studies with protein crystals were carried out in order to optimize data collection parameters. Overall data collection speed (frame rate), oscillation width per frame, spindle axis speed, and re-triggering have been studied. Different sets of optimal parameters have been established for crystallographic data collection and for crystal screening with the raster feature (grid scanning). The results of these studies and of performance measurements will be presented. This project and GM/CA @ APS are supported by the National Institute of General Medical Sciences and Cancer Institute of NIH.

Profiling Cancer Cell Intrinsic Fluorescence with the Spectral Camera- Phasor Analysis Method

Advances in hyper- or multi-spectral based imaging cameras have expanded new areas of cellular research for the last 20 years. Most recently, intensity signals can now be detected with a line spectrograph in which light is transmited over an imaging signal to an ultra sensitive CCD camera with fast readout speed. However, spectrally resolving these images is highly problematic given that most fluorescent emission spectra are broad and superimposed one with another. In order to spectrally resolve these images with high spectral resolution, we have developed the phasor analysis, used in the first and second harmonic, where each pixel in the image is used to construct a spectral profile that is Fourier transformed to produce the co-ordinates of the pixel in a polar plot. This graphical representation is free of fitting routines and can easily separate linear combinations of multiple spectral components. For this application we used the Andor's iXon Ultra EMCCD camera to obtain spectral emission of cancer cell autofluorescence excited with a multiphoton laser source. Using the multispectral phasor analysis we have been able to identify autofluorescence of cell membrane, mitochondria, nucleus and other organelles. Given the complexity of these biochemical species, we treated the cells with various agents used to perturb metabolic states, membrane fluidity and cellular function to identify changes in spectroscopic signals. A map of these chemical species can provide important information to identify proliferation, stress and dysplasia at the single cell level and can be applied to in the study of cancer and other diseases. Work supported in part by NIH grants P50 GM076516 and P41 GM103540.

The Belle II pixel vertex detector

SuperKEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8 × 1035cm−2s−1 luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. The physics goals of the planned Belle II experiment require a vertex detector with unprecedented performance. The main issues are a high spatial resolution of a few micrometers, a high granularity, and a fast readout speed to cope with the expected high hit occupancy.

Polycrystalline Mercuric Iodide Films on CMOS Readout Arrays

We have created high-resolution x-ray imaging devices using polycrystalline mercuric iodide (HgI(2)) films grown directly onto CMOS readout chips using a thermal vapor transport process. Images from prototype 400x400 pixel HgI(2)-coated CMOS readout chips are presented, where the pixel grid is 30 mum x 30 mum. The devices exhibited sensitivity of 6.2 muC/Rcm(2) with corresponding dark current of approximately 2.7 nA/cm(2), and a 80 mum FWHM planar image response to a 50 mum slit aperture. X-ray CT images demonstrate a point spread function sufficient to obtain a 50 mum spatial resolution in reconstructed CT images at a substantially reduced dose compared to phosphor-coated readouts. The use of CMOS technology allows for small pixels (30 mum), fast readout speeds (8 fps for a 3200x3200 pixel array), and future design flexibility due to the use of well-developed fabrication processes.

Selenium-based amorphous silicon flat-panel digital X-ray imager for protein crystallography

This work proposes a large-area detector for protein crystallography based on an amorphous silicon (a-Si:H) thin film transistor (TFT) pixel-array backplane and an overlying amorphous selenium (a-Se) photoconductor for direct conversion of incident X-rays into an image charge. To achieve high sensitivity, avalanche multiplication in a-Se is adopted to make the detector sensitive to each incident X-ray. The use of a-Si:H technology enables large-area imaging of protein diffraction patterns at less expense compared to existing charge coupled device (CCD) and imaging plate (IP) detectors. In addition, a theoretical analysis shows that the detector exhibits fast readout speed (readout time <1 s), high dynamic range (~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> ), high sensitivity (~1 X-ray photon), and high detective quantum efficiency (~0.7), thus validating its suitability for protein crystallography.

The Katzman Automatic Imaging Telescope Gamma‐Ray Burst Alert System, and Observations of GRB 020813

ABSTRACTWe present the technical details of the gamma‐ray burst (GRB) alert system of the Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory and the successful observations of the GRB 020813 optical afterglow with this system. KAIT responds to GRB alerts robotically, interrupts its prearranged program, and takes a sequence of images for each GRB alert. A grid‐imaging procedure is used to increase the efficiency of the early‐time observations. Different sequences of images have been developed for different types of GRB alerts. With relatively fast telescope slew and CCD readout speed, KAIT can typically complete the first observation within 60 s after receiving a GRB alert, reaching a limiting magnitude of ∼19. Our reduction of the GRB 020813 data taken with KAIT shows that unfiltered magnitudes can be reliably transformed to a standard passband with a precision of ∼5%, given that the color of the object is known. The GRB 020813 optical afterglow has an exceptionally slow early‐time power‐law decay index, although other light‐curve parameters and the optical spectral index are fairly typical of GRBs.

An asynchronous, pipelined, electronic acquisition system for Active Matrix Flat-Panel Imagers (AMFPIs)

The development of a full-custom electronic acquisition system designed for readout of large-area active matrix flat-panel imaging arrays is reported. The arrays, which comprise two-dimensional matrices of pixels utilizing amorphous silicon thin-film transistors, are themselves under development for a wide variety of X-ray imaging applications. The acquisition system was specifically designed to facilitate detailed, quantitative investigations of the properties of these novel imaging arrays and contains significant enhancements compared to a previously developed acquisition system. These enhancements include pipelined preamplifier circuits to allow faster readout speed, expanded addressing capabilities allowing a maximum of 4096 array data lines, and on-board summing of image frames. The values of many acquisition system parameters, including timings and voltages, may be specified and downloaded from a host computer. Once acquisition is enabled, the system operates asynchronously of its host computer. The system allows image capture in both radiographic mode (corresponding to the capture of individual X-ray images), and fluoroscopic mode (corresponding to the capture of a continual series of X-ray images). A detailed description of the system architecture and the underlying motivations for the design is reported in this paper.