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A high homogeneity superconducting magnet with conduction cooling is fabricated to calibrate Hall sensors for measuring mag-netic field in high energy particle accelerators. The magnet uses a single 1.5 W@4.2 K refrigerator. It combines indirect conduction of heat pipe and direct contact conduction to cool the magnet. The winding process of magnet are introduced and the magnetic field deviation is analyzed according to the manufacturing error. The excitation test and uniformity test are carried out and analyzed. The test results show that the uniformity does not exceed 20 ppm @ ϕ10 mm × 10 mm.

Feynman integral computations in theoretical high energy particle physics frequently involve square roots in the kinematic variables. Physicists often want to solve Feynman integrals in terms of multiple polylogarithms. One way to obtain a solution in terms of these functions is to rationalize all occurring square roots by a suitable variable change. In this paper, we give a rigorous definition of rationalizability for square roots of ratios of polynomials. We show that the problem of deciding whether a single square root is rationalizable can be reformulated in geometrical terms. Using this approach, we give easy criteria to decide rationalizability in most cases of square roots in one and two variables. We also give partial results and strategies to prove or disprove rationalizability of sets of square roots. We apply the results to many examples from actual computations in high energy particle physics.

The i-pipe system is a peculiar structural health monitoring system, based on Fiber Bragg Grating technology, installed on the central beam pipe of the compact Muon solenoid (CMS) experiment at CERN. In this contribution, i-pipe temperature sensors, originally conceived as thermal compensator for the strain sensors, are employed to monitor central beam pipe thermal behavior in correlation with the parameters of the particle beam travelling inside, in order to directly measure possible Beam RF induced heating effect. The i-pipe system turned out to be capable of monitoring, directly and without interference, the parameters of the particle beam circulating in the LHC ring. Hence, the results presented in this work pave the way to the use of the i-pipe as monitoring system of an accelerated high energy particle beam.

Space weather is driven and modulated by the activity in the Sun. Space weather events have the potential to inflict critical damage to space systems. Nowadays, space assets are essential in our basic needs, such as communications, cell phone networks, navigation systems, television and internet. Hence, understanding space weather dynamics and its effects on spacecraft is crucial for satellites engineers and satellite operators, in order to prevent and mitigate its impacts. In the last decade our Sun has erupted several times causing dozens of space weather events. Some of these led to satellite malfunctions and outages lasting from mere hours, up to days and weeks. This research is focused on two different space weather events, March 7–8, 2012, and September 6–10, 2017, that occurred during the last ten years and caused satellite anomalies that are related to an increase in the single event upsets rate. Single event upset is a bit flip in a memory device due to high energy particle interaction with the device sensitive volume. During these two periods, Eros B, a low Earth orbiting polar satellite detected an increased rate of single event upsets on two of its processing computers when the high energy proton flux was elevated. On both occasions X-class flares were detected, and the increased single event upsets count rate in Eros B took place only after the 100 MeV protons flux was three orders of magnitude above the background levels. In this research, Israeli satellite anomalies that were detected are first demonstrated.

Highly reliable Monte-Carlo event generators and detector simulation programs are important for the precision measurement in the high energy physics. Huge amounts of computing resources are required to produce a sufficient number of simulated events. Moreover, simulation parameters have to be fine-tuned to reproduce situations in the high energy particle interactions which is not trivial in some phase spaces in physics interests. In this paper, we suggest a new method based on the Wasserstein Generative Adversarial Network (WGAN) that can learn the probability distribution of the real data. Our method is capable of event generation at a very short computing time compared to the traditional MC generators. The trained WGAN is able to reproduce the shape of the real data with high fidelity., Comment: To appear in Journal of the Korean Physical Society

Three high energy particle monitors (HPMs) employed onboard the Hard X-ray Modulation Telescope Insight-HXMT) can detect the charged particles from South Atlantic Anomaly (SAA) and hence provide the alert trigger for switch-on/off of the main detectors. Here a typical design of HPM with high stability and reliability is adopted by taking a plastic scintillator coupled with a small photomultiplier tube (PMT). The window threshold of HPM is designed as 1 MeV and 20 MeV for the incident electron and proton, respectively. Before the launch of Insight-HXMT, we performed in details the ground calibration of HPM. The measured energy response and its dependence on temperature are taken as essential input of Geant4 simulation for estimating the HPM count rate given with an incident particle energy spectrum. This serves as a guidance for choosing a reasonable working range of the PMT high voltage once the real SAA count rate is measured by HPM in orbit. So far the three HPMs have been working in orbit for more than two years. Apart from providing reliable alert trigger, the HPMs data are used as well to map the SAA region., Comment: 7 pages,15 figures

