Precise Time Resolution Research Articles

PICOSEC-Micromegas Detector, an innovative solution for Lepton Time Tagging

The PICOSEC-Micromegas (PICOSEC-MM) detector is a novel gaseous detector designed for precise timing resolution in experimental measurements. It eliminates time jitter from charged particles in ionization gaps by using extreme UV Cherenkov light emitted in a crystal, detected by a Micromegas photodetector with an appropriate photocathode. The first single-channel prototype tested in 150 GeV/c muon beams achieved a timing resolution below 25 ps, a significant improvement compared to standard Micropattern Gaseous Detectors (MPGDs). This work explores the specifications for applying these detectors in monitored neutrino beams for the ENUBET Project. Key aspects include exploring resistive technologies, resilient photocathodes, and scalable electronics. New 7-pad resistive detectors are designed to handle the particle flux. In this paper, two potential scenarios are briefly considered: tagging electromagnetic showers with a timing resolution below 30ps in an electromagnetic calorimeter as well as individual particles (mainly muons) with about 20ps respectively.

Characterization of the BigRock 28 nm fast timing Analog Front End

An initial characterization of the BigRock high-speed, low-power Analog Front End (AFE) is presented. The BigRock AFE previously described in [1] has been refined in a second generation testbed ASIC, Pebbles. The AFE utilizes a current-mode signal path that has been designed for 4D tracking applications with precision time resolution of order 50 ps. The preamplifier concept is based on a prior art current-feedback CMOS topology in [2]. An on-chip test bench comprised of a variable injection circuit and high-resolution TDC measures the AFE timing resolution. An array of integrated load capacitors and IO IPs enhance the characterization capability. These full-custom pads include LVDS and clock receivers, CML output driver, and simple analog buffer pads designed at the process core voltage (0.9 V) on a 90 μm/180 μm pitch. Critical noise and timing metrics for an array of input detector capacitance ranging 0 to 100 fF have been measured.

A paintbrush for delivery of nanoparticles and molecules to live cells with precise spatiotemporal control

Delivery of very small amounts of reagents to the near-field of cells with micrometer spatial precision and millisecond time resolution is currently out of reach. Here we present μkiss as a micropipette-based scheme for brushing a layer of small molecules and nanoparticles onto the live cell membrane from a subfemtoliter confined volume of a perfusion flow. We characterize our system through both experiments and modeling, and find excellent agreement. We demonstrate several applications that benefit from a controlled brush delivery, such as a direct means to quantify local and long-range membrane mobility and organization as well as dynamical probing of intercellular force signaling.

The commissioning status of the intermediate silicon tracker of sPHENIX

The sPHENIX project is a new collider experiment at the Relativistic Heavy Ion Collider (RHIC) in Brookhaven National Laboratory (BNL). It aims to study the Quark-Gluon Plasma and cold Quantum Chromodynamics (QCD) by measuring photons, jets, jet correlations, and the Upsilon family with high precision. To achieve these goals, a precise tracking system is necessary. The tracking system of the sPHENIX detector consists of the MVTX, INTT, TPC, and TPOT. INTT is a two-layer barrel silicon tracker that plays a unique role among the sPHENIX tracking detectors. It is capable of bridging the tracks of MVTX and TPC. In addition, its precise timing resolution enables INTT to associate individual tracks with events to eliminate pile-up events. The INTT barrel installation and cabling were completed in March 2023. We have since commissioned and confirmed the detector responses. The INTT status, and performance evaluated by beam and cosmic rays are described in this proceedings.

Development of a precise time and position resolution TOF-tracker MRPC for the [formula omitted]20 beam line at J-PARC

We are developing time-of-flight (TOF) multi-gap Resistive Plate Chambers (MRPCs) which perform both timing and hit position measurements, the TOF-tracker MRPC, for muon detection to measure exclusive Drell–Yan reaction (π−p→γ∗n→μ+μ−n) at J-PARC’s hadron hall. Here we report on the development of a prototype TOF-tracker MRPC with a sensitive area of 500×1000mm2 and its performance in an electron-positron particle beam at the SPring-8 synchrotron in Japan.

Mid-infrared single-photon 3D imaging

Active mid-infrared (MIR) imagers capable of retrieving three-dimensional (3D) structure and reflectivity information are highly attractive in a wide range of biomedical and industrial applications. However, infrared 3D imaging at low-light levels is still challenging due to the deficiency of sensitive and fast MIR sensors. Here we propose and implement a MIR time-of-flight imaging system that operates at single-photon sensitivity and femtosecond timing resolution. Specifically, back-scattered infrared photons from a scene are optically gated by delay-controlled ultrashort pump pulses through nonlinear frequency upconversion. The upconverted images with time stamps are then recorded by a silicon camera to facilitate the 3D reconstruction with high lateral and depth resolutions. Moreover, an effective numerical denoiser based on spatiotemporal correlation allows us to reveal the object profile and reflectivity under photon-starving conditions with a detected flux below 0.05 photons/pixel/second. The presented MIR 3D imager features high detection sensitivity, precise timing resolution, and wide-field operation, which may open new possibilities in life and material sciences.

