High-Energy Proton Testing of Sensitive Electronics for use on Modular Infrared Molecules and Ices Sensor (MIRMIS) Instrument

The Comet Interceptor (CI) mission is ESA\u27s first F class mission, selected in June 2019. This mission consists of three spacecraft: Spacecraft A (main spacecraft), Spacecraft B1 (supplied by the Japanese space agency JAXA), and Spacecraft B2. In this paper, we highlight the Modular Infrared Molecular and Ices Sensor (MIRMIS) instrument, which is integrated into the CI Spacecraft A\u27s scientific payload. In addition to hardware contributions from Finland (VTT Finland) and the UK (University of Oxford), the MIRMIS instrument team includes members from the University of Helsinki and NASA\u27s Goddard Space Flight Centre. MIRMIS covers the spectral range of 0.9 to ~25 μm. This paper presents the preliminary high-proton-energy radiation test results of MIRMIS’ near-infrared detector arraysensitive electronic components. Proton beam testing is performed to estimate Single Event Effects (SEE) on the PCB boards and SEE and Total Non-Ionizing Dose (TNID)/ Displacement Damage (DD) on the detectors. The tests were conducted at the Paul Scherrer Institute (PSI) Proton Irradiation Facility (PIF), Villigen, Switzerland. The levels for the tests were based on the mission requirements for the ESA Comet Interceptor mission: 3 years (at 1 AU- Segment 1) and 2 years (at 0.9 AU- Segment 2). The DD levels from the analysis were equivalent to 1e11 protons/cm2 with an energy of 50 MeV. The electronics are exposed to high-energy protons causing Single Event Effects (SEE) which may induce potentially destructive and non-destructive effects. The test items primarily included the InGaAs image sensors (SCD Cardinal640, standard and low noise), Xilinx Spartan-6 FPGAs (Field Programmable Gate Arrays), and other proximity electronics. The proton energies were varied from 50 to 200 MeV, at fluxes of 106 to 108 particles/cm2/s. No events were observed on the standard Cardinal640 sensor at target fluences between 1.00E+10 to 1.00E+11 particles/cm2. FPGAs did not show any susceptibility to TNID at fluences up to 1.00E+11 (particles/cm2)

Time-of-flight spectroscopy of ultracold neutrons at the PSI UCN source

The ultracold neutron (UCN) source at the Paul Scherrer Institute (PSI) provides high intensities of storable neutrons for fundamental physics experiments. The neutron velocity spectrum parallel to the beamline axis was determined by time-of-flight spectroscopy using a neutron chopper. In particular, the temporal evolution of the spectrum during neutron production and UCN storage in the source storage volume was investigated and compared to Monte Carlo simulation results. A softening of the measured spectrum from a mean velocity of 7.7(1) m s$^{-1}$ to 5.1(1) m s$^{-1}$ occurred within the first 30 s after the proton beam pulse had impinged on the spallation target. A spectral hardening was observed over longer time scales of one measurement day, consistent with the effect of surface degradation of the solid deuterium moderator

Characterization of ultracold neutron production in thin solid deuterium films at the PSI UCN source

We determined the ultracold neutron (UCN) production rate by superthermal conversion in the solid deuterium (sD$_2$) moderator of the UCN source at the Paul Scherrer Institute (PSI). In particular, we considered low amounts of less than $20\,$mol of D$_2$, deposited on the cooled moderator vessel surfaces in thin films of a few mm thickness. We measured the isotopic ($c_\text{HD} < 0.2 \, \%$) and isomeric ($c_\text{para} \le 2.7 \, \%$) purity of the deuterium to conclude that absorption and up-scattering at $5\,$K have a negligible effect on the UCN yield from the thin films. We compared the calculated UCN yield based on the previously measured thermal neutron flux from the heavy water thermal moderator with measurements of the UCN count rates at the beamports. We confirmed our results and thus demonstrate an absolute characterization of the UCN production and transport in the source by simulations

Minimizing plasma temperature for antimatter mixing experiments

The ASACUSA collaboration produces a beam of antihydrogen atoms by mixing pure positron and antiproton plasmas in a strong magnetic field with a double cusp geometry. The positrons cool via cyclotron radiation inside the cryogenic trap. Low positron temperature is essential for increasing the fraction of antihydrogen atoms which reach the ground state prior to exiting the trap. Many experimental groups observe that such plasmas reach equilibrium at a temperature well above the temperature of the surrounding electrodes. This problem is typically attributed to electronic noise and plasma expansion, which heat the plasma. The present work reports anomalous heating far beyond what can be attributed to those two sources. The heating seems to be a result of the axially open trap geometry, which couples the plasma to the external (300 K) environment via microwave radiation

Search for an interaction mediated by axion-like particles with ultracold neutrons at the PSI

