We report measurements of the transverse diffusion of electrons in P-10 gas (90% Ar, 10% CH4) in a laboratory-scale time projection chamber (TPC) utilizing a novel pixelated signal capture and digitization technique known as Q-Pix. The Q-Pix method incorporates a precision switched integrating transimpedance amplifier whose output is compared to a threshold voltage. Upon reaching the threshold, a comparator sends a 'reset' signal, initiating a discharge of the integrating capacitor. The time difference between successive resets is inversely proportional to the average current at the pixel in that time interval, and the number of resets is directly proportional to the total collected charge. We developed a 16-channel Q-Pix prototype fabricated from commercial off-the-shelf components and coupled them to 16 concentric annular anode electrodes to measure the spatial extent of the electron swarm that reaches the anode after drifting through the uniform field of the TPC. The swarm is produced at a gold photocathode using pulsed UV light. The measured transverse diffusion agrees with simulations in PyBoltz across a range of operating pressures (200-1500 Torr). These results demonstrate that a Q-Pix readout can successfully reconstruct the ionization topology in a TPC.

The high-luminosity upgrade to the LHC requires a new silicon-strip charged-particle tracking detector for ATLAS. The HCC (Hybrid Controller Chip) is one of three new radiation -tolerant ASICs for this silicon-strip detector. As the interface to multiple binary readout ASICs, the HCC is responsible for buffering and forwarding control signals and readout requests to them as well as serializing their readout data into a 640 Mbps output. All HCCs undergo a suite of tests to verify their analog and digital functionality. The yield for the HCC exceeds the 90% target for production.

The verification of ASICs through simulation is critical to ensure their successful operation in particle physics detectors and to minimize the number of long and expensive production cycles required. Three radiation-tolerant ASICs (HCC, AMAC, and ABC) will perform the front-end readout, monitoring, and control of the ITk Strip charged-particle tracker for the ATLAS detector at the HL-LHC. The Python-based cocotb verification framework is used to design sophisticated tests with contributions from ASIC verification non-experts and students. The verification program includes interactions between multiple ASICs, realistic data flows, operational stress tests, and a focus on mitigation of disruptive Single Event Effects due to radiation.

For the high-luminosity phase of the LHC, which begins operation in 2029, the current ATLAS inner detector will be replaced by a new tracker, the ITk. The ITk consists of two subdetectors, one using pixels and the second using silicon-strips, the ITk Strip detector. The HCC and AMAC chip are radiation-tolerant ASICs that contribute to the front-end readout, monitoring and control of the ITk Strip subsystem. Low temperature startups and low internal regulated voltage tests have been performed on HCC and AMAC to guarantee their reliability at edge operation conditions. In addition, to ensure the operation of the HCC and AMAC under a radiation heavy environment, gamma and x-ray irradiation campaigns were conducted. HCC and AMAC successfully operated at harsher conditions than the ones expected during the HL-LHC.

For the high-luminosity upgrade to the LHC, the ATLAS Inner Detector will be replaced by an all-silicon tracker (ITk) consisting of two systems: pixels and strips. HCC and AMAC are ITk Strip ASICs vital for performing the system readout, monitoring, and control. To ensure these ASICs will successfully operate in the high-radiation environment of the HL-LHC, they need to be tested for radiation tolerance, and tests have been performed using both heavy ions and protons. The ASIC designs were shown to protect against single event effects due to radiation.

The detection of neutrinos from core-collapse supernovae may reveal important process features as well as neutrino properties. The detection of supernova neutrinos is one of the main science drivers for future kiloton-scale neutrino detectors based on liquid argon. Here we show that for such detectors the intrinsically 3D readout in Q-Pix offers numerous advantages relative to a wire-based readout, such as higher reconstruction efficiency, lower energy threshold, considerably lower data rates, and potential pointing information.

The upgrades of ATLAS and CMS for the High Luminosity LHC (HL-LHC) highlighted physics objects timing as a tool to resolve primary interactions within a bunch crossing. Since the expected pile-up is around 200, with an r.m.s. time spread of 180 ps, a time resolution of about 30 ps is needed. The timing detectors will experience a 1-MeV neutron equivalent fluence of about Phi(eq) = 10(14) and 10(15) cm(-2) for the barrel and end-cap regions, respectively. In this contribution, deep diffused Avalanche Photo Diodes (APDs) produced by Radiation Monitoring Devices are examined as candidate timing detectors for HL-LHC applications. To improve the detector's timing performance, the APDs are used to directly detect the traversing particles, without a radiator medium where light is produced. Devices with an active area of 8 x 8 mm(2) were characterized in beam tests. The timing performance and signal properties were measured as a function of position on the detector using a beam telescope and a microchannel plate photomultiplier (MCP-PMT). Devices with an active area of 2 x 2 mm(2) were used to determine the effects of radiation damage and characterized using a ps pulsed laser. These detectors were irradiated with neutrons up to Phi(eq) = 10(15) cm(-2) .

