Gamma-Ray Burst observations by the high-energy charged particle detector on board the CSES-01 satellite between 2019 and 2021

In this paper we report the detection of five strong Gamma-Ray Bursts (GRBs) by the High-Energy Particle Detector (HEPD-01) mounted on board the China Seismo-Electromagnetic Satellite (CSES-01), operational since 2018 on a Sun-synchronous polar orbit at a $\sim$ 507 km altitude and 97$^\circ$ inclination. HEPD-01 was designed to detect high-energy electrons in the energy range 3 - 100 MeV, protons in the range 30 - 300 MeV, and light nuclei in the range 30 - 300 MeV/n. Nonetheless, Monte Carlo simulations have shown HEPD-01 is sensitive to gamma-ray photons in the energy range 300 keV - 50 MeV, even if with a moderate effective area above $\sim$ 5 MeV. A dedicated time correlation analysis between GRBs reported in literature and signals from a set of HEPD-01 trigger configuration masks has confirmed the anticipated detector sensitivity to high-energy photons. A comparison between the simultaneous time profiles of HEPD-01 electron fluxes and photons from GRB190114C, GRB190305A, GRB190928A, GRB200826B and GRB211211A has shown a remarkable similarity, in spite of the different energy ranges. The high-energy response, with peak sensitivity at about 2 MeV, and moderate effective area of the detector in the actual flight configuration explain why these five GRBs, characterised by a fluence above $\sim$ 3 $\times$ 10$^{-5}$ erg cm$^{-2}$ in the energy interval 300 keV - 50 MeV, have been detected.Comment: Accepted for publication in The Astrophysical Journal (ApJ

Design and performance studies of the calorimeter system for a FCC-hh experiment

The physics reach and feasibility of the Future Circular Collider are currently being investigated in the form of a Conceptual Design Report. The ultimate goal is to collide protons with a centre-of-mass energies of 100 TeV, thus extending the reach of the current HEP facilities. This high-energy regime opens new opportunities for the discovery of physics beyond the standard model, but also new constraints on the detector design. As at 100 TeV a large fraction of the $W, Z, H$ bosons and top quarks are produced with a significant boost, it implies an efficient reconstruction of high energetic objects. The reconstruction of those boosted objects sets the calorimeter performance requirements in terms of energy resolution, containment of highly energetic hadron showers, and high transverse granularity. The detectors designed for the FCC experiments need to tackle harsh conditions of the unprecedented collision energy and instantaneous luminosity. They also must be able to deal with a very high number of collisions per bunch crossings (pile-up). Excellent energy and angular resolution, also for low energetic particles, is therefore needed in order to meet the demands based on the physics benchmarks like Higgs self-couplings. We present the current baseline technologies for the calorimeter system of the FCC-hh reference detector and present first results of the performance studies with the combined calorimeters, meeting the energy resolution goal

Impact of Irradiations by Protons with different Energies on Silicon Sensors

In the frame of the CMS tracker upgrade campaign the radiation damage of oxygen- rich n-type silicon pad diodes induced by 23 MeV and 23 GeV protons was investigated. The diodes were manufactured by Hamamatsu Photonics. After irradiation with 1 MeV neutron equivalent fluences between $1 \times 10^{11} \rm{cm}^{-2}$ and $1.5 \times 10^{15} \rm{cm}^{-2}$, the sensors were electrically characterized by means of capacitance-voltage (CV) and current-voltage (IV) measurements. Current pulses recorded by the Transient Current Technique (TCT) and Charge Collection Eciency (CCE) measurements show a dependence of the bulk damage on the proton energy. At a fluence of $\Phi_{eq} \approx 3 \times 10^{14} \rm{cm}^{-2}$ oxygen-rich n-type diodes demonstrate clear Space Charge Sign Inversion (SCSI) after 23 MeV proton irradiation. This effect does not appear after the irradiation with 23 GeV protons. Moreover, RD50 pad diodes were irradiated with 23 MeV protons, electrically characterized and compared to results obtained after 23 GeV irradiations. Our previous observation on the energy dependence of the radiation damage could be confirmed. In order to get a deeper understanding of the differences of the radiation induced defects, the Deep Level Transient Spectroscopy (DLTS) and Thermally Stimulated Current Technique (TSC) were utilized. Defects with impact on the space charge could be identied and characterized and it was possible to find some hints for the reason of the SCSI after 23 MeV proton irradiation. Moreover, a dependence on the oxygen concentration of the sensors could be observed

Analogue, Digital and Semi-Digital Energy Reconstruction in the CALICE AHCAL

Within the CALICE collaboration different Calorimeter technologies are studied for a future linear collider. These technologies differ in active material, ganularity and readout systems. The Analog Hadronic Calorimeter (AHCal) reads out the signal height of the energy deposition in each calorimeter cell, while the digital HCal detects hits by firing RPC pad sensors above a certain threshold. A 3 bit readout is provided by the semi-digital HCal, which counts hits above three different thresholds per cell. For these three options different energy reconstruction procedures are developed. The analog data can also provide digital information, thus the advantages and disadvantages of different energy reconstruction procedures can be studied.In this work this comparison is done by applying these procedures to AHCal beam test data collected with the 1m3 physics prototype at CERN. These studies are complemented by a full analog energy reconstruction using software compensation techniques to improve the energy resolution based on local energy density informati- on, which is connected to the intrinsic substructure of hadronic showers. For these measurements, the full CALICE calorimeter system, with a silicon-tungsten ECal, and analog HCal and a tail catcher, is used

