A Small Satellite Version of a Broad-band Soft X-ray Polarimeter
Herman L. Marshall, Sarah N. T. Heine, Alan Garner, Eric M. Gullikson, H. Moritz Günther, Christopher Leitz, Rebecca Masterson, Eric D. Miller, William Zhang, R… 展开作者
Herman L. Marshall, Sarah N. T. Heine, Alan Garner, Eric M. Gullikson, H. Moritz Günther, Christopher Leitz, Rebecca Masterson, Eric D. Miller, William Zhang, Rozenn Boissay-Malaquin, Ilaria Caiazzo, Deepto Chakrabarty, Rosemary Davidson, Luigi C. Gallo, Ralf K. Heilmann, Jeremy Heyl, Erin Kara, Alan Marscher, Norbert S. Schulz
备注：
20 pages, 8 figures, to appear in Proceedings SPIE, volume 11444
We describe a new implementation of a broad-band soft X-ray polarimeter, substantially based on a previous design. This implementation, the Pioneer Soft X-ray Polarimeter (PiSoX) is a SmallSat, designed for NASA's call for Astrophysics Pioneers, small missions that could be CubeSats, balloon experiments, or SmallSats. As in the REDSoX Polarimeter, the grating arrangement is designed optimally for the purpose of polarimetry with broad-band focussing optics by matching the dispersion of the spectrometer channels to laterally graded multilayers (LGMLs). The system can achieve polarization modulation factors over 90%. For PiSoX, the optics are lightweight Si mirrors in a one-bounce parabolic configuration. High efficiency, blazed gratings from opposite sectors are oriented to disperse to a LGML forming a channel covering the wavelength range from 35 to 75 Angstroms (165 - 350 eV). Upon satellite rotation, the intensities of the dispersed spectra, after reflection and polarizing by the LGMLs, give the three Stokes parameters needed to determine a source's linear polarization fraction and orientation. The design can be extended to higher energies as LGMLs are developed further. We describe examples of the potential scientific return from instruments based on this design.
SPHiNX is a proposed satellite-borne gamma-ray burst polarimeter operating in the energy range 50-500 keV. The mission aims to probe the fundamental mechanism responsible for gamma-ray burst prompt emission through polarisation measurements. Optimising the signal-to-background ratio for SPHiNX is an important task during the design phase. The Geant4 Monte Carlo toolkit is used in this work. From the simulation, the total background outside the South Atlantic Anomaly (SAA) is about 323 counts/s, which is dominated by the cosmic X-ray background and albedo gamma rays, which contribute ~60% and ~…
We describe the current status of the design and development of a Thomson X-ray polarimeter suitable for a small satellite mission. Currently we are considering two detector geometries, one using rectangular detectors placed on four sides of a scattering element and the other using a single cylindrical detector with the scattering element at the center. The rectangular detector configuration has been fabricated and tested. The cylindrical detector is currently under fabrication. In order to compensate any pointing offset of the satellite, a collimator with a flat topped response has been devel…
PolarLight is a compact soft X-ray polarimeter onboard a CubeSat, which was launched into a low-Earth orbit on October 29, 2018. In March 2019, PolarLight started full operation, and since then, regular observations with the Crab nebula, Sco X-1, and background regions have been conducted. Here we report the operation, calibration, and performance of PolarLight in the orbit. Based on these, we discuss how one can run a low-cost, shared CubeSat for space astronomy, and how CubeSats can play a role in modern space astronomy for technical demonstration, science observations, and student training.