The increased luminosity of the HL-LHC will require more channels in the upgraded ATLAS Tracker, as a result of the finer detector segmentation. Thus, an upgraded and more efficient HV biasing of the sensors will also be needed and is among the many technological challenges facing the ATLAS Tracker Upgrade. A number of approaches, including the sharing of the same HV line among several sensors and suitable HV switches, along with their control circuitry are currently being investigated for this purpose. The proposed solutions along with latest test results and measurements will be described.

We describe a dedicated high spatial resolution time-of-flight-capable breast PET scanner and its intrinsic performance. The PET scanner comprises of two detector heads, each composed of a 4×2 arrangement of PET detectors, and with each detector housing a 32 × 32 array of 1.5×1.5×15 mm 3 LYSO crystals. With a target TOF resolution <; 400 ps, we have developed a waveform sampling data acquisition system for the scanner. The data acquisition (DAQ) is modular and uses the DRS4 chip to perform waveform sampling at up to 5 Gsps. Performance evaluation demonstrates good crystal discrimination, energy resolution, and timing resolution of ~400 ps FWHM; indicating that the DAQ meets the needs of the TOF breast PET scanner.

Recent interest in pile-up mitigation through fast timing at the HL-LHC has focused attention on technologies that now achieve minimum ionising particle (MIP) time resolution of 30 picoseconds or less. The constraints of technical maturity and radiation tolerance narrowed the options in this rapidly developing field for the ATLAS and CMS upgrades to low gain avalanche detectors and silicon photomultipliers. In a variety of applications where occupancies and doses are lower, devices with pixel elements of order 1 cm(2), nevertheless achieving 30 ps, would be attractive. In this paper, deep diffused Avalanche Photo Diodes (APDs) are examined as candidate timing detectors for HL-LHC applications. Devices with an active area of 8 x 8 mm(2) are characterised using a pulsed infrared laser and, in some cases, high energy particle beams. The timing performance as well as the uniformity of response are examined. The effects of radiation damage on current, signal amplitude, noise, and timing of the APDs are evaluated using detectors with an active area of 2 x 2 mm(2). These detectors were irradiated with neutrons up to a 1-MeV neutrons fluence Phi(epsilon q) = 10(15) cm(-2). Their timing performance was characterised using a pulsed infrared laser. While a time resolution of 27 +/- 1 ps was obtained in a beam test using an 8 x 8 mm(2) sensor, the present study only demonstrates that gain loss can be compensated by increased detector bias up to fluences of Phi(epsilon q) = 6.10(13) cm(-2). So it possibly falls short of the Phi(epsilon q) = 10(14) cm(-2) requirement for the CMS barrel over the lifetime of the HL-LHC.

For their operation at the CERN High Luminosity Large Hadron Collider (HL-LHC), the ATLAS and CMS experiments are planning to implement dedicated systems to measure the time of arrival of minimum ionizing particles with an accuracy of about 30 ps. The timing detectors will be subjected to radiation levels corresponding up to a 1-MeV neutrons fluence (Φeq) of 1015 cm−2 for the goal integrated luminosity of HL-LHC of 3000 fb−1. In this paper, deep-diffused Avalanche Photo Diodes (APDs) produced by Radiation Monitoring Devices are examined as candidate timing detectors for HL-LHC applications. These APDs are operated at 1.8 kV, resulting in a gain of up to 500. The timing performance of the detectors is evaluated using a pulsed laser. The effects of radiation damage on current, signal amplitude, noise, and timing performance of the APDs are evaluated using detectors irradiated with neutrons up to Φeq = 1015 cm−2.

The dome of Santa Maria del Fiore, Florence Cathedral, was built between 1420 and 1436 by architect Filippo Brunelleschi and it is now cracking under its own weight. Engineering efforts are under way to model the dome's structure and reinforce it against further deterioration. According to some scholars, Brunelleschi might have built reinforcement structures into the dome itself; however, the only known reinforcement is a wood chain 7.75 m above the springing of the Cupola. Multiple scattering muon radiography is a non-destructive imaging method that can be used to image the interior of the dome's wall and therefore ascertain the layout and status of any iron substructure in it. A demonstration measurement was performed at the Los Alamos National Laboratory on a mock-up wall to show the feasibility of the work proposed, and a lightweight and modular imaging system is currently under construction. We will discuss here the results of the demonstration measurement and the potential of the proposed technique, describe the imaging system under construction and outline the plans for the measurement. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.