Analogue, Digital and Semi-Digital Energy Reconstruction in the CALICE AHCAL

Within the CALICE collaboration different calorimeter technologies are studied for a future linear collider. These technologies differ in active material, ganularity and readout systems. The Analog Hadronic Calorimeter (AHCAL) reads out the signal proportional to the energy deposition in each calorimeter cell, while the digital HCAL detects hits by firing RPC pad sensors above a certain threshold. A 3 bit readout is provided by the semi-digital HCAL, which counts hits above three different thresholds per cell. For these three options different energy reconstruction procedures are developed. The analog data can also provide digital information, thus the advantages and disadvantages of different energy reconstruction procedures can be studied.In this work such a comparison is done by applying these procedures to AHCAL beam test data, collected with the 1m3 physics prototype at CERN, and simulated data, generated with GEANT4

Comparison of Two Highly Granular Hadronic Calorimeter Concepts

The CALICE collaboration develops hadron calorimeter technologies with high granularity for future electron-positron linear colliders. These technologies differ in active material, granu- larity and their readout and thus their energy reconstruction schemes. The Analogue Hadron Calorimeter (AHCAL), based on scintillator tiles with Silicon Photomultiplier readout, mea- sures the signal amplitude of the energy deposition in the cells of at most 3 × 3 cm$^2$ size. The Digital, Resistive Plate Chamber (RPC) based, HCAL (DHCAL) detects hits above a certain threshold by firing pad sensors of 1 × 1 cm$^2$. A 2 bit readout is provided by the, also RPC based, Semi-Digital HCAL (SDHCAL), which counts hits above three different thresholds per 1×1cm$^2$ pad. All three calorimeter concepts have been realised in 1m$^3$ prototypes with in- terleaved steel absorber and tested at various test beams.The differences in active medium, granularity and readout have different impacts on the energy resolution and need to be studied independently.This analysis concentrates on the comparison between these technologies by investigating the impact of the different energy reconstruction schemes on the energy resolution of the AHCAL testbeam data and simulation. Additionally, a so-called software compensation algorithm is developed to weight hits dependent on their energy content and correct for the difference in the response to the electromagnetic and hadronic sub-showers (e/h $\neq$ 1) and thus reduce the influence of fluctuations in the π$^0$ generation. The comparison of the energy resolutions re- vealed that it is mandatory for the AHCAL with 3×3cm$^2$ cell size to have analogue signal readout, to apply the software compensation algorithm and thus achieve the best possible en- ergy resolution.The effect of the granularity is studied with a simulation of the AHCAL with 1×1cm$^2$ cell size, and it has been found that to achieve the best possible energy resolution the semi-digital energy reconstruction is sufficient.To study the impact of the active medium, the DHCAL testbeam data was calibrated and the simulation was tuned using the muon and positron data. The energy resolutions, achieved by the DHCAL data and simulation and achieved by the 1 × 1 cm$^2$ AHCAL simulation using the digital energy reconstruction, are successfully used to investigate the influence of the active medium. Finally, the energy resolutions of the data and simulations of the AHCAL, DHCAL and SD- HCAL are compared and the influences discussed

Optimising longitudinal and lateral calorimeter granularity for software compensation in hadronic showers using deep neural networks

We investigate the effect of longitudinal and transverse calorimeter segmentation on event-by-event software compensation for hadronic showers. To factorize out sampling and detector effects, events are simulated in which a single charged pion is shot at a homogenous lead glass calorimeter, split into longitudinal and transverse segments of varying size, and the total energy loss within each segment is used as the signal. As an approximation of an optimal reconstruction, a neural network-based energy regression is trained based on these signals. The architecture is based on blocks of convolutional kernels customized for shower energy regression using local energy densities; biases at the edges of the training dataset are mitigated using a histogram technique. With this approximation, we find that a longitudinal and transverse segment size less than or equal to 0.5 and 1.3 nuclear interaction lengths, respectively, is necessary to achieve an optimal energy measurement. In addition, an intrinsic energy resolution of $$8\%/\sqrt{E}$$ for pion showers is observed

Search for Electron Bursts in the Inner Van Allen Belts with the CSES and NOAA POES Satellites

Earthquake monitoring plays a key role in human life protection, especially in highly populated areas of the Earth. First indications have been found in SAMPEX and NOAA satellite data that particle fluxes of trapped electrons in the Van Allen belts can be correlated to seismic activity on the ground. Within the framework of the CSES mission, a systematic analysis of the electron flux, within the invariant phase space in the L-shell and equatorial pitch angle, has started with the goal to identify short-term variations of the flux (particle bursts) in conjunction with seismic activity. This analysis is based on the statistical evaluation of the flux measurements and built to be potentially implemented in an online monitoring system. The first milestone in that direction has been achieved, providing a stable background estimation. With the injection of artificial signals, the efficiency of the method was evaluated and found to be better than 95% for isolated (one per day) and short (∼3 min) signals with a significance ≥ 5σ above the background. The developed method is set up in a manner to be easily applicable to data from different instruments and satellites. This article presents the studied datasets of the low-energy HEPP instrument onboard the CSES-01 satellite and the electron telescopes of the MEPED detector onboard the NOAA POES-19 satellite, introduces the method for the background estimation, and discusses the first correlation studies of particle bursts with geomagnetic indices obtained within this framework