We are developing instrumentation for a telescope design capable of measuring linear X-ray polarization over a broad-band using conventional spectroscopic optics. Multilayer-coated mirrors are key to this approach, being used as Bragg reflectors at the Brewster angle. By laterally grading the multilayer mirrors and matching to the dispersion of a spectrometer, one may take advantage of high multilayer reflectivities and achieve modulation factors over 50% over the entire 0.2-0.8 keV band. We present progress on laboratory work to demonstrate the capabilities of an existing laterally graded mul…
A new NASA Pioneer: the Globe Orbiting Soft X-ray Polarimeter (GOSoX)
Massachusetts Institute of Technology（麻省理工学院）；NASA Marshall Space Flight Center（美国国家航空航天局马歇尔太空飞行中心）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Eberhard Karls University of Tübingen（蒂宾根大学）；University College London（伦敦大学学院）；Universita degli Studi di Padova（帕多瓦大学）；Louisiana State University and A&M College（路易斯安那州立大学）；University of Maryland Baltimore County（马里兰大学巴尔的摩县分校）；St. Mary’s University（圣玛丽大学）
The Lightweight Asymmetry and Magnetism Probe (LAMP) is a micro-satellite mission concept dedicated for astronomical X-ray polarimetry and is currently under early phase study. It consists of segmented paraboloidal multilayer mirrors with a collecting area of about 1300 cm^2 to reflect and focus 250 eV X-rays, which will be detected by position sensitive detectors at the focal plane. The primary targets of LAMP include the thermal emission from the surface of pulsars and synchrotron emission produced by relativistic jets in blazars. With the expected sensitivity, it will allow us to detect pol…
We report on the optimization of the hard X-ray polarimeter X-Calibur for a high-altitude balloon-flight in the focal plane of the InFOCμS X-ray telescope from Fort Sumner (NM) in Fall 2013. X-Calibur combines a low-Z scintillator slab to Compton-scatter photons with a high-Z Cadmium Zinc Telluride (CZT) detector assembly to photo-absorb the scattered photons. The detector makes use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. X-Calibur achieves a high detection efficiency of order unity and reaches a sensitivity close to th…
A soft X-ray, beam-splitting, multilayer optic has been developed for the Bragg Reflection Polarimeter (BRP) on the NASA Gravity and Extreme Magnetism Small Explorer Mission (GEMS). The optic is designed to reflect 0.5 keV X-rays through a 90 degree angle to the BRP detector, and transmit 2-10 keV X-rays to the primary polarimeter. The transmission requirement prevents the use of a thick substrate, so a 2 micron thick polyimide membrane was used. Atomic force microscopy has shown the membrane to possess high spatial frequency roughness less than 0.2 nm rms, permitting adequate X-ray reflectanc…
We present a novel X-ray assembly of functionally related instrument blocks intended to measure solar flare and active region (AR) spectra from within the Russian instrument complex KORTES, to be mounted aboard the International Space Station (ISS). SolpeX consists of three blocks: fast-rotating multiple flat crystal Bragg spectrometer, pin-hole X-ray spectral imager and Bragg polarimeter. This combination of measuring blocks will offer an opportunity to detect/measure possible X-ray polarization in soft X-ray emission lines/continuum and record spectra of solar flares, in particular during th…
The measurement of the linear polarization is one of the hot topics of High Energy Astrophysics. Gas detectors based on photoelectric effect have paved the way for the design of sensitive instruments and mission proposals based on them have been presented in the last few years in the energy range from about 2 keV to a few tens of keV. As well, a number of polarimeters based on Compton scattering are approved or discussed for launch on-board balloons or space satellites at higher energies. These instruments are typically dedicated to pointed observations with narrow field of view telescopes or …
POLAR is a space-borne hard X-ray Compton polarimeter built by a collaboration of institutes from Switzerland, China and Poland. Precise detection of the polarization can be a powerful tool to unveil emission mechanisms of e.g. Gamma-Ray Bursts (GRB) or Solar Flares (SF). POLAR is equipped with an array of 1600 scintillator bars dimensioned for precise measurements of the polarization of hard X-rays in the energy range from 50 keV to 500 keV. The instrument was launched into space on September 15th, 2016 on-board the Chinese Space Laboratory TG-2 for up to 3 years long observation period. Tele…