Optimization of capacitively coupled Low Gain Avalanche Diode (AC-LGAD) sensors for precise time and spatial resolution

Capacitively-coupled Low-Gain Avalanche Diode (AC-LGAD) sensors are being developed for high-energy particle physics experiments as a detector which provides fast time information with fine spatial resolution. This paper describes optimizations of AC-LGAD sensor fabrication parameters, such as doping concentrations of the gain and electrode layers as well as the AC insulator capacitance, to realize O(10) μm spatial resolution, small charge cross talk to the neighboring electrodes, detection efficiency higher than 99% at a 10−4 noise rate and time resolution of about 30 ps. The radiation tolerance of the sensor is presented. In addition, further application to a device capable of visible and infra-red light detection is discussed.

Influence of soil density on the solid-to-fluid phase transition in flowslide flume experiments

Flowslides are extremely hazardous due to their sudden failure and rapid flow-like motion. Focusing on the transient solid-to-fluid phase transition, we carried out a series of flume studies following various experimental scenarios, simultaneously recording granular velocity distributions, pore-water pressures, microseismicity, and acoustic emissions with precise time resolution (±0.01 s). The solid-to-fluid phase transition was recognized from the transition from solid-like shear deformation to flow-like velocity distribution. The variation in excess pore pressure in slopes during failure differed depending on initial soil state parameters, resulting in different failure patterns and distinct solid-to-fluid phase transition dynamics: (i) diffuse failure in loose slopes, the soil instability caused by increased local pore pressure (far from liquefaction) can trigger the whole failure of the slope; (ii) Mohr-coulomb failures in denser slopes, the soil mass slid along a localized shear zone, and progressively evolved to a diffuse shear throughout the slide mass. and (iii) retrogressive failures in very dense slopes. During the rapid motion process, the soil mass behaved as a fluid even after the excess pore pressure had dissipated, demonstrating that mechanisms other than soil liquefaction governed the fluid-like behavior. We inferred that the fluidization originated from the inherent shear-rate-dependent behavior of granular materials. Additional evidence for this hypothesis was provided by ultra-high frequency acoustic emissions (approximately 100 kHz) suggesting grain-scale collisions accompanying the fluidized runout.

Feasibility study of a proton CT system based on 4D-tracking and residual energy determination via time-of-flight

Objective. For dose calculations in ion beam therapy, it is vital to accurately determine the relative stopping power (RSP) distribution within the treatment volume. A suitable imaging modality to achieve the required RSP accuracy is proton computed tomography (pCT), which usually uses a tracking system and a separate residual energy (or range) detector to directly measure the RSP distribution. This work investigates the potential of a novel pCT system based on a single detector technology, namely low gain avalanche detectors (LGADs). LGADs are fast 4D-tracking detectors, which can be used to simultaneously measure the particle position and time with precise timing and spatial resolution. In contrast to standard pCT systems, the residual energy is determined via a time-of-flight (TOF) measurement between different 4D-tracking stations. Approach. To show the potential of using 4D-tracking for proton imaging, we studied and optimized the design parameters for a realistic TOF-pCT system using Monte Carlo simulations. We calculated the RSP accuracy and RSP resolution inside the inserts of the CTP404 phantom and compared the results to a simulation of an ideal pCT system. Main results. After introducing a dedicated calibration procedure for the TOF calorimeter, RSP accuracies less than 0.6% could be achieved. We also identified the design parameters with the strongest impact on the RSP resolution and proposed a strategy to further improve the image quality. Significance. This comprehensive study of the most important design aspects for a novel TOF-pCT system could help guide future hardware developments and, once implemented, improve the quality of treatment planning in ion beam therapy.

The CMS electromagnetic calorimeter upgrade: high-rate readout with precise time and energy resolution

The electromagnetic calorimeter (ECAL) of the CMS detector has played an important role in the physics program of the experiment, delivering outstanding performance throughout data taking. The high-luminosity LHC will pose new challenges. The four to five-fold increase of the number of interactions per bunch crossing will require superior time resolution and noise rejection capabilities. For these reasons the electronics readout has been completely redesigned. A dual gain trans-impedance amplifier and an ASIC providing two 160 MHz ADC channels, gain selection, and data compression will be used in the new readout electronics. The trigger decision will be moved off-detector and will be performed by powerful and flexible FPGA processors, allowing for more sophisticated trigger algorithms to be applied. The upgraded ECAL will be capable of high-precision energy measurements throughout HL-LHC and will greatly improve the time resolution for photons and electrons above 10 GeV.

