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Cosmic ray muon has strong penetrating power and no ionizing radiation hazards, which makes it an ideal probe for detecting special nuclear materials (SNMs). In this article, a high spatial resolution muon tomography system based on Micromegas detectors is proposed to optimize the imaging time and quality. The proposed system includes eight Micromegas detectors based on the thermal bonding technique and a scalable readout system. In addition, a multiplexing method based on position encoding is developed to reduce the number of electronics channels by order of magnitude. The spatial resolution of the proposed system with encoding readout can reach a value of hundred micrometers. Finally, a tomography test is performed, and test results show that this proposed system can image 2-cm objects and distinguish different materials. [ABSTRACT FROM AUTHOR]

We present a field-programmable gate array (FPGA)-based technique for the on-line identification of highly ionizing particles in a liquid xenon (LXe) detector. The method was developed and successfully exploited to select $\alpha $ particles emitted by 241Am sources submerged in LXe in an overwhelming, mostly beam-related, $\gamma $ -ray background. After revising the main features of xenon and other liquid noble gases as ultra-violet (UV) scintillating media, we describe the algorithm idea and its firmware implementation. We then present the results in terms of efficiency and background suppression for the real-time $\alpha $ -particle tagging and the limits of the MEG trigger configuration. Finally, we show that in MEG II we are going to overcome the main issues and further improve the performances. [ABSTRACT FROM AUTHOR]

The Mu2e experiment at the Fermilab Muon Campus will search for the coherent neutrinoless conversion of a muon into an electron in the field of an aluminum nucleus with a sensitivity improvement by a factor of 10 000 over existing limits. Such a charged lepton flavor-violating reaction probes new physics at a scale unavailable with direct searches at either present or planned high-energy colliders. The Mu2e Trigger and Data Acquisition (TDAQ) system exploits otsdaq as its online Data Acquisition System (DAQ) solution. Developed at Fermilab, otsdaq integrates both the artdaq DAQ and the art analysis frameworks for event transfer, filtering, and processing. otsdaq is an online DAQ software suite with a focus on flexibility and scalability and provides a multi-user, web-based, interface accessible through a web browser. The read out controllers (ROCs) stream out zero-suppressed data continuously from the detector subsystems to the data transfer controllers (DTCs). The data stream is then read over the peripheral component interconnect express (PCIe) bus to a software filter algorithm that selects events which are combined with the data flux coming from a cosmic-ray veto (CRV) system. The detector control system (DCS) has been developed using the experimental physics and industrial control system (EPICS) open source platform for monitoring, controlling, alarming, and archiving. The DCS has been integrated into otsdaq. A prototype of the TDAQ system and the DCS has been built at Fermilab’s Feynman Computing Center. In this article, we report on the progress of the integration of this prototype in the online otsdaq software. [ABSTRACT FROM AUTHOR]

J-PARC E16 is an experiment to examine the origin of hadron mass through a systematic measurement of spectral changes of vector mesons in nuclei. The measurement of $e^{+}e^{-}$ pairs from the decay of vector mesons will provide the information of the partial restoration of the chiral symmetry in a normal nuclear density. To resolve a pulse pile-up and achieve good discrimination of $e^{+}$ and $e^{-}$ from the background of a reaction rate of an order of 10 MHz, the data acquisition (DAQ) system uses waveform sampling chips of APV25 and DRS4. The trigger rate and data rate are expected to be 1 kHz and 120–330 MiB/s, respectively. The DAQ system for readout of APV25 and DRS4 were developed, where events were synchronized by common trigger and tag data. The first commissioning in beam, called Run-0a, was performed in June 2020 with about 1/4 of the designed setup. The DAQ worked with a trigger rate of 300 Hz in the Run-0a and the main bottleneck was a large data size of APV25. Further optimization of the DAQ system will improve the performance. [ABSTRACT FROM AUTHOR]

The CMS experiment at the LHC selects events with a two-level trigger system, the Level-1 (L1) trigger, and the high-level trigger (HLT). The HLT reduces the rate from 100 to about 1 kHz and has access to the full detector readout and runs a streamlined version of the offline event reconstruction. During LHC Run-2, the peak instantaneous luminosity reached values up to $2.0\times 10^{34}$ cm−2s−1, posing a challenge to the online event selection. An overview of the HLT system at CMS, the online physics object reconstruction, and the main triggers using those physics objects in 2016–2018 proton collision data-taking period is presented. The performance of a representative set of physics triggers is also discussed. [ABSTRACT FROM AUTHOR]

The COherent Muon to Electron Transition (COMET) experiment aims to search for the neutrinoless muon to electron transition process with new sensitivity levels. The online trigger system is an integral part of achieving the sensitivity levels required and will be subject to an expected neutron fluence of up to $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ within regions inside the detector solenoid. Consequently, a significant number of soft errors in the logic of the onboard field programmable gate arrays (FPGAs) can occur, requiring error correction for single event upsets and firmware reprogramming schemes for unrecoverable soft errors. We studied the radiation tolerance of the COMET Phase-I front-end trigger system, called COMET TRIgger (COTTRI), subject to neutron fluence on order $10^{12}\,\,n \cdot \mathrm {cm}^{-2}$ with multiple error correcting codes and automatic firmware reconfiguration. The regions measured were the configuration random access memory (RAM), block RAM (BRAM) and also in a multigigabit transfer link using copper cables that will be used for communication between different trigger boards during Phase-I. The resulting cross sections observed suggest the most significant impact to the experiment will come from unrecoverable soft errors in configuration RAM (CRAM), with dead time expected to be 4.2% ± 1.3%. The effect of multibit errors in BRAM was found to be almost negligible in COMET Phase-I. In addition, multiple solutions have already been proposed in order to suppress these errors further. Soft errors observed in the multigigabit transfer links were measured to be of two orders of magnitude less impact compared to the unrecoverable errors in CRAM. We concluded that the COTTRI system meets the trigger requirement in COMET Phase-I. [ABSTRACT FROM AUTHOR]