Application of cubesats in astronomical observations has been getting more and more mature in recent years. Here we report a concept study of a small Compton polarimeter to fly on a cubesat for observing polarization of soft gamma-rays from a black-hole X-ray binary, Cygnus X-1. Polarization states provide very useful diagnostics on the emission mechanism and the origin of those gamma rays. In our study, we conducted Monte Carlo simulations to decide the basic design of this small polarimeter. Silicon detectors and cerium bromide scintillators were employed in this study. We estimated its on-a…
We review the basic principles of X-ray polarimetry and current detector technologies based on the photoelectric effect, Bragg reflection, and Compton scattering. Recent technological advances in high-spatial-resolution gas-filled X-ray detectors have enabled efficient polarimeters exploiting the photoelectric effect that hold great scientific promise for X-ray polarimetry in the 2-10 keV band. Advances in the fabrication of multilayer optics have made feasible the construction of broad-band soft X-ray polarimeters based on Bragg reflection. Developments in scintillator and solid-state hard X-…
X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly-sensitive gamma-ray i…
Astronomical X-ray polarimetry was first explored in the end of the 60's by pioneering rocket instruments. The craze arising from the first discoveries on stellar and supernova remnant X-ray polarization led to the addition of X-ray polarimeters on-board of early satellites. Unfortunately, the inadequacy of the diffraction and scattering technologies required to measure polarization with respect to the constraints driven by X-ray mirrors and detectors, coupled to long integration times, slowed down the field for almost 40 years. Thanks to the development of new, highly sensitive, compact X-ray…
We describe a low-cost, open-access, CubeSat-based calibration instrument that is designed to support ground-based and sub-orbital experiments searching for various polarization signals in the cosmic microwave background (CMB). All modern CMB polarization experiments require a robust calibration program that will allow the effects of instrument-induced signals to be mitigated during data analysis. A bright, compact, and linearly polarized astrophysical source with polarization properties known to adequate precision does not exist. Therefore, we designed a space-based millimeter-wave calibratio…
The maturity of current detectors based on technologies that range from solid state to gases renewed the interest for X-ray polarimetry, raising the enthusiasm of a wide scientific community to improve the performance of polarimeters as well as to produce more detailed theoretical predictions. We will introduce the basic concepts about measuring the polarization of photons, especially in the X-rays, and we will review the current state of the art of polarimeters in a wide energy range from soft~to hard X-rays, from solar flares to distant astrophysical sources. We will introduce relevant examp…
The autonomous control system of PoGOLite is presented. PoGOLite is a balloon borne X-ray polarimeter designed to observe point sources. To obtain scientific data with optimal efficiency, independent of the ground connection, the payload control system has been made autonomous in most functions. The overall system architecture and the interconnections between components, as well as the automation philosophy and software, are described. Results of performance tests are given.
The Advanced Energetic Pair Telescope gamma-ray polarimeter uses a time projection chamber for measuring pair production events and is expected to generate a raw instrument data rate four orders of magnitude greater than is transmittable with typical satellite data communications. GammaNet, a convolutional neural network, proposes to solve this problem by performing event classification on-board for pair production and background events, reducing the data rate to a level that can be accommodated by typical satellite communication systems. In order to train GammaNet, a set of 1.1x10^6 pair prod…
The physical processes postulated to explain the high-energy emission mechanisms of compact astrophysical sources often yield polarised soft gamma rays (X-rays). PoGOLite is a balloon-borne polarimeter operating in the 25-80 keV energy band. The polarisation of incident photons is reconstructed using Compton scattering and photoelectric absorption in an array of phoswich detector cells comprising plastic and BGO scintillators, surrounded by a BGO side anticoincidence shield. The polarimeter is aligned to observation targets using a custom attitude control system. The maiden balloon flight is s…