We report on a search for a new, short-range, spin-dependent interaction using a modified version of the experimental apparatus used to measure the permanent neutron electric dipole moment at the Paul Scherrer Institute. This interaction, which could be mediated by axion-like particles, concerned the unpolarized nucleons (protons and neutrons) near the material surfaces of the apparatus and polarized ultracold neutrons stored in vacuum. The dominant systematic uncertainty resulting from magnetic-field gradients was controlled to an unprecedented level of approximately 4 pT/cm using an array of optically-pumped cesium vapor magnetometers and magnetic-field maps independently recorded using a dedicated measurement device. No signature of a theoretically predicted new interaction was found, and we set a new limit on the product of the scalar and the pseudoscalar couplings $g_sg_p\lambda^2 < 8.3 \times 10^{-28}\,\text{m}^2$ (95% C.L.) in a range of $5\,\mu\text{m} < \lambda < 25\,\text{mm}$ for the monopole-dipole interaction. This new result confirms and improves our previous limit by a factor of 2.7 and provides the current tightest limit obtained with free neutrons

Association of concurrent acid-suppression therapy with survival outcomes and adverse event incidence in oncology patients receiving erlotinib

PURPOSE: Acid-suppression therapy is known to decrease the systemic exposure of erlotinib. The erlotinib prescribing information also recommends staggering dosing with a histamine-2 receptor antagonist (H(2)RA) and avoiding concurrent use of a proton-pump inhibitor (PPI). This retrospective analysis evaluated the frequency of concurrent acid-suppression therapy in oncology patients receiving erlotinib and its association with outcomes. METHODS: All patients prescribed erlotinib within UC San Diego Health System between February 26, 2011 and February 28, 2014 were assessed for eligibility, and for survival outcomes and adverse events. RESULTS: Of the 76 patients in the analysis, 24 were prescribed both a PPI and an H(2)RA with erlotinib therapy (31.6%). The two patient groups, with (n=24) and without PPI/H(2)RA (n=52), were similar in clinical characteristics and erlotinib dose. One patient received an H(2)RA therapy alone and was excluded from the analysis; no one received PPI therapy alone. Patients receiving erlotinib alone had a longer median progression-free survival (PFS) compared to patients with concurrent PPI/H(2)RA therapy (11.0 months vs. 5.3 months; P=0.029). Overall survival (OS) and incidence of rash and/or diarrhea did not correlate with use of acid-suppression therapy. CONCLUSION: Nearly one-third of subjects received acid-suppression therapy. Patients treated with erlotinib and PPI/H(2)RA therapy had shorter PFS, but similar OS and adverse event profile compared to those who did not receive acid-suppression

A large ‘Active Magnetic Shield’ for a high-precision experiment: nEDM collaboration

We present a novel Active Magnetic Shield (AMS), designed and implemented for the n2EDM experiment at the Paul Scherrer Institute. The experiment will perform a high-sensitivity search for the electric dipole moment of the neutron. Magnetic-field stability and control is of key importance for n2EDM. A large, cubic, 5 m side length, magnetically shielded room (MSR) provides a passive, quasi-static shielding-factor of about 10⁵ for its inner sensitive volume. The AMS consists of a system of eight complex, feedback-controlled compensation coils constructed on an irregular grid spanned on a volume of less than 1000 m³ around the MSR. The AMS is designed to provide a stable and uniform magnetic-field environment around the MSR, while being reasonably compact. The system can compensate static and variable magnetic fields up to ± 50 μT/m (homogeneous components) and ±5 μT/m (first-order gradients), suppressing them to a few μT in the sub-Hertz frequency range. The presented design concept and implementation of the AMS fulfills the requirements of the n2EDM experiment and can be useful for other applications, where magnetically silent environments are important and spatial constraints inhibit simpler geometrical solutions.ISSN:1434-6044ISSN:1434-605

Cyclotron cooling to cryogenic temperature in a Penning-Malmberg trap with a large solid angle acceptance

Magnetized nonneutral plasma composed of electrons or positrons couples to the local microwave environment via cyclotron radiation. The equilibrium plasma temperature depends on the microwave energy density near the cyclotron frequency. Fine copper meshes and cryogenic microwave absorbing material were used to lower the effective temperature of the radiation environment in ASACUSA's Cusp trap, resulting in significantly reduced plasma temperature

Reducing the background temperature for cyclotron cooling in a cryogenic Penning-Malmberg trap

Magnetized nonneutral plasma composed of electrons or positrons couples to the local microwave environment via cyclotron radiation. The equilibrium plasma temperature depends on the microwave energy density near the cyclotron frequency. Fine copper meshes and cryogenic microwave absorbing material were used to lower the effective temperature of the radiation environment in ASACUSA's Cusp trap, resulting in significantly reduced plasma temperature. (C) 2022 Author(s).All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY)license (http://creativecommons.org/licenses/by/4.0/)