The Van Allen radiation belts consist of megaelectron volt particles trapped in the Earth’s magnetic field mainly with protons at low altitudes and electrons at high altitudes. These concentric, donut-shaped radiation belts are constantly changing due to a variety of physical processes caused by specific types of heliospheric structure. The radiation poses risks for astronauts and spacecraft systems. The understanding of these processes that operate across the universe can help with designs of future space missions as well as the understanding of the universe. The data gathered from the last three months of the Radiation Belt Storm Probes mission (RBSP mission) is examined for patterns and trends in the dynamics of the radiation belts and their relationships with solar activities. From the data, it is shown that the patterns of the high-energy particle dynamics in the belts follow the changes in solar activity. When the Sun’s magnetic field weakens, cosmic rays from deep space are able to carry an increased flux of energetic particles into the solar system. The outer belt exhibits a pattern of electron energization during cycles lasting an average of 27 days, corresponding to the time taken for one solar rotation. The sudden outward shift of the belts on July 19th, 2019 was most likely caused by the shutdown of one of the two Van Allen probes, as the relative position of the probe to the belts changed. Two solar wind streams that arrived from August 27th to the 28th caused the “dropout” event on August 28th, as the contact between the solar wind streams and magnetosphere pushed the magnetosphere’s boundary and enabled the particles outside the shifted boundary to escape into space. A positive polarity coronal hole high speed stream (CH HSS) contributed to the intense September electron re-energization process in the radiation belts starting on September 1st.

The mission CSES (China Seismo-Electromagnetic Satellite) will put into orbit satellites to study perturbations in the ionosphere, possibly correlated with the occurrence of seismic events. CSES-02, the second satellite of the constellation, will be supplied with a High-Energy Particle Detector (HEPD), composed by a tracker, a trigger system and a calorimeter, designed for the detection of electrons (protons) in the 3-100 (30-200) MeV energy range. The tracker is based on the innovative monolithic pixel sensors ALPIDE, developed for the ALICE experiment, at CERN. The adaptation of the ALPIDE technology to the use in space environments, demanded for ad-hoc solutions for the mechanics, as supporting structures have to withstand structural and vibrational stresses in a wide energy range, maintaining their capability to dissipate the heat generated by ALPIDE operations. This work presents the HEPD-02 tracker, consisting of 150 pixel sensors, supported by Carbon Fiber Reinforced Plastic (CFRPs) and enclosed in an Aluminum frame, focusing on the limited impact that devised solutions have on the physics performance. We report results from an intense campaign of qualification tests, conducted according to the space register and constituting an important premise for using monolithic active pixel sensors in future space cosmic ray experiments.

The micro Advanced Stellar Compass (µASC), an attitude reference for the Juno Magnetic Field investigation, also continuously monitors high energy particle fluxes in Jupiter’s magnetosphere. ...

The MODIS instruments aboard the Terra and Aqua satellites and the VIIRS instruments aboard the SNPP and NOAA-20 satellites each contain several arrays of Si detectors that measure Earth-reflected radiance in the visible and near-infrared spectral range. Even in the absence of incident light, the Si detectors are occasionally excited by high energy charged particles that pass through the spacecraft. These particle radiation events are, fortunately, infrequent enough that they do not lead to significant degradation of the detectors and they do not have a significant impact on the Earth scene radiance images. On the other hand, they are frequent enough that the cumulative data from many years on orbit may provide valuable diagnostic information about the sensors. In this paper, we provide some basic statistics on the frequency and magnitude of the particle excitation events for MODIS and VIIRS and explore the usefulness of this data as a measure of electronic crosstalk. Large amounts of crosstalk can degrade the quality of the Earth images, so it is crucial to have methods to characterize and correct for it on-orbit, which has previously been done for MODIS using lunar image analysis. The particle excitations can manifest as single-pixel spikes in the otherwise dark space view background, which may be an ideal source for evaluating crosstalk. We derive crosstalk coefficients between the NIR band detectors of Terra MODIS, and compare them to coefficients previously derived from lunar observations. The same approach is applied to SNPP VIIRS, which does not show any significant electronic crosstalk. While the HgCdTe detectors used in the MODIS and VIIRS infrared bands can also be excited by particle radiation, the magnitudes of the excitations are much smaller compared to the Si detectors and in general are not large enough to be useful for examining crosstalk.

