Design and construction of the POLAR detector

Produit, N.; Bao, Tianwei; Batsch, T.; Bernasconi, T.; Britvich, I.; Cadoux, F.; Cernuda, I.; Chai, Jun; Dong, Yongwei; Gauvin, N.; Hajdas, W.; Kole, Merlin; Kong, M. N.; Kramert, R.; Liu, J.T.; Liu, X.; Marcinkowski, R.; Orsi, S.; Pohl, M.; Rapin, D.; Rybka, D.; Rutczynska, A.; Shi, Hongyuan; Socha, Patryk; Sun, Jianchao; Song, Liming; Szabelski, J.; Traseira, I.; Xiao, H.; Wang, R.J.; Wen, X. Y.; Wu, Bobing; Zhang, L.; Zhang, Lian Ying; Zhang, S.N.; Zhang, Y.J.; Zwolinska, A.

doi:10.1016/j.nima.2017.09.053

Cited by 57 publications

(55 citation statements)

References 6 publications

(3 reference statements)

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“…The measurements had weak statistical significance and additional observations with more sensitive missions are required. POLAR is a gamma-ray polarimeter mission (50-500 keV) launched with the Chinese Tiangong-2 space station in 2016 [13]. After ∼6 months of operations, data-taking ceased due to instrument malfunction.…”

Section: Introductionmentioning

confidence: 99%

Science prospects for SPHiNX – A small satellite GRB polarimetry mission

Pearce

Eliasson

Iyer

et al. 2019

Astroparticle Physics

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Gamma-ray bursts (GRBs) are exceptionally bright electromagnetic events occurring daily on the sky. The prompt emission is dominated by X-/γ-rays. Since their discovery over 50 years ago, GRBs are primarily studied through spectral and temporal measurements. The properties of the emission jets and underlying processes are not well understood. A promising way forward is the development of missions capable of characterising the linear polarisation of the high-energy emission. For this reason, the SPHiNX mission has been developed for a small-satellite platform. The polarisation properties of incident high-energy radiation (50-600 keV) are determined by reconstructing Compton scattering interactions in a segmented array of plastic and Gd 3 Al 2 Ga 3 O 12 (Ce) (GAGG(Ce)) scintillators. During a two-year mission, ∼200 GRBs will be observed, with ∼50 yielding measurements where the polarisation fraction is determined with a relative error ≤10%. This is a significant improvement compared to contemporary missions. This performance, combined with the ability to reconstruct GRB localisation and spectral properties, will allow discrimination between leading classes of emission models.

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Section: Introductionmentioning

confidence: 99%

Science prospects for SPHiNX – A small satellite GRB polarimetry mission

Pearce

Eliasson

Iyer

et al. 2019

Astroparticle Physics

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“…The trigger decision is based on the number of channels triggered within 100 ns. If the number is higher than two and smaller than a predefined maximum (usually about 10) then the event is accepted and the pulse amplitudes subsequently digitized in the ADC [20,22,23]. Readout data with digitized amplitudes, a timestamp string and some auxiliary information form a module science packet transmitted to the CT.…”

Section: Polar Obox Data Typesmentioning

confidence: 99%

In-flight energy calibration of the space-borne Compton polarimeter POLAR

Xiao

Hajdas²,

et al. 2018

Astroparticle Physics

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POLAR is a compact wide-field space-borne detector for precise measurements of the linear polarisation of hard X-rays emitted by transient sources in the energy range from 50 keV to 500 keV. It consists of a 40×40 array of plastic scintillator bars used as a detection material. The bars are grouped in 25 detector modules. The energy range sensitivity of POLAR is optimized to match with the prompt emission photons from the gamma-ray bursts (GRBs). Polarization measurements of the prompt emission would probe source geometries, emission mechanisms and magnetic structures in GRB jets. The instrument can also detect hard X-rays from solar flares and be used for precise measurement of their polarisation. POLAR was launched into a low Earth orbit on-board the Chinese space-lab TG-2 on September 15th, 2016. To achieve high accuracies in polarisation measurements it is essential to assure both before and during the flight a precise energy calibration. Such calibrations are performed with four low activity 22 Na radioactive sources placed inside the instrument. Energy conversion factors are related to Compton edge positions from the collinear annihilation photons from the sources. This paper presents main principles of the in-flight calibration, arXiv:1710.08918v4 [physics.ins-det] 5 Jun 2018 describes studies of the method based on Monte Carlo simulations and its laboratory verification and finally provides some observation results based on the in-flight data analysis.

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“…The full flight model is shown in figure 3. A full, detailed overview of the instrument design and construction is provided in [27].…”

Section: Polarmentioning

confidence: 99%