Abstract
Richardson–Lucy (RL) deconvolution is one of the classical methods widely used in X-ray astronomy and other areas. Amid recent progress in image processing, RL deconvolution still leaves ...much room for improvement under realistic situations. One direction is to include the positional dependence of a point-spread function (PSF), so-called RL deconvolution with a spatially variant PSF (RL
sv
). Another is the method of estimating a reliable number of iterations and their associated uncertainties. We developed a practical method that incorporates the RL
sv
algorithm and the estimation of uncertainties. As a typical example of bright and high-resolution images, the Chandra X-ray image of the supernova remnant Cassiopeia A was used in this paper. RL
sv
deconvolution enables us to uncover the smeared features in the forward/backward shocks and jet-like structures. We constructed a method to predict the appropriate number of iterations using statistical fluctuation of the observed images. Furthermore, the uncertainties were estimated by error propagation from the last iteration, which was phenomenologically tested with the observed data. Thus, our method is a practically efficient framework to evaluate the time evolution of the remnants and their fine structures embedded in high-resolution X-ray images.
Optical transition-edge sensor (TES) is a single-photon detector for the visible to near-infrared wavelength range. Recently, it has been applied to various applications such as quantum information, ...quantum computing, bio-imaging, and low-mass dark matter search. The challenge of implementing an optical TES in these applications lies in the need for a large number of channels. We have been developing a system that guarantees a large number of pixels by using an optical TES array and multiplexing readout method. Microwave SQUID multiplexing is a frequency multiplexing method that enables a wide readout frequency bandwidth by using a frequency of several GHz as a carrier wave. In this paper, we report the first demonstration of simultaneous readout of optical TESs by microwave SQUID multiplexing with a sampling frequency of 5 MHz.
Abstract
We examined the X-ray and radio spatial structure at the eastern ear of the W 50/SS 433 system to clarify a characteristic feature of the termination region of the SS 433 jet, and found that ...a hot spot ahead of the filament structure, which is considered to be a terminal shock of the SS 433 eastern jet, is clearly different from a single point source. The detailed spatial structure of the X-ray emission is finely resolved by Chandra observations, showing that there are two sources. By comparing the point-spread function of Chandra with the radial profiles of the two sources, the northern one is clearly more extended than a point source while the other seems marginally extended. Since there are no point sources nearby, the northern hot spot is likely a localized diffuse source. The northern hot spot spatially corresponds to the peak of the radio emission. Its spatial correlation is confirmed by an X-ray image using XMM-Newton. The X-ray spectra of the two sources are reproduced by a single absorbed power-law but the column density of the northern part is larger by a factor of ∼3. When a radiation model comprising synchrotron emission and inverse Compton emission is applied to the spectral energy distribution of the northern hot spot, the emission from this spot can be explained by the radiation from an electron population accelerated up to 30 TeV in a magnetic field strength of B ≲ 50 μG. This model also agrees with the radio and X-ray data, as well as the upper limit of gamma-ray emission obtained by the Fermi satellite.
Accurate determination of cerium (Ce) valence state is important for interpreting the Ce anomaly in geological archives for (paleo)redox reconstruction. However, the routine application of Ce L3-edge ...X-ray absorption near-edge structure (XANES) spectroscopy for detecting trace Ce in geological samples can often be restricted by coexisting titanium (Ti) due to the proximity of their fluorescence emission lines. Therefore, the signal-to-noise ratio of Ce L3-edge XANES spectra may not be sufficiently high for high-quality spectroscopic analysis. This study introduces a semi-quantitative approach appropriate for Ti-rich, Ce-dilute geological materials by synchrotron-based X-ray measurement at the Ce L2-edge. First, the results confirm that Ce L2-edge XANES spectra are able to avoid overlapping Ti Kβ emissions and provide more reliable information on the Ce valence state in Ti-rich materials relative to L3-edge XANES. Moreover, the application of transition-edge sensor (TES) could reach the higher sensitivity with better energy resolution than conventional silicon drift detector (SDD) to detect fluorescence X-ray (Ce Lβ1). The investigation on bauxites developed from the Columbia River Basalts shows that combining Ce L2-edge XANES and TES allows for resolving weak Ce fluorescence lines at the L2-edge from Ti-rich, Ce-dilute samples (Ti/Ce mass ratio up to ∼6000, tens of ppm Ce). The outcome emphasizes the practical possibility of investigating Ce redox state in Ti-rich geological samples.
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•TES detectors reach much higher energy resolution as compared to SDD detectors.•This paves the way for probing Ce oxidation state in Ti-rich geological samples.•Cerium L2-edge XANES-LCF using a TES detector could be achieved for Ti/Ce up to 6000.
