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Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is a space-borne instrument dedicated to monitoring high-energy transients, thereinto Terrestrial Gamma-ray Flashes (TGFs) and Terrestrial Electron Beams (TEBs). We propose a TGF/TEB search algorithm, with which 147 bright TGFs and 4 TEBs are identified during an effective observation time of $\sim$ 9 months. We show that, with gamma-ray and charged particle detectors, GECAM can effectively identify and distinguish TGFs and TEBs, and measure their temporal and spectral properties in detail. Moreover, we find an interesting TEB consisting of two pulses with a separation of $\sim$ 150 ms, which is expected to originate from a lightning process near the geomagnetic footprint. We also find that the GECAM TGF’s lightning-association ratio is $\sim$ 80\% in the east Asia region using the GLD360 lightning network, which is significantly higher than previous observations.

A charged particle detector (CPD) is one of two main detectors on the GECAM satellite. It was designed to detect charged particles. Electrons and protons are space’s mainly charged particles. So, a research on the proton detection ability of a CPD and deriving the energy response to charged particles of the CPD in the two designed operating modes is important. The proton calibration tests of the CPD under different working modes were carried out at the Heavy Ion Research Facility in Lanzhou. Through testing and analysis, it was concluded that when CPD works in semi-component mode, it can detect the maximum energy, and when working in full-component mode, it can provide better energy resolution.

Silicon microstrip detectors with floating strips have nonuniform charge collection efficiency. This nonuniformity depends on the incident position and incident angle and should be corrected during charge reconstruction. A novel charge reconstruction algorithm, called the charge sharing algorithm, is introduced to correct this nonuniformity. This algorithm assumes that the nonuniformity in charge collection efficiency is due to charge sharing through the capacitors and resistors of silicon microstrip detectors. This charge sharing assumption is tested in this paper using electrical characterization and SPICE simulation.

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) satellite consists of two small satellites. Each GECAM payload contains 25 gamma ray detectors (GRD) and 8 charged particle detectors (CPD). GRD is the main detector which can detect gamma-rays and particles and localize the Gamma-Ray Bursts (GRB),while CPD is used to help GRD to discriminate gamma-ray bursts and charged particle bursts. The GRD makes use of lanthanum bromide (LaBr3) crystal readout by SiPM. As the all available SiPM devices belong to commercial grade, quality assurance tests need to be performed in accordance with the aerospace specifications. In this paper, we present the results of quality assurance tests, especially a detailed mechanism analysis of failed devices during the development of GECAM. This paper also summarizes the application experience of commercial-grade SiPM devices in aerospace payloads, and provides suggestions for forthcoming SiPM space applications., Comment: 13 pages, 23 figures

Each satellite of the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM, mission) consists of 25 SiPM based gamma-ray detectors (GRDs). Although SiPM based GRD has merits of compact size and low bias-voltage, the drift of the SiPM gain with temperature is a severe problem for GRD performance. An adaptive voltage supply source was designed to automatically adjust the SiPM bias voltage to compensate the temperature effects and keep the gain stable. This approach has been proved to be effective during both the on-ground and in-flight tests. The in-flight measured variation of the SiPM gain is within 2%. To reduce the gain non-uniformity of GRDs, an iterative bias voltage adjustment approach is proposed and implemented. The gain non-uniformity is reduced from 17% to 0.6%. In this paper, the gain stabilization and consistency correction approach are presented and discussed in detail., Comment: 14 pages, 21 figures

The DArk Matter Particle Explorer (DAMPE) is a satellite-borne detector for high-energy cosmic rays and $\gamma$-rays. To fully understand the detector performance and obtain reliable physical results, extensive simulations of the detector are necessary. The simulations are particularly important for the data analysis of cosmic ray nuclei, which relies closely on the hadronic and nuclear interactions of particles in the detector material. Widely adopted simulation softwares include the GEANT4 and FLUKA, both of which have been implemented for the DAMPE simulation tool. Here we describe the simulation tool of DAMPE and compare the results of proton shower properties in the calorimeter from the two simulation softwares. Such a comparison gives an estimate of the most significant uncertainties of our proton spectral analysis., Comment: 7 pages, 7 figures, to be published in Chinese Physics Letters

Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is a pair of small satellites designed to monitor the Gamma-Ray Bursts (GRBs), some of them are possibly associated with Gravitational Wave Events (GWE). Each satellite includes twenty-five Gamma-Ray Detectors (GRDs) and eight Charged Particle Detectors (CPDs). GRDs are used to detect X-rays and gamma-rays to realize the observation and location of significant events such as GRBs or other X-ray Bursts (XRBs). Meanwhile, CPDs are used to help GRDs distinguish between GRBs and charged particle events (the majority are electrons) in space. In this paper, we present the electron calibration results of the CPDs, including the energy linearity, energy resolution, angular response, detection efficiency and response in high count rates. Moreover, we use the calibration spectra to verify and correct the mass model of CPD in Geant4 simulation. After the correction, the simulated spectra are in good agreement with the measurements.

The DArk Matter Particle Explorer (DAMPE) can detect electrons and photons from 5 GeV to 10 TeV and charged nuclei from a few tens of GeV to 100 TeV. The silicon–tungstentracker (STK), which is composed of 768 singled-sided silicon microstrip detectors, is one of four subdetectors in DAMPE providing photon conversion , track reconstruction, and charge identification for relativistic charged particles. This paper focuses on the charge identification performance of the STK detector. The charge response depends mainly on the incident angle and the impact position of the incoming particle. To improve the charge resolution, a reconstruction algorithm to correct for these parameters was tested during a test beam campaign conducted with a high-intensity ion beam at CERN. This algorithm was successfully applied to the ion test beam and the ion charge of Z=4 ∼ 10 and was successfully reconstructed for both normal and 9°incident beams.

One of the main purposes of the DArk Matter Particle Explorer (DAMPE) is to measure the cosmic ray nuclei up to several tens of TeV or beyond, whose origin and propagation remains a hot topic in astrophysics. The Plastic Scintillator Detector (PSD) on top of DAMPE is designed to measure the charges of cosmic ray nuclei from H to Fe and serves as a veto detector for discriminating gamma-rays from charged particles. We propose in this paper a charge reconstruction procedure to optimize the PSD performance in charge measurement. Essentials of our approach, including track finding, alignment of PSD, light attenuation correction, quenching and equalization correction are described detailedly in this paper after a brief description of the structure and operational principle of the PSD. Our results show that the PSD works very well and almost all the elements in cosmic rays from H to Fe are clearly identified in the charge spectrum., Comment: 20 pages, 4 figures

The direct detection of gravitational waves has started a new era of gravitational wave astronomy. As an important method for studying the counterparts of gravitational waves, the observation and search of the multi-wavelength radiation of the electromagnetic counterpart of gravitational waves has become the research focus in the field of astronomy. With the advancement of gravitational wave detectors, the number of gravitational wave samples has dramatically increased and the detection of gravitational wave electromagnetic counterparts has become very promising. The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) satellite is a full-sky monitoring telescope designed for detecting high-energy electromagnetic counterparts of gravitational wave events. The main reason for designing a scientific application system of GECAM satellites, which is proposed and designed with an emphasis on discovery, is to ensure the scientific operation of the payload of satellites and achieve the production, storage, processing, calibration, release, and analysis of scientific data. It is also designed to provide technical support and services to scientific users. Based on the exploration and research of the gravitational wave electromagnetic counterpart, this article introduces an innovative monitoring method design of the GECAM scientific application system for the gravitational electromagnetic counterpart, namely, the scheme design of the GECAM scientific application system. The design covers system architecture, interface control, main technical processes, functional composition, and software planning and design. The GECAM satellite is scheduled for launch by the end of 2020. By then, the scientific application system will be able to support the satellite’s in-orbit scientific operation and research.

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is designed to detect gravitational wave gamma-ray bursts and other high-energy transient sources in the energy range of 6 keV–5 MeV. It has the characteristics of all-sky field of view, high sensitivity, good positioning accuracy and wide band coverage. The mission consists of two satellites with each containing 25 gamma-ray detectors (GRD) and 8 charged particle detectors. In this paper, the energy response matrix and in-flight background of each GECAM detector are obtained by Geant4 simulation. The simulation results show that the GECAM has stronger observation ability than the Fermi/GBM in low-energy range. The average in-flight background of a single GRD is about 800 cps, and there are three characteristic peaks that can be used for on-orbit calibration.

