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Optical imaging of muon beams is a promising method for range estimations. However, our previous optical imaging method could only measure 2-D projection images. To measure the beam ranges and widths at any position of the muon beam, 3-D beam images are desired. For this purpose, we developed an optical imaging system using a silver-activated zinc sulfide (ZnS(Ag)) sheet combined with a mirror and a cooled charge-coupled device (CCD) camera. The ZnS(Ag) sheet was set in a black box and irradiated by a positive muon beam at the Japan Proton Accelerator Research Complex (J-PARC). Acrylic plates were used to absorb the muon beam. The measured optical images with different thicknesses of the acrylic plates were stacked and interpolated to create a 3-D optical image, and then the depth and lateral profiles were evaluated. From the depth profile derived from the 3-D image, the Bragg peak position could be estimated. The lateral profiles at the Bragg peak positions could also be derived. We confirmed that 3-D optical imaging was possible using the developed system with a ZnS(Ag) sheet. The system is promising for measuring muon beam distribution, conducting research on muons, and developing future muon radiotherapy. [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]

Negative and positive muon-induced single-event upsets (SEUs) are studied in 20-nm bulk planar SRAMs. Muon irradiation is performed using a mono-energetic source with varying the muon energy. The energy dependence of the cross sections (CSs) of SEUs and multiple-cell upsets (MCUs) shows the significant contribution of muon capture reactions for the negative muon, as reported in previous studies. Interestingly, MCU events are found for the positive muon, in contrast to the previous studies. The CSs for the negative and positive muons are compared with that for the other terrestrial radiations: high-energy neutrons, thermal neutrons, and alpha particles. The voltage dependence of the SEU CS, together with the empirical model for charge collection, demonstrates the difference in the contributing secondary ions among the negative muon, the high-energy neutron, and the thermal neutron. The MCU events are thoroughly analyzed in terms of their ratio to the total events and their fail bit patterns. The results reveal that the MCU characteristics for the negative muon are different from that for the other terrestrial radiations due to the muon capture reactions, where parasitic bipolar effects and the isotropic emission of secondary ions are important factors. [ABSTRACT FROM AUTHOR]

Neutrons with energies between 0.1 and 10 MeV can significantly impact the soft error rate (SER) in SRAMs manufactured in scaled technologies, with respect to high-energy neutrons. Their contribution is evaluated in accelerator, ground-level, and avionic (12 km of altitude) environments. Experimental cross sections were measured with monoenergetic neutrons from 144 keV to 17 MeV, and the results benchmarked with Monte Carlo simulations. It was found that even 144 keV neutrons can induce upsets due to elastic scattering. Moreover, neutrons in the 0.1–10 MeV energy range can induce more than 60% of the overall upset rate in accelerator applications, while their contribution can exceed 18% in avionics. The SER due to neutrons below 3 MeV, whose contribution has always been considered negligible, is found to be up to 44% of the total upsets in accelerator environments. These results have strong radiation hardness assurance (RHA) implications for those environments with high fluxes of neutrons in the 0.1–10 MeV energy range. [ABSTRACT FROM AUTHOR]

The pion resonance in the nuclear reaction cross section is seen to have a direct impact on the single-event effect (SEE) cross section of modern electronic devices. This was experimentally observed for single-event upsets and single-event latchup. Rectangular parallelepiped (RPP) models built to fit proton data confirm the existence of the pion SEE cross-section resonance. The impact on current radiation hardness assurance (RHA) soft error rate (SER) predictions is, however, minimal for the accelerator environment since this is dominated by high neutron fluxes. The resonance is not seen to have a major impact on the high-energy hadron equivalence approximation established for testing in mixed-field facilities. [ABSTRACT FROM AUTHOR]

Negative and positive muon irradiation tests of static random access memories (SRAMs) were performed at Muon Science Innovation Channel (MuSIC) of Research Center for Nuclear Physics (RCNP), Osaka University. The muon-induced single event upset (SEU) cross sections for 65-nm bulk SRAMs were measured. The SRAM device was irradiated by the muon beams with average momenta ranging from 37.8 to 41.0 MeV/c at the beam exit. The incident muon fluence was measured using a one-by-one muon detection system with a plastic scintillator by taking advantage of the direct current (dc) muon beam and reliable absolute values of SEU cross sections were obtained. In addition to the measurement of the SEU cross sections, we measured muonic X-rays from the irradiated device to investigate the relation between the measured SEU cross section and the emission rate of muonic X-rays associated with the stopping position of the muons as a function of incident muon momentum. The result suggested that negative muons have a significant effect on SEUs by the emission of secondary light ions via negative muon capture reaction when negative muons stop near sensitive volumes (SVs) in SRAMs. [ABSTRACT FROM AUTHOR]