The ATLAS (one of two general purpose detectors at the LHC) Transition Radiation Tracker (TRT) is the outermost of the three tracking subsystems of the ATLAS Inner Detector. It is a large straw-based detector and contains about 350,000 electronics channels. The performance of the TRT as tracking and particularly particle identification detector strongly depends on stability of the operation parameters with most important parameter being the gas gain which must be kept constant across the detector volume. The gas gain in the straws can vary significantly with atmospheric pressure, temperature, and gas mixture composition changes. This paper presents a concept of the gas gain stabilisation in the TRT and describes in detail the Gas Gain Stabilisation System (GGSS) integrated into the Detector Control System (DCS). Operation stability of the GGSS during Run-1 is demonstrated.

The ATLAS experiment is a general purpose detector aiming to fully exploit the discovery potential of the Large Hadron Collider (LHC) at CERN. It is foreseen that after several years of successful data-taking, the LHC physics programme will be extended in the so-called High-Luminosity LHC, where the instantaneous luminosity will be increased up to 5 × 1034 cm−2 s−1. For ATLAS, an upgrade scenario will imply the complete replacement of its internal tracker, as the existing detector will not provide the required performance due to the cumulated radiation damage and the increase in the detector occupancy. The current baseline layout for the new ATLAS tracker is an all-silicon-based detector, with pixel sensors in the inner layers and silicon micro-strip detectors at intermediate and outer radii. The super-module is an integration concept proposed for the strip region of the future ATLAS tracker, where double-sided stereo silicon micro-strip modules are assembled into a low-mass local support structure. An electrical super-module prototype for eight double-sided strip modules has been constructed. The aim is to exercise the multi-module readout chain and to investigate the noise performance of such a system. In this paper, the main components of the current super-module prototype are described and its electrical performance is presented in detail.

Waveform sampling is an appealing technique for instruments requiring precision time and pulse-height measurements. Sampling each photomultiplier tube (PMT) waveform at oscilloscope-like rates of several gigasamples per second enables one to process PMT signals digitally, which in turn makes it straightforward to optimize timing resolution and amplitude (energy and position) resolution in response to calibration effects, pile-up effects, and other systematic sources of waveform variation. We describe a system design and preliminary implementation that neatly maps waveform-sampling technology onto the LaPET prototype whole-body time-of-flight PET scanner that serves as the platform for testing this new technology.

The possible physical mechanism of the anomalous recovery effect in SiGe bipolar transistors is described. The qualitative analysis of saturated oxide trapped charge and interface trap densities at very high total doses as a function of dose rate affords an explain of decreasing excess base current and increasing current gain during further low dose rate irradiation. (C) 2014 Elsevier Ltd. All rights reserved.

A detailed description of the integration structures for the barrel region of the silicon strips tracker of the ATLAS Phase-II upgrade for the upgrade of the Large Hadron Collider, the so-called High Luminosity LHC (HL-LHC), is presented. This paper focuses on one of the latest demonstrator prototypes recently assembled, with numerous unique features. It consists of a shortened, shield-less, and double sided stave, with two candidate power distributions implemented. Thermal and electrical performances of the prototype are presented, as well as a description of the assembly procedures and tools.

This paper discusses initial imaging results from a high-resolution time-of-flight detector specifically developed for a limited-angle dedicated breast PET scanner. To maintain high spatial-resolution and sensitivity, the detector design consists of 32 × 32 array of 1.5 × 1.5 × 15 mm3 LYSO crystals coupled to a single Hamamatsu H8500 multi-anode photomultiplier tube with a modified high-voltage divider circuit. To minimize the number of readout channels, compact front-end electronics that summed anode-signals along each of the orthogonal directions was also developed. Experimental performance evaluation of a complete detector-module demonstrates excellent energy, timing resolution and clear discrimination of most crystals. An average energy resolution of about 12.7% FWHM and an average coincidence timing resolution of 348 ps for two such detectors was measured. The dedicated breast PET scanner comprises of two parallel detector heads, each 15 cm by 10 cm and comprised of two rows of three detector-modules. We also experimentally evaluated the imaging capability of the scanner design via an experimental benchtop-demonstrator consisting of two fully assembled detector-modules on opposing translational stages. Imaging experiments with a hot lesion phantom that had an 8-mm diameter lesion with 8:1 activity uptake ratio, successfully demonstrate the capability of the system in imaging small lesions in a uniform background.