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Arrays of superconducting transition-edge sensor (TES) microcalorimeters are attractive for some X-ray experiments where the combination of higher collection efficiency than crystal spectrometers and much better energy resolution than semiconductor detectors is enabling. For hard X-ray (>2 keV) applications, a TES is often integrated with an extra absorber to extend its dynamic range, quantum efficiency and collecting area. For >100 keV applications, millimeter size absorbers have been manually attached to TES pixels after fabrication. At lower energies, the absorber size needs to be much smaller, because a large heat capacity degrades energy resolution. In that case, the absorber is directly electroplated or evaporated on the TES during the fabrication process. In this work, we present TES microcalorimeters optimized for the intermediate hard X-ray energy region (20 keV ∼ 100 keV) that have thick absorbers directly deposited during the TES fabrication process. This microcalorimeter is designed to measure high-resolution muonic atom transition X-ray spectra as a method to study quantum electrodynamics (QED) effects. The absorber is comprised of evaporated gold and electroplated bismuth layers and is designed to optimize dynamic range, collecting efficiency, and energy resolution in the 20 keV to 45 keV energy range. A prototype with pure gold absorbers has been fabricated and characterized, in order to obtain a first experimental reference in the detector development process. [ABSTRACT FROM AUTHOR]

The iron calorimeter (ICAL) detector at the India-based Neutrino Observatory (INO) will be used to measure neutrino mass hierarchy. The magnet in the ICAL detector will be used to distinguish the \mu ^- and \mu ^+ events induced by \nu \mu and anti- \nu \mu , respectively. Due to the importance of the magnet in ICAL, an electromagnetic simulation has been carried out to study the $B$ -field distribution in iron using various designs. The simulation shows better uniformity in the portion of the iron layer between the coils, which is bounded by regions that have lesser field strength as we move to the periphery of the iron layer. The ICAL magnet was configured to have a tiling structure that gave the minimum reluctance path, while keeping a reasonably uniform field pattern. This translates into less ampere-turns needed for generation of the required magnetic field. At low ampere-turns, a larger fractional area with $|B|\ge 1$ T can be obtained using a soft magnetic material. A study of the effect of the magnetic field on muon trajectories has been carried out using GEANT4. For muons up to 20 GeV, the energy resolution improves as the magnetic field increases from 1.1 to 1.8 T. The charge identification efficiency for muons was found to be >90% except for large zenith angles. [ABSTRACT FROM PUBLISHER]

The Mu2e experiment at Fermilab is designed to explore charged lepton flavor violation by searching for muon-to-electron conversion. The magnetic field generated by a system of solenoids is a crucial component of Mu2e and requires accurate characterization to detect any potential flaws and to produce a detailed field map. In order to design and build a precise field mapping system consisting of Hall and NMR probes, tolerances and precision for such a system need to be evaluated. To generate a final magnetic field map of the Mu2e solenoids, a continuous field has to be extracted from a discrete set of measurement points. A design for the Mu2e field mapping hardware, and results from simulations to specify parameters for Hall and NMR probes are presented. A fitting procedure for the analytical treatment of our expected magnetic measurements is introduced. [ABSTRACT FROM PUBLISHER]

The Mu2e experiment at Fermilab has been approved by the Department of Energy to proceed with the development of the preliminary design. Integral to the success of Mu2e is the superconducting solenoid system. One of the three major solenoids is the detector solenoid that houses the stopping target and the detectors. The goal of the detector solenoid team is to produce detailed design specifications that are sufficient for vendors to produce the final design drawings, tooling and fabrication procedures and proceed to production. In this paper we summarize the reference design of the detector solenoid. [ABSTRACT FROM PUBLISHER]

An intense muon beam is mandatory for next-generation experiments to search for lepton flavor violating processes in the muon sector. The COMET experiment, J-PARC E21, aims to search for muon to electron conversion with an unprecedented sensitivity. All the components of the experiment, such as the pion production target, the muon stopping target and the tracker are embedded in superconducting solenoids, resulting in a total length longer than 30 m. The pions are captured in a 5 T solenoid magnet with a diameter of 1.3 m, and decay to muons in the subsequent 3 T toroidal magnets over a length of 10 m. The pion capture solenoid is designed to be as small as possible, however, thick shielding is necessary within the solenoid to avoid severe radiation from the target. Aluminum-stabilized NbTi superconducting wire is employed to reduce the cold mass and energy deposited in it. The damage of the conductor of the coils should be estimated carefully, since the expected neutron fluence reaches 10^22\ neutrons/m^2. This paper describes the design of the solenoid magnets and R&D programs. [ABSTRACT FROM AUTHOR]