The Gamma-Ray Burst (GRB) data analysis is of great importance for the research on Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM); therefore, a user-friendly software tool that covers all the requirements on GRB data analysis has been developed for users. In this paper, the framework and architectural design of GRB data analysis tools software has been described. Meanwhile, details design including the graphical user interface and command line interface were introduced, as well as its installation. The core algorithms of the GRB data analysis were clarified and outlined, including background analysis, calculations on statistical significance, duration and peak flux in given time scale of light curve, fit for deposited energy spectrum, the calculation for the association of GRBs and external trigger event, and a trigger classifier based on Native Bayesian Classification, which offers a rationale and sample for the forward GRB data analysis in GECAM.

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) monitors gamma-ray bursts (GRBs) coincident with gravitational wave events over the whole sky. It also monitors other burst events, such as the high-energy radiation of fast radio bursts, various GRBs, and magnetar bursts. GECAM can measure the energy spectra, light curves, and location of all kinds of bursts. GECAM consists of two small satellites which operate in the same low earth orbit but in opposite geocentric directions. To obtain an all-sky field of view, the two satellites operate in opposite orbital phases. The GECAM payload includes two kinds of detectors: charged particle detector (CPD) and gamma-ray detector (GRD). Each GRD module consists of a LaBr3:Ce scintillator and a SiPM array, and its gamma-ray detection range is 5 keV–5 MeV. GECAM retrieves the locations of events such as GRBs through analyzing the data of the multiple GRDs on both satellites. Meanwhile, the CPD consists of a plastic scintillator and a SiPM array that detects charged particles of energies from 300 keV to 5 MeV. The GECAM distinguishes the charged particle burst events in space by jointly analyzing the GRD and CPD data. The payload electronic box (EBOX) provides in-flight trigger and burst localization. The trigger and burst location data are transmitted by a BeiDou Short Message system, which allows GECAM to guide other telescopes to do follow-up observations.

To evaluate the hazard of space radiation posing to the tissues, it is important to obtain exact fluxes of different radiation particles. The Radiation Gene Box (RGB) onboard SJ-10 spacecraft was an instrument designed to investigate the effects of space environment on the mESCs and drosophila. To derive the dose received by the tissues inside the RGB, the Space Radiation Detector (SRD) was installed inside it. The SRD was designed to derive the fluxes of electron, proton, hellion and gamma rays around it. If the type of the particles, the energies, the fluxes and the conversion coefficients are known, the dose received by the tissues could be evaluated. The SRD was designed as a ΔE-E solid-state telescope. By measuring the energy deposited in the three subdetectors, the particles’ type and their energies could be discriminated. The data of SRD were divided into 15 bins by the types of particles and their energy ranges. The gamma ray flux was higher than any other particle flux inside the RGB, and the electron was the most intense charge particle, while the helium ion was the most harmful radiation to the cells inside the RGB. The dose rate inside the Radiation Gene Box was much higher than in the ground, but the integral dose of 12 days inside the RGB was about 2.13 mSv. It seemed unlikely to have obvious biological effects on the tissues of mice and drosophila.

The DArk Matter Particle Explorer (DAMPE), also known as Wukong in China, launched on December 17, 2015, is a new high energy cosmic ray and {\gamma}-ray satellite-borne observatory in space. One of the main scientific goals of DAMPE is to observe GeV-TeV high energy {\gamma}-rays with accurate energy, angular, and time resolution, to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to {\gamma}-rays, it is challenging to identify {\gamma}-rays with sufficiently high efficiency minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify {\gamma}-rays in DAMPE data based on Monte Carlo simulations, using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected {\gamma}-ray events at $\sim10$ GeV amounts to less than 1% of the selected sample. Finally, we use flight data to verify the effectiveness of the method by highlighting known {\gamma}-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar., Comment: 15 pages,16 figures

DArk Matter Particle Explorer (DAMPE) is a general purpose high energy cosmic ray and gamma ray observatory, aiming to detect high energy electrons and gammas in the energy range 5 GeV to 10 TeV and hundreds of TeV for nuclei. This paper provides a method using machine learning to identify electrons and separate them from gammas,protons,helium and heavy nuclei with the DAMPE data from 2016 January 1 to 2017 June 30, in energy range from 10 to 100 GeV.