POLAR is a novel compact Compton X-ray polarimeter designed to measure the linear polarization of the prompt emission of Gamma Ray Bursts (GRB) and other strong transient sources such as soft gamma repeaters and solar flares in the energy range 50-500 keV. A detailed measurement of the polarization from astrophysical sources will lead to a better understanding of the source geometry and emission mechanisms. POLAR is expected to observe every year several GRBs with a minimum detectable polarization smaller than 10%, thanks to its large modulation factor, effective area, and field of view. POLAR…
Background The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) is primarily designed to spot gamma-ray bursts corresponding to gravitational waves. In order to achieve stable observations from various astronomical phenomena, the payload performance need to be monitored during the in-orbit operation. Method This article describes the design and implementation of GECAM satellite payload performance monitoring (GPPM) software. The software extracts the payload status and telescope observations (light curves, energy spectrums, characteristic peak fitting of energ…
NISP, a multifaceted near-infrared instrument for the upcoming 2.5m IR telescope at MIRO Gurushikhar, Mount Abu, Rajasthan, India is being developed at PRL, Ahmedabad. NISP will have wide (FOV = 10' x 10') field imaging, moderate (R=3000) spectroscopy and imaging polarimetry operating modes. It is designed based on 0.8 to 2.5 micron sensitive, 2048 X 2048 HgCdTe (MCT) array detector from Teledyne. Optical, Mechanical and Electronics subsystems are being designed and developed in-house at PRL. HAWAII-2RG (H2RG) detector will be mounted along with controlling SIDECAR ASIC inside LN2 filled cryog…
Gamma-ray polarization offers a unique probes into the geometry of the gamma-ray emission process in celestial objects. The Soft Gamma-ray Detector (SGD) onboard the X-ray observatory Hitomi is a Si/CdTe Compton camera and is expected to be an excellent polarimeter, as well as a highly sensitive spectrometer due to its good angular coverage and resolution for Compton scattering. A beam test of the final-prototype for the SGD Compton camera was conducted to demonstrate its polarimetric capability and to verify and calibrate the Monte Carlo simulation of the instrument. The modulation factor of …
One of the primary objectives of small satellites is to reduce the costs associated with spacecraft development and operations as compared to traditional spacecraft missions. Small satellite missions are generally able to reduce mission planning, hardware, integration, and operational costs; however, small satellite missions struggle with reducing software development and testing costs. This paper presents the case study of the NASA Operational Simulator for Small Satellites (NOS3), a software-only simulation framework that was developed for the Simulation-to-Flight 1 (STF-1) 3U CubeSat missio…
TSUBAME is a micro-satellite that the students of Tokyo Institute of Technology took the lead to develop for measuring hard X-ray polarization of Gamma-Ray Bursts(GRBs) in order to reveal the nature of the central engine of GRBs. TSUBAME has two instruments: Wide-field Burst Monitor (WBM) and Hard X-ray Compton Polarimeter (HXCP). We aim to start observing with HXCP in 15 seconds by pointing the spacecraft using Control Moment Gyro. In August 2014, we assembled TSUBAME and performed an integration test during ~2 weeks.TSUBAME by communication tests with Cute-1.7+APDII in orbit. On Nov 6 2014, …
The CUbesat Solar Polarimeter (CUSP) project aims to develop a constellation of two CubeSats orbiting the Earth to measure the linear polarisation of solar flares in the hard X-ray band by means of a Compton scattering polarimeter on board of each satellite. CUSP will allow to study the magnetic reconnection and particle acceleration in the flaring magnetic structures. CUSP is a project approved for a Phase A study by the Italian Space Agency in the framework of the Alcor program aimed to develop CubeSat technologies and missions.
X-ray spectrometer is one of the satellite payloads on Chang'E-2 satellite. The soft X-ray detector is one of the device on X-ray spectrometer which is designed to detect the major rock-forming elements within 0.5-10keV range on lunar surface. In this paper, energy linearity and energy resolution calibration is done using a weak Fe55 source, while temperature and time effect is considered not take big error. The total uncertainty is estimated to be within 5% after correction.