Probing Allosteric Modulation of Membrane Receptor in the Native State by Data Mining-Integrated Tracking Microscopy

Probing Allosteric Modulation of Membrane Receptor in the Native State by Data Mining-Integrated Tracking Microscopy

Targeting the motor cortex to restore walking after incomplete spinal cord injury.

Targeting the motor cortex to restore walking after incomplete spinal cord injury.

Polaris-LAMP: Multi-Modal 3-D Image Reconstruction With a Commercial Gamma-Ray Imager

The Polaris-LAMP multi-modal 3-D gamma-ray imager is a radiation mapping and imaging platform which uses a commercial off-the-shelf (COTS) detector integrated with a contextual sensor localization and mapping platform. The integration of these systems enables a free-moving radiation imaging capability with proximity mapping, coded-aperture, and Compton imaging modalities, which can create 3-D reconstruction of photon sources from tens of keV to several MeV. Gamma-ray events are recorded using a segmented cadmium zinc telluride (CZT) detector (Polaris-H Quad by H3D Inc., Ann Arbor, MI, USA), while scene data are derived from a contextual sensor and computation package developed by Lawrence Berkeley National Laboratory which includes GPS, laser ranging, and inertial measurement sensors. An onboard computer uses these inputs to create rapidly updating pose (10 Hz) and 3-D scene estimates using a simultaneous localization and mapping (SLAM) algorithm. The precise gamma-ray event location and timing resolution of the Polaris CZT sensor enables Compton imaging above several hundred keV, while photon sources at lower images are localized using coded-aperture imaging techniques. The multi-modal imaging concept enables imaging of diverse radiation sources spanning from the 59-keV emission of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">241</sup> Am to the 1.1 and 1.3 MeV lines of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">60</sup> Co. This work focuses on the description of the operational principles of the detector system and demonstrating the 3-D imaging performance in a variety of source detection and mapping scenarios. As a proof of concept, we demonstrate mapping complex environments, including both point source and distributed-source environments using proximity, coded-aperture, and Compton imaging modalities. Furthermore, we show the successful use of the system to perform measurements in high-background environments through analysis of arrays of uranium hexafluoride cylinders at the Paducah UF6 project site.

End-to-end Bayesian analysis for summarizing sets of radiocarbon dates

Archaeologists and demographers increasingly employ aggregations of published radiocarbon (14C) dates as demographic proxies summarizing changes in human activity in past societies. Presently, summed probability densities (SPDs) of calibrated radiocarbon dates are the dominant method of using 14C dates to reconstruct demographic trends. Unfortunately, SPDs are incapable of converging on the distribution that generated a set of radiocarbon measurements, even when the number of observations is large. To overcome this problem, we propose a more principled alternative that combines finite mixture models and end-to-end Bayesian inference. Numerical simulations and an assessment of the statistical identifiability of our method demonstrate that it correctly converges on the generating distribution for two important models, exponentials and finite Gaussian mixtures, at least if the same statistical model is used to fit the data as was used to generate the data. To further validate this approach, we apply it to a set of radiocarbon dates from the Maya city of Tikal. We show that an end-to-end approach reconstructs with high accuracy expert demographic reconstructions based on settlement patterns and ceramics, but with more precise time-resolution and characterization of uncertainty than has heretofore been possible. Future work should consider alternatives to finite Gaussian mixtures for fitting the generating distribution.

Electrostatic Modulation of Signaling at the Membrane Waveform- and Time-Dependent Electric Control of ERK Dynamics

The dynamics of extracellular-signal-regulated kinase (ERK) signaling regulates a wide variety of stimulated cellular processes and plays an important role in cell survival, motility, differentiation and proliferation. Here we show that a new range of alternative current electric field (AC EF) in the tens of KHz could non-invasively activate EGFR-Ras-ERK signaling pathway with precise timing and single-cell resolution, where electroporation or Faradaic processes have been deliberately avoided by using high-k dielectric passivated microelectrodes.

Superconducting nanowire single-photon detectors with 98% system detection efficiency at 1550 nm

Superconducting nanowire single-photon detectors (SNSPDs) are an enabling technology for myriad quantum-optics experiments that require high-efficiency detection, large count rates, and precise timing resolution. The system detection efficiencies (SDEs) for fiber-coupled SNSPDs have fallen short of theoretical predictions of near unity by at least 7%, with the discrepancy being attributed to scattering, material absorption, and other SNSPD dynamics. We optimize the design and fabrication of an all-dielectric layered stack and fiber coupling package in order to achieve 98.0 ± 0.5 % SDE, measured for single-mode-fiber guided photons derived from a highly attenuated 1550 nm continuous-wave laser. This enforces a smaller bound on the scattering and absorption losses in such systems and opens the use of SNSPDs for scenarios that demand high-SDE for throughput and fidelity.

