In-orbit background for X-ray detectors

Campana, R.

doi:10.48550/arxiv.2205.09359

Cited by 2 publications

(3 citation statements)

References 35 publications

(48 reference statements)

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“…Because of the interaction of charged particles with the spacecraft and the payload structure during the SAA passages, the background increases and decreases immediately upon the entrance and exit of the SAA (Campana 2022), which leads to short-term temporal variation in data. This can be seen in the individual orbital segments of the 1-s light curve (shown in the solid blue line in the top plot of Fig.…”

Section: Data Cleaning For Short-term Variation In Datamentioning

confidence: 99%

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Extending the energy range of AstroSat-CZTI up to 380 keV with compton spectroscopy

Kumar

Chattopadhyay

Vadawale

et al. 2022

Monthly Notices of the Royal Astronomical Society

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The CZTI (Cadmium Zinc Telluride Imager) onboard AstroSat is a high energy coded mask imager and spectrometer in the energy range of 20 - 100 keV. Above 100 keV, the dominance of Compton scattering cross-section in CZTI results in a significant number of 2-pixel Compton events and these have been successfully utilized for polarization analysis of Crab pulsar and nebula (and transients like Gamma-ray bursts) in 100 - 380 keV. These 2-pixel Compton events can also be used to extend the spectroscopic energy range of CZTI up to 380 keV for bright sources. However, unlike the spectroscopy in primary energy range, where simultaneous background measurement is available from masked pixels, Compton spectroscopy requires blank sky observation for background measurement. Background subtraction, in this case, is non-trivial because of the presence of both short-term and long-term temporal variations in the data, which depend on multiple factors like earth rotation and the effect of South Atlantic Anomaly (SAA) regions etc. We have developed a methodology of background selection and subtraction that takes into account for these effects. Here, we describe these background selection and subtraction techniques and validate them using spectroscopy of Crab in the extended energy range of 30 - 380 keV region, and compare the obtained spectral parameters with the INTEGRAL results. This new capability allows for the extension of the energy range of AstroSat spectroscopy and will also enable the simultaneous spectro-polarimetric study of other bright sources like Cygnus X-1.

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Section: Data Cleaning For Short-term Variation In Datamentioning

confidence: 99%

“…X-ray background consists of multiple sources such as cosmic background radiation, induced radioactivity, trapped particles near the SAA, Earth Albedo, etc. (Campana 2022). A careful selection of blank sky observations is necessary to estimate the background due to all these sources correctly.…”

Section: Introductionmentioning

confidence: 99%

Extending the energy range of AstroSat-CZTI up to 380 keV with compton spectroscopy

Kumar

Chattopadhyay

Vadawale

et al. 2022

Monthly Notices of the Royal Astronomical Society

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“…cosmic X-ray background (CXB), cosmic ray particles, geomagnetically trapped particles and albedo (secondary) emission produced in the Earth's atmosphere. [20][21][22] The scintillator based gamma-ray detector is also sensitive to the energetic protons and electrons present in the Van Allen radiation belts (SAA and polar regions). 23 The advantage of our detector design, which employs MPPC sensors is that it operates at relatively low bias voltage and it can also safely measure inside the extreme radiation conditions of the SAA and polar regions.…”

Section: Low Earth Orbit Background Monitoringmentioning

confidence: 99%

Early results from GRBAlpha and VZLUSAT-2

Rípa¹,

Pál²,

Ohno³

et al. 2022

Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray

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We present the detector performance and early science results from GRBAlpha, a 1U CubeSat mission, which is a technological pathfinder to a future constellation of nanosatellites monitoring gamma-ray bursts (GRBs). GRBAlpha was launched in March 2021 and operates on a 550 km altitude sun-synchronous orbit. The gammaray burst detector onboard GRBAlpha consists of a 75×75×5 mm CsI(Tl) scintillator, read out by a dual-channel multi-pixel photon counter (MPPC) setup. It is sensitive in the ∼ 30−900 keV range. The main goal of GRBAlpha is the in-orbit demonstration of the detector concept, verification of the detector's lifetime, and measurement of the background level on low-Earth orbit, including regions inside the outer Van Allen radiation belt and in the South Atlantic Anomaly. GRBAlpha has already detected five, both long and short, GRBs and two bursts were detected within a time-span of only 8 hours, proving that nanosatellites can be used for routine detection of gamma-ray transients. For one GRB, we were able to obtain a high resolution spectrum and compare it with measurements from the Swift satellite. We find that, due to the variable background, the time fraction of about 67 % of the low-Earth polar orbit is suitable for gamma-ray burst detection. One year after launch, the detector

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In-orbit background for X-ray detectors

Cited by 2 publications

References 35 publications

Extending the energy range of AstroSat-CZTI up to 380 keV with compton spectroscopy

Extending the energy range of AstroSat-CZTI up to 380 keV with compton spectroscopy

Early results from GRBAlpha and VZLUSAT-2

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