Hard X-ray Polarimeter Research Articles

Hard X-ray polarization measured with a Compton polarimeter at synchrotron radiation facility

A hard X-ray polarimeter with CdTe detectors has been developed for measurement of the degree of X-ray polarization at synchrotron radiation facilities. It utilizes 90° Compton scattering from the low Z targets. Measurements were performed at both facilities of the beamline BL38B1 in SPring-8 and the beamline BL14A in KEK-PF. The degrees of X-ray polarization for 20keV X-rays are 99% and 82% at the BL38B1 in SPring-8 and BL14A in KEK-PF, respectively. The polarization degrees in the energy range of 15 and 40keV correspond to 99.6±0.2% and 96.1±0.2% at the beamline BL38B1 in SPring-8. The analyzing power of the polarimeter was estimated by the Monte Carlo simulation with EGS4. The synchrotron radiation facilities provide highly polarized X-ray beams at energies above 15keV.

Polarization of Hard X-Rays in October-November, 2003 Solar Flares Observed Onboard CORONAS-F Satellite

Hard X-ray radiation from several powerful solar flares was detected in October-November, 2003 by the SPR-N hard X-ray polarimeter onboard CORONAS-F satellite. In the October, 29 solar flare (20:40 - 21:00 UT) the X-ray radiation was strongly polarized (more than 70% of photons with energies 40-100 keV). In the flares 28.10.03 and 04.11.03 the emission was not polarized. The upper limits for the part of polarized photons at the level of tens percents were obtained in these flares.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

Development of hard X-ray polarimeter for $gamma;-ray bursts

The radiation mechanism of gamma-ray bursts (GRBs) is one of the most interesting topics in the field of astrophysics. According to the fireball model, the γ-rays from GRBs should be much polarized. So we have been developing a Compton scattering type hard X-ray polarimeter for GRBs using segmented scintillators and multianode photomultipliers. We carried out basic experiments and computer simulations to investigate the basic performance. As the results, it was recognized that the designed polarimeter can detect the polarization of hard X-rays from GRBs with both the flux 10 times more than that of Crab nebula and the duration of 10 s if the hard X-rays are 8.6% polarized.

Development of hard X-ray polarimeter for γ-ray bursts

The radiation mechanism of gamma-ray bursts (GRBs) is one of the most interesting topics in the field of astrophysics. According to the fireball model, the γ-rays from GRBs should be much polarized. So we have been developing a Compton scattering type hard X-ray polarimeter for GRBs using segmented scintillators and multianode photomultipliers. We carried out basic experiments and computer simulations to investigate the basic performance. As the results, it was recognized that the designed polarimeter can detect the polarization of hard X-rays from GRBs with both the flux 10 times more than that of Crab nebula and the duration of 10 s if the hard X-rays are 8.6% polarized.

Hard X-ray Radiation from Solar Flares in the Second Half of 2001: Preliminary Results of the SPR-N Experiment Onboard the Coronas-F Satellite

The first results of the experiment with the SPR-N hard X-ray (20–100 keV) polarimeter onboard the Coronas-F observatory (the experiment started on August 15, 2001) are presented. Hard X-ray radiation was detected from several solar flares. The spectral and temporal parameters were determined and the polarization was estimated. Comparison with the GOES observations of thermal X-ray radiation shows that hard X-ray bursts occur at the growth phase of the thermal radiation and that they are associated with the bremsstrahlung of energetic electrons precipitating into the solar atmosphere.

Development of a hard X-ray polarimeter for astrophysics

We have been developing a Compton scatter polarimeter for measuring the linear polarization of hard X-rays (100-300 keV) from astrophysical sources. A laboratory prototype polarimeter has been used to successfully demonstrate the reliability of our Monte Carlo simulation code and to demonstrate our ability to generate a polarized photon source in the lab. Our design concept places a self-contained polarimeter module on the front-end of a a 5-inch position sensitive PMT (PSPMT). We are currently working on the fabrication of a science model based on this PSPMT concept. Although the emphasis of our development effort is towards measuring hard X-rays from solar flares, our design has the advantage that it is sensitive over a rather large field-of-view (>1 steradian), a feature that makes it especially attractive for /spl gamma/-ray burst studies.

Development of a hard X-ray polarimeter for solar flares and gamma-ray bursts

We describe recent work on the development of a Compton scatter polarimeter for measuring the polarization of hard X-rays (100-300 keV) from astrophysical sources. Results from measurements with a laboratory prototype are summarized, along with comparisons to Monte Carlo simulations. We also present our latest design concept, which envisions a complete polarimeter module on the front end of a 5-inch position-sensitive PMT. Although the emphasis of our development effort is towards measuring hard X-rays from solar flares, our latest design has the advantage that it is sensitive over a rather large field-of-view (>1 steradian), a feature that makes the design especially attractive for /spl gamma/-ray burst studies.

A new design of hard X-ray polarimeter

A new type of polarimeter has been designed to detect polarized hard X-rays from stellar objects. The performance is investigated by computer simulations based on the characteristics of the polarimeter. The simulations show that the minimum detectable polarization of the hard X-rays from the Crab Nebula is about 13% for balloon observation over two hours. The authors report the design and characteristics of this polarimeter, and the estimation of the detection of polarized hard X-rays from the Crab Nebula. >