Single-pixel imaging 12 years on: a review.

Modern cameras typically use an array of millions of detector pixels to capture images. By contrast, single-pixel cameras use a sequence of mask patterns to filter the scene along with the corresponding measurements of the transmitted intensity which is recorded using a single-pixel detector. This review considers the development of single-pixel cameras from the seminal work of Duarte et al. up to the present state of the art. We cover the variety of hardware configurations, design of mask patterns and the associated reconstruction algorithms, many of which relate to the field of compressed sensing and, more recently, machine learning. Overall, single-pixel cameras lend themselves to imaging at non-visible wavelengths and with precise timing or depth resolution. We discuss the suitability of single-pixel cameras for different application areas, including infrared imaging and 3D situation awareness for autonomous vehicles.

Distinguishability theory for time-resolved photodetection and boson sampling

We study distinguishability of photons in multiphoton interference on a multiport when fast detectors, capable of precise time resolution, are employed. Such a setup was previously suggested for experimental realization of boson sampling with single photons. We investigate if fast photodetection allows to circumvent distinguishability of realistic single photons in mixed states. To this goal we compare distinguishability of photons in two setups: (a) with photons in the same average (temporal) profile on a spatial interferometer and photodetection incapable of (or with strongly imprecise) time resolution and (b) with photons in generally different average temporal profiles on the same spatial interferometer and photodetection with precise time resolution. Exact analytical results are obtained for Gaussian-shaped single photons with Gaussian distribution of photon arrival time. Distinguishability of photons in the two setups is found to be strikingly similar. For the same purity of photon states, only the same quality experimental boson sampling can be achieved using either of the two setups. The upshot of our results is that distinguishability due to mixed states is an intrinsic property of photons, whatever the photodetection scheme.

Upgrade of the CMS electromagnetic calorimeter for precision timing and energy measurements at the High Luminosity LHC

The high luminosity upgrade of the LHC (HL-LHC) at CERN will provide unprecedented instantaneous and integrated luminosities of around 5 × 1034 cm−2 s−1 and up to 4500 fb−1, respectively, from 2027 to 2035. We predict an average of 140 to 200 concurrent interactions per bunch crossing (pile-up). This poses a major challenge to the event reconstruction. The Compact Muon Solenoid (CMS) detector is therefore undergoing an extensive Phase II upgrade program to prepare for these challenging conditions. The upgrade of the barrel part of the CMS electromagnetic calorimeter (ECAL) for HL-LHC will extend the detector performance to be able to cope with these harsh conditions, particularly the increased trigger and latency requirements at the HL-LHC. The lead tungstate crystals in the ECAL barrel sub-detector will still perform well. The avalanche photodiodes which detect the scintillation light will also continue to be operational with some increase in noise due to radiation-induced dark currents. However the entire readout electronics will need to be replaced. The upgraded detector will have a 25 fold improved trigger granularity and a sampling rate increase by a factor of four. In addition, the upgraded detector will have the new capability to provide precision timing measurements for photons and electrons with energies greater than 10 GeV. This will significantly improve the performance under the predicted pile-up conditions. High precision time resolution will be exploited for pileup mitigation and to permit the assignment of physics objects to their correct vertices. In this report the status of the ongoing R&D activities for the ECAL barrel upgrade will be presented.

Triton identification in the 6Li(n, t)4He reaction measurement with the grid ionization chamber at CSNS Back-n white neutron source

The measurement of 6Li(n, t)4He differential cross section is the first experiment conducted with the Light-charged Particle Detector Array (LPDA) at the Back-n white neutron source of the China Spallation Neutron Source. The LPDA system consists of three kinds of detectors. One of them is the grid ionization chamber (GIC), which has the capability of particle identification. The particle identification performance of the GIC is presented based on the data collected in this experiment. Signals from the anode and the cathode of the GIC are digitized through the readout electronics and DAQ system. The offline data analysis is performed in two major steps. The first step is the processing of the original signal waveform digitized by the readout electronics. A set of digital filter algorithms including RC-CR filter, band-pass filter and digital CFD are developed and implemented in the original signal processing in order to obtain a high signal-noise ratio and a precise timing resolution. The second step focuses on the identification of triton events. The triton identification efficiency is measured to be 98% using a multivariate analysis algorithm implemented in the TMVA package in ROOT to discriminate the triton events and background events. In general, the performance of the GIC has met the baseline requirement of the experiment measurement.