Parallel Readout Research Articles

Noise reduction effect and analysis through serial multiple sampling in a CMOS image sensor with floating diffusion boost-driving

We have developed a 1/2.3-in. 10.3 mega pixel back-illuminated CMOS image sensor utilizing serial multiple sampling. This sensor achieves an RMS random noise of 1.3e− and row temporal noise (RTN) of 0.19e−. Serial multiple sampling is realized with a column inline averaging technique without the need for additional processing circuitry. Pixel readout is accomplished utilizing a 4-shared-pixel floating diffusion (FD) boost-driving architecture. RTN caused by column parallel readout was analyzed considering the transfer function at the system level and the developed model was verified by measurement data taken at each sampling time. This model demonstrates the RTN improvement of −1.6 dB in a parallel multiple readout architecture.

Development of a low-noise readout ASIC for Silicon Drift Detectors in high energy resolution X-ray spectrometry

ASIC with a low-noise readout channel for Silicon Drift Detectors in high energy resolution X-ray spectrometry was designed and prototyped in the AMS 350 nm CMOS process via Europractice as a miniASIC. For the analog readout channel tests there was used the detector module SDD-10-130-PTW LTplus-ic (PNDetector GmbH). The measured energy resolution of this module with the designed readout channel: 200 eV (FWHM) at 55Fe, -16 °C, 1 kcps and a peaking time of 8 μs.

Electron energy loss spectroscopy with parallel readout of energy and momentum.

We introduce a high energy resolution electron source that matches the requirements for parallel readout of energy and momentum of modern hemispherical electron energy analyzers. The system is designed as an add-on device to typical photoemission chambers. Due to the multiplex gain, a complete phonon dispersion of a Cu(111) surface was measured in 7 min with 4 meV energy resolution.

Improving Performance of Analogue Readout Layers for Photonic Reservoir Computers with Online Learning

Reservoir Computing is a bio-inspired computing paradigm for processing time-dependent signals (Jaeger and Haas 2004; Maass, Natschläger, and Markram 2002). The performance of its hardware implementation (see e.g. (Soriano et al. 2015) for a review) is comparable to state-of-the-art digital algorithms on a series of benchmark tasks.The major bottleneck of these implementation is the readout layer, based on slow offline post-processing. Several analogue solutions have been proposed (Smerieri et al. 2012; Duport et al. 2016; Vinckier et al. 2016), but all suffered from noticeable decrease in performance due to added complexity of the setup. Here we propose the online learning approach to solve these issues. We present an experimental reservoir computer with a simple analogue readout layer, based on previous works, and show numerically that online learning allows to disregard the added complexity of an analogue layer and obtain the same level of performance as with a digital layer. This work thus demonstrates that online training allows building high-performance fully-analogue reservoir computers, and represents an important step towards experimental validation of the proposed solution.

An Electrical-Stimulus-Only BIST IC for Capacitive MEMS Accelerometer Sensitivity Characterization

Testing and calibration constitute a major part of the overall manufacturing cost of microelectromechanical system (MEMS) devices. A physical-stimulus-free built-in-self-test (BIST) integrated circuit (IC) design characterizing the sensitivity of capacitive MEMS accelerometers is presented. The BIST circuitry can extract the amplitude and phase response of the acceleration sensor’s mechanics under electrical excitation within 0.55% of error with respect to its mechanical sensitivity under physical stimulus. Sensitivity characterization is performed using a low computational complexity multi-variate linear regression model. The BIST circuitry maximizes the use of existing analog and mixed signal readout signal chain and the host processor core, without the need for computationally expensive fast Fourier transform (FFT)-based approaches. The BIST IC is designed and fabricated using the 0.18- $\mu \text{m}$ CMOS technology. The sensor analog front-end and BIST circuitry is integrated with a three axis, low- $g$ capacitive MEMS accelerometer in a single hermetically sealed package. The BIST circuitry occupies 0.3 mm $^{ { {2}}}$ with a total readout IC area of 1 mm $^{ { {2}}}$ , and consumes 8.9 mW during self-test operation.