Recently CMOS (complementary metal-oxide semiconductor) sensors have progressed to a point where they may offer improved performance in imaging x-ray detection compared to the CCDs often used in x-ray satellites. We demonstrate x-ray detection in the soft x-ray band (250-1700 eV) by a commercially available back-illuminated Sony IMX290LLR CMOS sensor using the Advanced Photon Source at the Argonne National Laboratory. While operating the device at room temperature, we measure energy resolutions (FWHM) of 48 eV at 250 eV and 83 eV at 1700 eV which are comparable to the performance of the Chandr…
X-ray polarimetry is still largely uncharted territory. With the upcoming launch of IXPE, we will learn a lot more about X-ray polarization at energies above 2 keV, but so far no current or accepted mission provides observational capabilities below 2 keV. We present ray-tracing results for a small orbital mission that could be launched within NASA's Pioneer or SmallSat cost-cap to provide X-ray polarimetry below 2 keV. The design is based on the use of laterally-graded multi-layer (ML) mirrors, a concept that we have developed theoretically for the REDSoX Polarimeter, for which most components…
Development of a one-dimensional position sensitive detector for Compton X-ray polarimeters
Physical Research Laboratory（物理研究实验室）；INAF − - Istituto di Astrofisica e Planetologia Spaziali di Roma（罗马天体物理学和行星学研究所）；Kavli Institute of Particle Astrophysics and Cosmology, Stanford University（斯坦福大学卡弗里粒子天体物理学与宇宙学研究所）
We present experimental studies on the charge transfer inefficiency (CTI) of charge-coupled device (CCD) developed for the soft X-ray imaging telescope, Xtend, aboard the XRISM satellite. The CCD is equipped with a charge injection (CI) capability, in which sacrificial charge is periodically injected to fill the charge traps. By evaluating the re-emission of the trapped charge observed behind the CI rows, we find that there are at least three trap populations with different time constants. The traps with the shortest time constant, which is equivalent to a transfer time of approximately one pi…
We present continued development of laterally graded multilayer mirrors (LGMLs) for a telescope design capable of measuring linear X-ray polarization over a broad spectral band. The multilayer-coated mirrors are used as Bragg reflectors at the Brewster angle. By matching to the dispersion of a spectrometer, one may take advantage of high multilayer reflectivities and achieve modulation factors over 50% over the entire 0.2-0.8 keV band. In Phase II of the polarimetry beam-line development, we demonstrated that the system provides 100% polarized X-rays at 0.525 keV (Marshall et al. 2013). Here, …
The Educational Irish Research Satellite, known as EIRSAT-1, is a student-led project to design, build, test and launch Ireland's first satellite. The on-board software for this mission is being developed using Bright Ascension's GenerationOne Flight Software Development Kit. This paper provides an overview of this kit and of EIRSAT-1's on-board software design. Drawing on the team's contrasting experience with writing entirely custom firmware for the mission's science payloads, this work discusses the impact of using a kit on the software development process. The challenges associated with th…
Development and Evaluation of a CNN-Based Charged-Particle Event Rejection Algorithm for Soft X-ray Detection in a pnCCD-Based Satellite System
RIKEN（理化学研究所）；Kanazawa University（金泽大学）；Aoyama Gakuin University（青山学院大学）；Kwansei Gakuin University（关西学院大学）；Institute of Space and Astronautical Science（宇宙科学研究所）；Kanto Gakuin University（关东学院大学）；Konan University（神户大学）；PNSensor GmbH.（PNSensor有限公司）
CubeSats are small satellites used for scientific experiments because they cost less than full sized satellites. Each CubeSat uses an on-board computer. The on-board computer performs sensor measurements, data processing, and CubeSat control. The challenges of designing an on-board computer are costs, radiation, thermal stresses, and vibrations. An on-board computer was designed and implemented to solve these challenges. The on-board computer used special components to mitigate radiation effects. Software was also used to provide redundancies in cases of faults. This paper may aid future space…
This paper presents a unique approach to the problem of calculating revisit time metrics for different satellite orbits, sensor geometries, and constellation configurations with application to early lifecycle design and optimisation processes for Earth observation missions. The developed semi-analytical approach uses an elliptical projected footprint geometry to provide an accuracy similar to that of industry standard numerical orbit simulation software but with an efficiency of published analytical methods. Using the developed method, extensive plots of maximum revisit time are presented for …
The Crab nebula is so far the only celestial object with a statistically significant detection in soft x-ray polarimetry, a window that has not been explored in astronomy since the 1970s. However, soft x-ray polarimetry is expected to be a sensitive probe of magnetic fields in high energy astrophysical objects including rotation-powered pulsars and pulsar wind nebulae. Here we report the re-detection of soft x-ray polarisation after 40 years from the Crab nebula and pulsar with PolarLight, a miniature polarimeter utilising a novel technique onboard a CubeSat. The polarisation fraction of the C…
This paper presents a system-level engineering approach for the preliminary coverage performance analysis and the design of a generic Global Navigation Satellite System (GNSS) constellation. This analysis accounts for both the coverage requirements and the robustness to transient or catastrophic failures of the constellation. The European GNSS, Galileo, is used as reference case to prove the effectiveness of the proposed tool. This software suite, named GNSS Coverage Analysis Tool (G-CAT), requires as input the state vector of each satellite of the constellation and provides the performance of…