The planned upgrade of the A Large Ion Collider Experiment (ALICE) inner tracking system (ITS) aims at improving the ALICE performance in terms of spatial resolution and data rate readout. The new ITS will be a low-material-budget, high-granularity detector. It comprises seven concentric layers of monolithic active pixel sensors (MAPS), called ALPIDE, which are based on the TowerJazz 180-nm CMOS technology. In this article, we report on detection performance and radiation hardness studies of ALPIDE sensors. We show that these sensors keep having high detection efficiency for minimum ionizing particles (MIPs) (>99%) and low fake-hit rate while being radiation hard to some ${ 1.7} \times { 10}^{ 13}\,\,1$ MeV $\text{n}_{\text {eq}}$ cm−2 of nonionizing energy loss (NIEL) and 2.7 Mrad of total ionization dose (TID), which exceeds the expected radiation load during the detector lifetime ten times. ALPIDE sensors thus completely fulfill the design requirements. In addition, we show that measured cluster shape frequencies obtained at different operating points (thresholds, bias voltages) are well described with the state-of-the-art ALICE Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

Multiple-cell upset (MCU) in static random access memory (SRAM) is a major concern in radiation effects on very large scale integration (VLSI) since it can spoil error correcting codes (ECCs). Neutron-induced MCUs have been characterized for terrestrial environment. On the other hand, negative muon-induced MCUs, which are caused by secondary ions generated through muon capture process, were recently reported. Neutron- and negative muon-induced MCUs are both caused by secondary ions, and hence, they are expected to have some similarity. In this paper, we compare negative muon- and neutron-induced MCUs in 65-nm bulk SRAMs at the irradiation experiments using spallation and quasi-monoenergetic neutrons and monoenergetic negative muons. The measurement results show that the dependencies of MCU event cross section on operating voltage are almost identical. The high operating voltage makes both negative muon- and neutron-induced MCU cross sections larger due to parasitic bipolar action. Consequently, large-bit MCUs are observed under the irradiation using both neutrons and muons. On the other hand, at 0.4 V, neutrons induce larger-bit MCUs (> 12 bits) whereas negative muons cause up to 11-bit MCUs. Upsets of 3 or larger bits along word line (WL) are observed at spallation neutron beams. To explain the similarity of MCUs induced by neutrons and negative muons, the Monte Carlo simulation is conducted to investigate the deposited charge. The distributions of deposited charge obtained by the simulation are consistent with the above-mentioned experimental observations. [ABSTRACT FROM AUTHOR]

The Mu2e experiment at Fermilab searches for the charged-lepton flavor violating (CLFV) conversion of a negative muon into an electron in the field of an aluminum nucleus, with a distinctive signature of a monoenergetic electron of energy slightly below the muon rest mass (104.967 MeV). The Mu2e goal is to improve by four orders of magnitude the search sensitivity with respect to the previous experiments. Any observation of a CLFV signal will be a clear indication of new physics. The Mu2e detector is composed of a tracker, an electromagnetic calorimeter, and an external veto for cosmic rays surrounding the solenoid. The calorimeter plays an important role in providing particle identification capabilities, a fast online trigger filter, a seed for track reconstruction while working in vacuum, in the presence of 1-T axial magnetic field and in a harsh radiation environment. The calorimeter requirements are to provide a large acceptance for 100-MeV electrons and reach at these energies: 1) a time resolution better than 0.5 ns; 2) an energy resolution <10%; and 3) a position resolution of 1 cm. The calorimeter design consists of two disks, each one made of 674-undoped cesium iodine crystals read by two large area arrays of UV-extended silicon photomultipliers (SiPMs). We report here the construction and the test of the Module-0 prototype. The Module-0 has been exposed to an electron beam in the energy range around 100 MeV at the Beam Test Facility in Frascati. Preliminary results of timing and energy resolution at normal incidence are shown. A discussion of the technical aspects of the calorimeter engineering is also reported in this paper. [ABSTRACT FROM AUTHOR]

We are developing a new technique to apply transition-edge sensors (TESs) to X-ray spectroscopy of exotic atoms, especially of kaonic atoms. To demonstrate the feasibility of this pioneering project, performance of a TES-based X-ray detector was evaluated in pion- and kaon-beam environments at particle accelerators. We successfully observed X-rays from pionic-carbon atoms with a resolution as good as 7 eV FWHM at 6 keV. Also at a kaon beamline, we confirmed that the TES spectrometer will be able to achieve our resolution goal, 6 eV, in our first scientific campaign to measure X-rays from kaonic-helium atoms. [ABSTRACT FROM AUTHOR]