A 320-keV spectrometer based on an 8-pixel transition edge sensor (TES) has been developed. It involves a unique 7-μm thick membrane consisting of silicon dioxide (SiO 2 ), silicon nitride (Si x N y ...), and SiO 2 . This membrane supports a 0.8-mm thick Sn absorber with suitable stopping power for photon energy E = 320 keV and is applicable up to E <inline-formula><tex-math notation="LaTeX"> \approx </tex-math></inline-formula> 0.7 MeV. Our trilayer membrane exhibits the same thermal conductance as conventional 1-μm thick Si x N y one, i.e., G <inline-formula><tex-math notation="LaTeX"> \approx </tex-math></inline-formula> 1.2 nW/K at the critical temperature of 115 mK. We carry out the spectroscopy using a 51 Cr radiation source and simultaneously read out the 8 pixels with a microwave SQUID multiplexer. We find a linear broadening trend between the pulse peak and pulse area, even after a correction of the baseline drift due to time-varied temperature of our cryocooler. Based on the relationship, we analyze the data and succeed in avoiding degradation of the energy resolution in spectra. The resultant full-width-half-maximum (FWHM) energy resolution Δ E FWHM of the measured 6 pixels satisfies Δ E FWHM <1.6Δ E NEP where Δ E NEP is the noise-equivalent-power energy resolution. The best energy resolution among them is Δ E FWHM = 159 eV at 320 keV. This is 5 times as high as that of high-purity germanium detectors at 77 K and the best resolving power for gamma-ray TESs operated at E >220 keV to our knowledge.
In this study, we successfully applied a transition-edge sensor (TES) spectrometer as a detector for microbeam X-ray measurements from a synchrotron X-ray light source in the hard X-ray region to ...determine uranium (U) distribution at the micro-scale and its chemical species in biotite obtained from a U mine. It is difficult to separate the fluorescent X-ray of the U Lα
1
line at 13.615 keV from that of the Rb Kα line at 13.395 keV in the X-ray fluorescence spectrum with an energy resolution of approximately 220 eV using a conventional silicon drift detector (SDD). Meanwhile, the fluorescent X-rays of U Lα
1
and Rb Kα were fully separated by a TES with 50 eV energy resolution at an energy of around 13 keV. The successful peak separation by the TES led to an accurate mapping analysis of trace U in micro-X-ray fluorescence measurements and a decrease in the signal-to-background ratio in micro-X-ray absorption near edge structure spectroscopy. Thus, it could be a powerful tool for studying the U distribution and speciation in various environmental samples.
Interference free distribution and speciation analysis of uranium are achieved by using a transition-edge sensor for microbeam X-ray measurements in the hard X-ray region.
A superconducting transition-edge sensor (TES) microcalorimeter is an ideal X-ray detector for experiments at accelerator facilities because of good energy resolution and high efficiency. To study ...the performance of the TES detector with a high-intensity pulsed charged-particle beam, we measured X-ray spectra with a pulsed muon beam at the Japan Proton Accelerator Research Complex (J-PARC) in Japan. We found substantial temporal shifts of the X-ray energy correlated with the arrival time of the pulsed muon beam, which was reasonably explained by pulse pileup due to the incidence of energetic particles from the initial pulsed beam.
Accurate determination of cerium (Ce) valence state is important for interpreting the Ce anomaly in geological archives for (paleo)redox reconstruction. However, the routine application of Ce L
-edge ...X-ray absorption near-edge structure (XANES) spectroscopy for detecting trace Ce in geological samples can often be restricted by coexisting titanium (Ti) due to the proximity of their fluorescence emission lines. Therefore, the signal-to-noise ratio of Ce L
-edge XANES spectra may not be sufficiently high for high-quality spectroscopic analysis. This study introduces a semi-quantitative approach appropriate for Ti-rich, Ce-dilute geological materials by synchrotron-based X-ray measurement at the Ce L
-edge. First, the results confirm that Ce L
-edge XANES spectra are able to avoid overlapping Ti K
emissions and provide more reliable information on the Ce valence state in Ti-rich materials relative to L
-edge XANES. Moreover, the application of transition-edge sensor (TES) could reach the higher sensitivity with better energy resolution than conventional silicon drift detector (SDD) to detect fluorescence X-ray (Ce L
). The investigation on bauxites developed from the Columbia River Basalts shows that combining Ce L
-edge XANES and TES allows for resolving weak Ce fluorescence lines at the L
-edge from Ti-rich, Ce-dilute samples (Ti/Ce mass ratio up to ∼6000, tens of ppm Ce). The outcome emphasizes the practical possibility of investigating Ce redox state in Ti-rich geological samples.