Measurements with MÖNCH, a 25 μm pixel pitch hybrid pixel detector

MÖNCH is a hybrid silicon pixel detector based on charge integration and with analog readout, featuring a pixel size of 25×25 μm2. The latest working prototype consists of an array of 400×400 identical pixels for a total active area of 1×1 cm2. Its design is optimized for the single photon regime. An exhaustive characterization of this large area prototype has been carried out in the past months, and it confirms an ENC in the order of 35 electrons RMS and a dynamic range of ∼4×12 keV photons in high gain mode, which increases to ∼100×12 keV photons with the lowest gain setting. The low noise levels of MÖNCH make it a suitable candidate for X-ray detection at energies around 1 keV and below. Imaging applications in particular can benefit significantly from the use of MÖNCH: due to its extremely small pixel pitch, the detector intrinsically offers excellent position resolution. Moreover, in low flux conditions, charge sharing between neighboring pixels allows the use of position interpolation algorithms which grant a resolution at the micrometer-level. Its energy reconstruction and imaging capabilities have been tested for the first time at a low energy beamline at PSI, with photon energies between 1.75 keV and 3.5 keV, and results will be shown.

Selective addressing and readout of optically detected electron spins

Optically detected magnetic resonance (ODMR) is known to allow the ultrasensitive detection of a small number of electron spins for species such as nitrogen vacancy (NV) centers in diamond, down to the single spin level. This method was recently combined with the pulsed magnetic resonance imaging (MRI) technique known as optically detected magnetic resonance imaging (ODMRI) to obtain images of NVs at resolutions ranging from the micron- to the nanoscale. The great advantage of ODMRI is that the quantum state of the spins can be acquired (i.e., readout) in parallel from all parts of the sample without any loss of spectroscopic information. Here we further enhance the utility of our ODMRI technique by improving its spatial resolution and adding a spatially selective spin addressing and manipulation capability. We demonstrate this capability by selectively manipulating a specific group of spins in our sample and subsequently imaging the entire sample to show this selectivity effect. Such capabilities are of fundamental importance in the field of spin-based quantum devices and sensors.

Development of an analog read-out channel for time projection chambers

The development of an analog read-out channel for time projection chambers (TPC) is presented both in schematic and layout. Structure of the channel consists of a preamplifier, fourth order shaper and differential buffer. The channel operates with positive and negative polarities of input charge. The prototype has the following features: dynamic range of 100 fC for both polarities, 20 mv/fC of sensitivity for differential output, peaking time – 160 ns, ENC - <1000e at 40 pF of source capacitance. The presented channel was designed and verified in the CMOS UMC MMRF 180 nm process. The results of post layout simulation are presented.

A Design of a New Column-Parallel Analog-to-Digital Converter Flash for Monolithic Active Pixel Sensor.

The CMOS Monolithic Active Pixel Sensor (MAPS) for the International Linear Collider (ILC) vertex detector (VXD) expresses stringent requirements on their analog readout electronics, specifically on the analog-to-digital converter (ADC). This paper concerns designing and optimizing a new architecture of a low power, high speed, and small-area 4-bit column-parallel ADC Flash. Later in this study, we propose to interpose an S/H block in the converter. This integration of S/H block increases the sensitiveness of the converter to the very small amplitude of the input signal from the sensor and provides a sufficient time to the converter to be able to code the input signal. This ADC is developed in 0.18 μm CMOS process with a pixel pitch of 35 μm. The proposed ADC responds to the constraints of power dissipation, size, and speed for the MAPS composed of a matrix of 64 rows and 48 columns where each column ADC covers a small area of 35 × 336.76 μm2. The proposed ADC consumes low power at a 1.8 V supply and 100 MS/s sampling rate with dynamic range of 125 mV. Its DNL and INL are 0.0812/−0.0787 LSB and 0.0811/−0.0787 LSB, respectively. Furthermore, this ADC achieves a high speed more than 5 GHz.