The performances of the OFFSET3 tracker (Optical Fiber Folded Scintillating Extended Tracker) are presented. It exploits a novel system for particle tracking, designed to achieve real-time particle imaging and tracking, large detection areas, and a high spatial resolution especially suitable for applications in medical diagnostics. The tracker is composed by two 288 \times 288~\mm^2 FOV position detectors stacked by 10 cm, made by 500 micron square scintillating fiber ribbons for both directions. The track position information is extracted in real-time in an innovative way, using a reduced number of readout channels, by means of which it is possible to obtain the large detection area with moderate cost and complexity. The architecture has been patented by the Istituto Nazionale di Fisica Nucleare (INFN). The performances of the tracker were investigated by beta sources, cosmic rays, 60 MeV-250 MeV proton and 400 MeV/A carbon clinical beams. [ABSTRACT FROM PUBLISHER]

CERN hosts a large number of electronic devices and equipment, functioning over its different particle accelerators. In certain areas, they operate in harsh radiation environments. In order to assure their proper functionality, the equipment or some of their sensitive components undergo several tests in experimental test areas representative of the LHC radiation fields, while specialized monitors constantly record the respective radiation levels. The purpose of this study is to evaluate the use of monitors using recent technology nodes (90 nm) in order to have a better estimation of the expected error rate of the devices. The H4IRRAD experimental test area has been specifically designed to reproduce the radiation field that is present within the LHC tunnel and shielded areas. It has been used to test our custom SRAM based monitors. The monitors have been exposed to a maximum dose and high energy hadron fluence of about 76 Gy and 1.3x10^11~\cm^-2 respectively. The results show that the total ionizing dose (TID) effect does not impact the bit cross section of our devices. Moreover the Single Event occurrence is coherent to the beam intensity fluctuations, proving that these devices are appropriate for SEU monitoring under mixed particle fields. [ABSTRACT FROM PUBLISHER]

Single Event Upset (SEU) measurements were performed using the European Space Agency's (ESA) Standard SEU Monitor in the H4 Irradiation mixed-field test area at CERN. The results, tightly correlated with the radiation environment, are compared with those obtained with the CERN Radiation Monitors (RadMons) as well as with the Monte Carlo simulation of the experimental setup using the FLUKA Monte Carlo transport code. In addition, the SEU cross section of the device for particles and energies not available in standard testing (such as charged pions or GeV-energy hadrons) are simulated and discussed, showing an increase of over a factor 2 for nucleons in the 200 MeV–3 GeV range. A monoenergetic SEU cross section measurement at 120 GeV is included in the analysis. [ABSTRACT FROM AUTHOR]

The construction of the 1st phase Japan Proton Accelerator Research Complex (J-PARC) was completed. Three major experimental facilities, which have been utilized by users, are instrumented with the superconducting magnet systems; a muon transport solenoid in Materials and Life Science Experimental Facility, a superconducting spectrometer in Hadron Experimental Facility, and a 150 m superconducting beam line in Neutrino Experimental Facility. There are also several superconducting magnet systems proposed as part of future experiments at J-PARC. The paper briefly summarizes the current status of the superconducting magnet systems currently in operation, and introduces the superconducting magnet systems associated with the new proposals. [ABSTRACT FROM AUTHOR]

A 3-GeV (333 \muA, 1.0 MW) proton beam from the J-PARC Rapid Cycle Synchrotron passes through a graphite target producing muons in the Materials and Life Science Facility. Muons of various momenta of up to 50 MeV/c and of both electric charges are captured and transported to an experimental area by using an axial magnetic field in the bore of solenoid magnets. This beam line, named Super Omega, is composed of a normal conducting MIC (Mineral Insulation Cable) magnet for capture, a curved superconducting solenoid system for transportation, and an axial focusing magnet system. Once in the experimental area, the muon beam is focused onto an experimental target for various purposes. The superconducting solenoid system is composed of one 6-m long straight section and two 45-degree segmented curved sections at both ends of the straight section. A magnetic field of about 2 T is applied in the transportation channel of 300 mm in diameter. The conceptual design of this solenoid system is reported. [ABSTRACT FROM AUTHOR]

The new muon beamline, MuSIC, is being constructed at the Research Center for Nuclear Physics (RCNP) at Osaka University in Japan. The project utilizes superconducting solenoid magnets to collect pions and to transport muons with the ultimate efficiency by putting pion-production target inside the solenoid magnet. This is the first of such a novel method to produce intense muon beams. All the superconducting coils are cooled with conduction cooling using Gifford-McMahon cryocoolers. A large superconducting coil with the diameter of 90 cm encloses the pion-production target and thick shielding to protect the coil against severe radiation from the target, so that energy deposit by particles on the coil should be less than 1 W. Pions are captured in a 3.5 T magnetic field and are injected into the subsequent toroidal magnets with the magnetic field of 2 T. Superconducting dipole coils are equipped on each solenoid coil of the transport solenoid to correct the particle trajectory in the toroidal field. The design and construction status of the solenoid channel are described in this paper. [ABSTRACT FROM AUTHOR]