International audience; BepiColombo Mio (previously called MMO: Mercury Magnetospheric Orbiter) was successfully launched by Ariane 5 from Kourou, French Guiana on October 20, 2018. The Mercury Plasma/Particle Experiment (MPPE) is a comprehensive instrument package onboard Mio spacecraft used for plasma, high-energy particle and energetic neutral atom measurements. It consists of seven sensors including two Mercury Electron Analyzers (MEA1 and MEA2), Mercury Ion Analyzer (MIA), Mass Spectrum Analyzer (MSA), High Energy Particle instrument for electron (HEP-ele), High Energy Particle instrument for ion (HEP-ion), and Energetic Neutrals Analyzer (ENA). Significant efforts were made pre-flight to calibrate all of the MPPE sensors at the appropriate facilities on the ground. High voltage commissioning of MPPE analyzers was successfully performed between June and August 2019 and in February 2020 following the completion of the low voltage commissioning in November 2018. Although all of the MPPE analyzers are now ready to begin observation, the full service performance has been delayed until Mio’s arrival at Mercury. Most of the fields of view (FOVs) of the MPPE analyzers are blocked by the thermal shield surrounding the Mio spacecraft during the cruising phase. Together with other instruments on Mio including Magnetic Field Investigation (MGF) and Plasma Wave Investigation (PWI) that measure plasma field parameters, MPPE will contribute to the comprehensive understanding of the plasma environment around Mercury when BepiColombo/Mio begins observation after arriving at the planet Mercury in December 2025.

The High Energy Particle Detector (HEPD) is one of the scientific payloads of the China Seismo-Electromagnetic Satellite (CSES). The first satellite of the constellation was launched in February 2018 and has been operational in nominal conditions since then. With the launch of the CSES-02 scheduled for mid 2022, the realization of the HEPD-02 detector is ongoing. The Limadou collaboration, in charge of the payload, updated the HEPD design to improve its performance. A Monte Carlo simulation has been developed using the GEANT4 tool, in order to study the response of the new detector to protons, electrons and light nuclei and validate the new design. The comparison between simulation results and data collected during tests will also allow to calibrate the detector response and to train a specifically designed neural network for event reconstruction. We report preliminary results from the simulation and show that the updated HEPD meets the scientific requirements of the CSES-02 mission

The adoption of pixel sensors for space-based tracking detectors requires low power consumption and enhanced heat dissipation to cope with the satellite power and cooling constraints. The High Energy Particle Detector (HEPD) tracker onboard the CSES-02 will be the first application of monolithic active pixel sensors (MAPS) to a satellite-based experiment. This result is achieved with a parallel sparsified readout architecture implemented on a single low-power FPGA chip, which manages the 150 ALPIDE chips of the three-plane tracker. The power consumption is reduced by reading out the ALPIDE chips via the control line instead of the high speed data link, and by distributing the clock only to the portions of the detector crossed by a particle. The readout concept presented in this contribution allows to deal with both the required performance and the power constraints, and is scalable to larger and more complex detectors.

The Fermi bubbles are two large structures above and below the Galactic Plane. They are first discovered by Fermi-LAT and thought to be related to the jet or the wind from the Galactic center. The DArk Matter Particle Explorer (DAMPE) is a space-borne high energy particle telescope aiming at measuring cosmic rays and photons in a broad energy range. In this work, we use 4.8 years of DAMPE photon data to search for the emission from the Fermi Bubbles. We calculate the TS values of the lobes and the significance of its curved spectrum. The obtained spectral parameters are then compared with those from the Fermi-LAT. We also search for the emission from the cocoon in the southeast part of lobes. Since the Galactic diffuse emission (GDE) model is a major source of systematic uncertainty, we also switch to the GDE models calculated with Galprop and evaluate the influence.

The DArk Matter Particle Explorer (DAMPE), a space-based high energy particle detector, has been operated on-orbit for more than five years. The large geometric factor and good charge resolution enable DAMPE to have very good potential to measure cosmic-rays up to 100 TeV. Knowledge of the boron to carbon (B/C) flux ratio is very important in understanding the prop- agation of cosmic rays, especially in TeV energy range. In this contribution, the latest progress of the B/C flux ratio analysis based on the flight data collected by DAMPE during the 5 years of operation, is presented.