A crosstalk and non-uniformity correction method for the Compact Space-borne Compton Polarimeter POLAR

Hualin Xiao; Wojtek Hajdas; Bobing Wu; Nicolas Produit; Tianwei Bao; Tadeusz Batsch; Ilia Britvich; Franck Cadoux; Junying Chai; Yongwei Dong; Neal Gauvin; Minnan Kong; Siwei Kong; Dominik K. Rybka; Catherine Leluc; Lu Li; Jiangtao Liu; Xin Liu; Radoslaw Marcinkowski; Mercedes Paniccia; Martin Pohl; Divic Rapin; Aleksandra Rutczynska; Haoli Shi; Liming Song; Jianchao Sun; Jacek Szabelski; Ruijie Wang; Xing Wen; Hanhui Xu; Laiyu Zhang; Li Zhang; Shuangnan Zhang; Xiaofeng Zhang; Yongjie Zhang; Ania Zwolinska

doi:10.1016/j.astropartphys.2016.06.007

Home/Archive/arXiv

arXiv · 1507.04474

A crosstalk and non-uniformity correction method for the Compact Space-borne Compton Polarimeter POLAR

View original source ↗Read source document ↗Export metadata ↓

Abstract

In spite of extensive observations and numerous theoretical studies in the past decades several key questions related with Gamma-Ray Bursts (GRB) emission mechanisms are still to be answered. Precise detection of the GRB polarization carried out by dedicated instruments can provide new data and be an ultimate tool to unveil their real nature. A novel space-borne Compton polarimeter POLAR onboard the Chinese space station TG2 is designed to measure linear polarization of gamma-rays arriving from GRB prompt emissions. POLAR uses plastics scintillator bars (PS) as gamma-ray detectors and multi-anode photomultipliers (MAPMTs) for readout of the scintillation light. Inherent properties of such detection systems are crosstalk and non-uniformity. The crosstalk smears recorded energy over multiple channels making both non-uniformity corrections and energy calibration more difficult. Rigorous extraction of polarization observable requires to take such effects properly into account. We studied influence of the crosstalk on energy depositions during laboratory measurements with X-ray beams. A relation between genuine and recorded energy was deduced using an introduced model of data analysis. It postulates that both the crosstalk and non-uniformities can be described with a single matrix obtained in calibrations with mono-energetic X- and gamma-rays. Necessary corrections are introduced using matrix based equations allowing for proper evaluation of the measured GRB spectra. Validity of the method was established during dedicated experimental tests. The same approach can be also applied in space utilizing POLAR internal calibration sources. The introduced model is general and with some adjustments well suitable for data analysis from other MAPMT-based instruments.

Explore related subjects

physics.ins-det nucl-ex

Keep this discovery

BibTeX RIS

Hualin Xiao, Wojtek Hajdas, Bobing Wu, Nicolas Produit, Tianwei Bao, Tadeusz Batsch, Ilia Britvich, Franck Cadoux, Junying Chai, Yongwei Dong, Neal Gauvin, Minnan Kong, Siwei Kong, Dominik K. Rybka, Catherine Leluc, Lu Li, Jiangtao Liu, Xin Liu, Radoslaw Marcinkowski, Mercedes Paniccia, Martin Pohl, Divic Rapin, Aleksandra Rutczynska, Haoli Shi, Liming Song, Jianchao Sun, Jacek Szabelski, Ruijie Wang, Xing Wen, Hanhui Xu, Laiyu Zhang, Li Zhang, Shuangnan Zhang, Xiaofeng Zhang, Yongjie Zhang, Ania Zwolinska. 2015-07-16. A crosstalk and non-uniformity correction method for the Compact Space-borne Compton Polarimeter POLAR. https://doi.org/10.1016/j.astropartphys.2016.06.007

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

High-Speed Semi-FE Readout Module for ATLAS MDT at HL-LHC: Design and Production-Level Characterization

The High-Luminosity upgrade of the Large Hadron Collider (HL-LHC) introduces increased demands on the ATLAS Muon Spectrometer, particularly in terms of data throughput, timing distribution and system reliability. The Phase-II Chamber Service Module (CSM) is a key component of the upgraded Monitored Drift Tube (MDT) trigger and readout system, providing a high-speed interface between the front-end electronics and the backend systems. This paper describes the design and implementation of the Phase-II CSM, together with its validation. The results show that the CSM supports two independent optical uplinks, each operating at a line rate of 10.24 Gbps, together with clock distribution and slow control in the expected operating environment. Integration with small-diameter MDT (sMDT) chambers and tests with the prototype L0MDT trigger system are also presented. The CSM boards are now in production and will be used for installation and integration during the upcoming LHC Long Shutdown.

physics.ins-det↗

arXiv2026

Spectral Discrimination of Deposited Gamma-Ray Energies in a Simulated CeBr$_3$ Scintillator

We show that wavelength measurements of individual detected optical photons may provide additional information about gamma-ray energy deposited in a CeBr$_3$ crystal when the detected-photon-count distributions overlap for nearby gamma-ray energies. Monoenergetic 662 and 629 keV gammas are used in a Geant4 simulation of a $25\times25\times20~\mathrm{mm^3}$ CeBr$_3$ crystal. Assuming a light yield of $6.0\times10^4$ photons/MeV, a wavelength-independent photon-detection efficiency of 30%, and a wavelength resolution of $\sigma_{\lambda}=40$ nm, we find that the fraction of photons reconstructed above 385 nm gives an event-level separation of $\sim$ 2 standard deviations between the 662 and 629 keV event populations selected within the same $\sim$ 1%-wide detected-photon-count interval. No timing or reconstructed interaction-position information is used. The result demonstrates, within the present simulation model, that event-dependent optical spectra can retain energy information beyond an undifferentiated photon count.

physics.ins-det↗

arXiv2026

Operation of a negative ion gas time projection chamber without electronegative fill gases

The high fidelity reconstruction of particle tracks in micropatterned gaseous time projection chambers renders this technology ideal for future rare-event searches, including direction-sensitive dark matter experiments. Large drift distances are typically required for such experiments, so that the overall spatial resolution is limited by diffusion. Negative ion drift exhibits lower diffusion than electron drift and is thus an attractive option for realising a large-scale detector. The use of electronegative gases to create negative ions introduces technical challenges, most notably a reduction in gain when compared to conventional gas mixtures. In this study, we demonstrate a new method for negative ion generation via dissociative electron attachment using the conventional molecular fill gas CF$_4$. Our optical measurements of negative ion drift indicate electron attachment lengths of $<$1 mm and comparable gain to electron avalanches. The individual negative ion avalanches were also time-resolved, allowing the number of ions reaching the readout to be counted. We measure an improved energy resolution by single ion counting, relative to an integrated electron avalanche signal measured under identical gain conditions.

physics.ins-det↗