Optically active semiconductor nanopores for parallel molecule detection

We propose a detection scheme for charged molecules or particles based on optically excited semiconductor nanopores. By means of numerical simulations, we show that the band gap of the semiconductor nanopore can be tuned allowing actuation by light. Molecules translocating through the semiconductor nanopore modulate the fluorescence from the nanopore enabling molecule detection. Our approach will enable us to perform a parallel readout of a translocating molecule without the need of chemical modification of the translocating molecules.

Preliminary conceptual design about the CEPC calorimeters

The Circular Electron Positron Collider (CEPC) as a Higgs factory was proposed in September 2013. The preliminary conceptual design report was completed in 2015.1 The CEPC detector design was using International Linear Collider Detector — ILD2 as an initial baseline. The CEPC calorimeters, including the high granularity electromagnetic calorimeter (ECAL) and the hadron calorimeter (HCAL), are designed for precise energy measurements of electrons, photons, taus and hadronic jets. The basic resolution requirements for the ECAL and HCAL are about 16%[Formula: see text][Formula: see text] (GeV) and 50%[Formula: see text][Formula: see text] (GeV), respectively. To fully exploit the physics potential of the Higgs, [Formula: see text], [Formula: see text] and related Standard Model processes, the jet energy resolution is required to reach 3%–4%, or 30%/[Formula: see text] (GeV) at energies below about 100 GeV. To achieve the required performance, a Particle Flow Algorithm (PFA) — oriented calorimetry system is being considered as the baseline design. The CEPC ECAL detector options include silicon–tungsten or scintillator–tungsten structures with analog readout, while the HCAL detector options have scintillator or gaseous detector as the active sensor and iron as the absorber. Some latest R&amp;D studies about ECAL and HCAL within the CEPC working group is also presented.

Silicon pixel-detector R&D for CLIC

The physics aims at the future CLIC high-energy linear e+e- collider set very high precision requirements on the performance of the vertex and tracking detectors. Moreover, these detectors have to be well adapted to the experimental conditions, such as the time structure of the collisions and the presence of beam-induced backgrounds. The principal challenges are: a point resolution of a few μm, ultra-low mass (∼ 0.2%X0 per layer for the vertex region and ∼ 1%X0 per layer for the outer tracker), very low power dissipation (compatible with air-flow cooling in the inner vertex region) and pulsed power operation, complemented with ∼ 10 ns time stamping capabilities. A highly granular all-silicon vertex and tracking detector system is under development, following an integrated approach addressing simultaneously the physics requirements and engineering constraints. For the vertex-detector region, hybrid pixel detectors with small pitch (25 μm) and analog readout are explored. For the outer tracking region, both hybrid concepts and fully integrated CMOS sensors are under consideration. The feasibility of ultra-thin sensor layers is validated with Timepix3 readout ASICs bump bonded to active edge planar sensors with 50 μm to 150 μm thickness. Prototypes of CLICpix readout ASICs implemented in 6525 nm CMOS technology with 25 μm pixel pitch have been produced. Hybridisation concepts have been developed for interconnecting these chips either through capacitive coupling to active HV-CMOS sensors or through bump-bonding to planar sensors. Recent R&D achievements include results from beam tests with all types of hybrid assemblies. Simulations based on Geant4 and TCAD are used to validate the experimental results and to assess and optimise the performance of various detector designs.

Report on recent results of the PERCIVAL soft X-ray imager

The PERCIVAL (Pixelated Energy Resolving CMOS Imager, Versatile And Large) soft X-ray 2D imaging detector is based on stitched, wafer-scale sensors possessing a thick epi-layer, which together with back-thinning and back-side illumination yields elevated quantum efficiency in the photon energy range of 125–1000 eV. Main application fields of PERCIVAL are foreseen in photon science with FELs and synchrotron radiation. This requires high dynamic range up to 105 ph @ 250 eV paired with single photon sensitivity with high confidence at moderate frame rates in the range of 10–120 Hz. These figures imply the availability of dynamic gain switching on a pixel-by-pixel basis and a highly parallel, low noise analog and digital readout, which has been realized in the PERCIVAL sensor layout. Different aspects of the detector performance have been assessed using prototype sensors with different pixel and ADC types. This work will report on the recent test results performed on the newest chip prototypes with the improved pixel and ADC architecture. For the target frame rates in the 10–120 Hz range an average noise floor of 14e− has been determined, indicating the ability of detecting single photons with energies above 250 eV. Owing to the successfully implemented adaptive 3-stage multiple-gain switching, the integrated charge level exceeds 4 · 106 e− or 57000 X-ray photons at 250 eV per frame at 120 Hz. For all gains the noise level remains below the Poisson limit also in high-flux conditions. Additionally, a short overview over the updates on an oncoming 2 Mpixel (P2M) detector system (expected at the end of 2016) will be reported.