The Belle II experiment at the SuperKEKB collider at KEK, Tsukuba, Japan has successfully started taking data with the full detector in March 2019. Belle II is a luminosity frontier experiment of the new generation to search for physics beyond the Standard Model of elementary particles, from precision measurements of a huge number of $B$ and charm mesons and tau leptons. To read out the events at a high rate from the seven subdetectors of Belle II, we adopt a highly unified readout system, including a unified trigger-timing distribution system (TTD), a unified high-speed data link system (Belle2link), and a common backend system to receive Belle2link data. Each subdetector frontend readout system has a field-programmable gate array (FPGA) in which unified firmware components of the TTD receiver and Belle2link transmitter are embedded. The system is designed for data taking at a trigger rate up to 30 kHz with a dead-time fraction of about 1% in the frontend readout system. The trigger rate is still much lower than our design. However, the background level is already high because of the initial vacuum condition and other accelerator parameters, and it is the most limiting factor of the accelerator and detector operation. Hence, the occupancy and radiation effects to the frontend electronics are rather severe, and they cause various kinds of instabilities. We present the performance of the system, including the achieved trigger rate, dead-time fraction, and stability, and discuss the experience gained during the operation. [ABSTRACT FROM AUTHOR]

Ground-level cosmic ray muon detections have various potential applications in the predictions of space and Earth weather variations and muon tomography. However, in order to push its practical applications, a low-power, low-cost, high-accuracy, and portable ground-level cosmic ray muon detection system needs to be developed. In this article, we present a high time-resolution and low-power readout integrated circuit (ROIC) for portable ground-level cosmic ray muon detection. The ROIC comprises preamplifiers, comparators, encoding modules, a delay-locked loop (DLL), and a data transfer module. The preamplifiers amplify the weak signals produced by the muon detector. The comparators convert the amplified signals into digital signals. The encoding modules extract and store the time information of the input pulses produced by the comparator, and the data transfer module transmits them to a microcontroller unit (MCU). A pulse edge detecting method using DLL clocks is employed to improve the time-resolution and limit the power consumption of the ROIC. A 32-channel prototype of the ROIC was designed and fabricated in a 0.18- $\mu \text{m}$ mixed-signal CMOS process. The main chip size is 11.4 mm2. A one-channel double-layer plastic scintillator muon detector was used to test the performance of the ROIC. A time-resolution of 1.0 ns was achieved with a system clock of 50 MHz, and the ROIC power consumption was measured at 1.9 mW/channel. Compared with existing muon readout electronics systems, the system using the proposed ROIC achieves high time-resolution and accuracy, with low power consumption and a smaller size, making it suitable for portable real-time cosmic ray muon detection. [ABSTRACT FROM AUTHOR]

The large Hadron collider (LHC) is expected to increase its center-of-mass energy from 13 to 14 TeV for Run 3 scheduled from 2022 to 2024. After Run 3, upgrades for the high-luminosity-LHC (HL-LHC) program are planned and the operation will start in 2027, increasing the instantaneous luminosity to 5.0–7.5 times its nominal luminosity. Continuous upgrades of the ATLAS trigger system are planned to cope with the high event rate and to keep the physics acceptance. During the long shutdown period before Run 3, new detectors will be installed to improve the trigger performance. A new trigger logic, combining information from detectors located outside of the magnetic field and new detectors installed inside the magnetic field, will be introduced for Run 3 to reduce the trigger rate. In order to handle data from the various detectors, a new trigger processor board has been developed and the design is presented. During the upgrade for HL-LHC, the trigger and readout systems of the first level hardware-based part are planned to be upgraded. Full-granularity information will be transferred to the trigger processor board which enables more OFF-line like track reconstruction in the hardware-based system. To handle the full-granularity information and perform the hardware-based track reconstruction, the trigger processor board will be equipped with a field programmable gate array (FPGA) with hundreds of transceivers and a large memory. Expected performance for the hardware-based endcap muon trigger in Run 3 and HL-LHC will also be presented. [ABSTRACT FROM AUTHOR]

The Mu3e experiment aims to find or exclude the lepton flavor violating decay μ+ → e+e−e+$ with a sensitivity of one in 1016 muon decays. The first phase of the experiment is currently under construction at the Paul Scherrer Institute (PSI, Switzerland), where beams with up to 108 muons per second are available. The detector will consist of an ultra-thin pixel tracker made from High-Voltage Monolithic Active Pixel Sensors (HV-MAPS), complemented by scintillating tiles and fibers for precise timing measurements. The experiment produces about 100Gbit/s of zero-suppressed data, which are transported to a filter farm using a network of field programmable gate arrays (FPGAs) and fast optical links. On the filter farm, tracks and three-particle vertices are reconstructed using highly parallel algorithms running on graphics processing units, leading to a reduction of the data to 100 Mbyte/s for mass storage and offline analysis. This article introduces the system design and hardware implementation of the Mu3e data acquisition and filter farm. [ABSTRACT FROM AUTHOR]