Diffusion Tractography of the Entire Left Ventricle by Using Free-breathing Accelerated Simultaneous Multisection Imaging.

Purpose To develop a clinically feasible whole-heart free-breathing diffusion-tensor (DT) magnetic resonance (MR) imaging approach with an imaging time of approximately 15 minutes to enable three-dimensional (3D) tractography. Materials and Methods The study was compliant with HIPAA and the institutional review board and required written consent from the participants. DT imaging was performed in seven healthy volunteers and three patients with pulmonary hypertension by using a stimulated echo sequence. Twelve contiguous short-axis sections and six four-chamber sections that covered the entire left ventricle were acquired by using simultaneous multisection (SMS) excitation with a blipped-controlled aliasing in parallel imaging readout. Rate 2 and rate 3 SMS excitation was defined as two and three times accelerated in the section axis, respectively. Breath-hold and free-breathing images with and without SMS acceleration were acquired. Diffusion-encoding directions were acquired sequentially, spatiotemporally registered, and retrospectively selected by using an entropy-based approach. Myofiber helix angle, mean diffusivity, fractional anisotropy, and 3D tractograms were analyzed by using paired t tests and analysis of variance. Results No significant differences (P > .63) were seen between breath-hold rate 3 SMS and free-breathing rate 2 SMS excitation in transmural myofiber helix angle, mean diffusivity (mean ± standard deviation, [0.89 ± 0.09] × 10-3 mm2/sec vs [0.9 ± 0.09] × 10-3 mm2/sec), or fractional anisotropy (0.43 ± 0.05 vs 0.42 ± 0.06). Three-dimensional tractograms of the left ventricle with no SMS and rate 2 and rate 3 SMS excitation were qualitatively similar. Conclusion Free-breathing DT imaging of the entire human heart can be performed in approximately 15 minutes without section gaps by using SMS excitation with a blipped-controlled aliasing in parallel imaging readout, followed by spatiotemporal registration and entropy-based retrospective image selection. This method may lead to clinical translation of whole-heart DT imaging, enabling broad application in patients with cardiac disease. © RSNA, 2016 Online supplemental material is available for this article.

Parallel Read-Out and Database Search With Magnonic Holographic Memory

In this paper, we present the most recent results on the development of magnonic holographic memory (MHM). MHM is a type of holographic device, which uses spin waves for data transfer and processing. The most appealing properties of MHM include parallel read-out and database search. We present experimental data showing parallel read-out of four magnetic memory states. In this experiment, the internal magnetic state is recognized by the level of the output inductive voltage produced by the spin-wave interference. We also present the experimental data showing database search in the MHM. In this experiment, the search for the maximum output is accomplished by utilizing spin-wave superposition. The experiments were carried out for six- and eight-terminal yttrium iron garnet-based prototypes. Potentially, magnonic holographic devices can be implemented as complementary memory/logic units to digital processors. Physical limitations and technological constraints of the spin-wave approach are also discussed.

Demonstration of Convolution Kernel Operation on Resistive Cross-Point Array

Convolution is the key operation in the convolutional neural network, one of the most popular deep learning algorithms. The implementation of the convolution kernel on the resistive cross-point array is different than the implementation of the matrix-vector multiplication in prior works. In this letter, we propose a dimensional reduction of 2-D kernel matrix into 1-D column vector, i.e., a column of the array, and enable the parallel readout of multiple 2-D kernels simultaneously. As a proof-of-concept demonstration, we use the Prewitt kernels to detect both horizontal and vertical edges of the $20 \times 20$ pixels of black-and-white MNIST handwritten digits. The experiments were performed on the fabricated $12 \times 12$ resistive cross-point array based on the Pt/HfO x /TiN structure. The experimental results of the Prewitt kernel operation perfectly matches the simulation results, indicating the feasibility of the proposed implementation methodology of the convolution kernel on resistive cross-point array.

RedEye

Continuous mobile vision is limited by the inability to efficiently capture image frames and process vision features. This is largely due to the energy burden of analog readout circuitry, data traffic, and intensive computation. To promote efficiency, we shift early vision processing into the analog domain. This results in RedEye, an analog convolutional image sensor that performs layers of a convolutional neural network in the analog domain before quantization. We design RedEye to mitigate analog design complexity, using a modular column-parallel design to promote physical design reuse and algorithmic cyclic reuse. RedEye uses programmable mechanisms to admit noise for tunable energy reduction. Compared to conventional systems, RedEye reports an 85% reduction in sensor energy, 73% reduction in cloudlet-based system energy, and a 45% reduction in computation-based system energy.

The MuPix system-on-chip for the Mu3e experiment

Mu3e is a novel experiment searching for charged lepton flavor violation in the rare decay μ+→e+e−e+. Decay vertex position, decay time and particle momenta have to be precisely measured in order to reject both accidental and physics background. A silicon pixel tracker based on 50μm thin high voltage monolithic active pixel sensors (HV-MAPS) in a 1T solenoidal magnetic field provides precise vertex and momentum information. The MuPix chip combines pixel sensor cells with integrated analog electronics and a periphery with a complete digital readout. The MuPix7 is the first HV-MAPS prototype implementing all functionalities of the final sensor including a readout state machine and high speed serialization with 1.25Gbit/s data output, allowing for a streaming readout in parallel to the data taking. The observed efficiency of the MuPix7 chip including the full readout system is ⩾99% in a high rate test beam.

P-stop isolation study of irradiated n-in-p type silicon strip sensors for harsh radiation environments

In order to determine the most radiation hard silicon sensors for the CMS Experiment after the Phase II Upgrade in 2023 a comprehensive study of silicon sensors after a fluence of up to 1.5×1015neq/cm2 corresponding to 3000fb−1 after the HL-LHC era has been carried out. The results led to the decision that the future Outer Tracker (20cm<R<110cm) of CMS will consist of n-in-p type sensors. This technology is more radiation hard but also the manufacturing is more challenging compared to p-in-n type sensors due to additional process steps in order to suppress the accumulation of electrons between the readout strips. One possible isolation technique of adjacent strips is the p-stop structure which is a p-type material implantation with a certain pattern for each individual strip. However, electrical breakdown and charge collection studies indicate that the process parameters of the p-stop structure have to be carefully calibrated in order to achieve a sufficient strip isolation but simultaneously high breakdown voltages. Therefore a study of the isolation characteristics with four different silicon sensor manufacturers has been executed in order to determine the most suitable p-stop parameters for the harsh radiation environment during HL-LHC. Several p-stop doping concentrations, doping depths and different p-stop pattern have been realized and experiments before and after irradiation with protons and neutrons have been performed and compared to T-CAD simulation studies with Synopsys Sentaurus. The measurements combine the electrical characteristics measured with a semi-automatic probestation with Sr90 signal measurements and analogue readout. Furthermore, some samples have been investigated with the help of a cosmic telescope with high resolution allowing charge collection studies of MIPs penetrating the sensor between two strips.

Study and optimization of the spatial resolution for detectors with binary readout

Using simulations and analytical approaches, we have studied single hit resolutions obtained with a binary readout, which is often proposed for high granularity detectors to reduce the generated data volume. Our simulations considering several parameters (e.g. strip pitch) show that the detector geometry and an electronics parameter of the binary readout chips could be optimized for binary readout to offer an equivalent spatial resolution to the one with an analog readout. To understand the behavior as a function of simulation parameters, we developed analytical models that reproduce simulation results with a few parameters. The models can be used to optimize detector designs and operation conditions with regard to the spatial resolution.