Fine‐pitch CdTe detector for hard X‐ray imaging and spectroscopy of the Sun with the FOXSI rocket experiment

Ishikawa, Shin; Katsuragawa, M.; Watanabe, Shin; Uchida, Yuusuke; Takeda, Shin’ichiro; Takahashi, Tadayuki; Glesener, Lindsay; Buitrago-Casas, J. C.; Krucker, S.; Christe, Steven

doi:10.1002/2016ja022631

Cited by 16 publications

(7 citation statements)

References 36 publications

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“…The semiconductor detectors, developed at the Japan Aerospace Exploration Agency Institute of Space and Astronautical Science (JAXA/ISAS), were made of either silicon (Si; five detectors) or cadmium telluride (CdTe; two detectors). The CdTe detectors were added for the FOXSI-2 experiment and offer an improvement compared to Si due to having a higher quantum efficiency above 10 keV (Ishikawa et al 2016). For the Si detectors, the field of view (FOV) is ∼16 × 16 while the FOV for the CdTe detectors is ∼13 × 13 .…”

Section: Foxsi-2 Observations and Datamentioning

confidence: 99%

FOXSI-2 Solar Microflares II: Hard X-ray Imaging Spectroscopy and Flare Energetics

Vievering,

Glesener,

Athiray

et al. 2020

Preprint

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We study the nature of energy release and transfer for two sub-A class solar microflares observed during the second flight of the Focusing Optics X-ray Solar Imager (FOXSI-2 ) sounding rocket experiment on 2014 December 11. FOXSI is the first solar-dedicated instrument to utilize focusing optics to image the Sun in the hard X-ray (HXR) regime, sensitive to the energy range 4-20 keV. Through spectral analysis of the two microflares using an optically thin isothermal plasma model, we find evidence for plasma heated to temperatures of ∼10 MK and emissions measures down to ∼10 44 cm −3 . Though nonthermal emission was not detected for the FOXSI-2 microflares, a study of the parameter space for possible hidden nonthermal components shows that there could be enough energy in nonthermal electrons to account for the thermal energy in microflare 1, indicating that this flare is plausibly consistent with the standard thick-target model. With a solar-optimized design and improvements in HXR focusing optics, FOXSI-2 offers approximately five times greater sensitivity at 10 keV than the Nuclear Spectroscopic Telescope Array (NuSTAR) for typical microflare observations and allows for the first direct imaging spectroscopy of solar HXRs with an angular resolution at scales relevant for microflares. Harnessing these improved capabilities to study the evolution of small-scale events, we find evidence for spatial and temporal complexity during a sub-A class flare. These studies in combination with contemporanous observations by the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory (SDO/AIA) indicate that the evolution of these small microflares is more similar to that of large flares than to the single burst of energy expected for a nanoflare.

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Section: Foxsi-2 Observations and Datamentioning

confidence: 99%

FOXSI-2 Solar Microflares II: Hard X-ray Imaging Spectroscopy and Flare Energetics

Vievering,

Glesener,

Athiray

et al. 2020

Preprint

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“…The past two FOXSI observations were successfully performed with a target energy band of hard X-rays above a few keV [7,8,9,10]. FOXSI has seven modules of X-ray grazing incidence telescopes; we used semiconductor hard X-ray detectors for past launches [11,12,13]. Since the FOXSI telescope has a focusing capability to the soft X-ray energy range, we will replace one detector with the CMOS sensor as the focal plane detector for the FOXSI-3 to realize the first soft X-ray high-speed imaging spectroscopy of the Sun.…”

Section: X-ray Imaging Spectroscopy With a Sounding Rocketmentioning

confidence: 99%

High-speed X-ray imaging spectroscopy system with Zynq SoC for solar observations

Ishikawa

Takahashi

Watanabe

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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We have developed a system combining a back-illuminated Complementary-Metal-Oxide-Semiconductor (CMOS) imaging sensor and Xilinx Zynq System-on-Chip (SoC) device for a soft X-ray (0.5-10 keV) imaging spectroscopy observation of the Sun to investigate the dynamics of the solar corona. Because typical timescales of energy release phenomena in the corona span a few minutes at most, we aim to obtain the corresponding energy spectra and derive the physical parameters, i.e., temperature and emission measure, every few tens of seconds or less for future solar X-ray observations. An X-ray photon-counting technique, with a frame rate of a few hundred frames per second or more, can achieve such results. We used the Zynq SoC device to achieve the requirements. Zynq contains an ARM processor core, which is also known as the Processing System (PS) part, and a Programmable Logic (PL) part in a single chip. We use the PL and PS to control the sensor and seamless recording of data to a storage system, respectively. We aim to use the system for the third flight of the Focusing Optics Solar X-ray Imager (FOXSI-3) sounding rocket experiment for the first photon-counting X-ray imaging and spectroscopy of the Sun.

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“…To achieve high energy resolution and high position resolution at the same time, we have been developing CdTe Double-sided Strip Detectors (CdTe-DSD), based on a CdTe diode [1,2], ranging from a strip pitch of 250 µm to 60 µm [3,4], in combination with dedicated readout electronics [5,6,7]. Imaging is achieved by orthogonal strip electrodes on the two sides of the detectors [8,9,10].…”

Section: Introductionmentioning

confidence: 99%

Imaging and Spectral Performance of a 60 μm Pitch CdTe Double-Sided Strip Detector

Furukawa,

Nagasawa,

Glesener

et al. 2020

Preprint

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We have evaluated the performance of a fine pitch CdTe Double-sided Strip Detector (CdTe-DSD), which was originally developed for the focal plane detector of a hard X-ray telescope to observe the Sun. The detector has a thickness of 750 µm and has 128 strip electrodes with a 60 µm strip pitch orthogonally placed on both sides of the detector and covers an energy range 4 keV to 80 keV. The study of the depth of photon interaction and charge sharing effects are of importance in order to provide good spectroscopic and imaging performance. We study the tail structure observed in the spectra caused by charge trapping and develop a new method to reconstruct the spectra based on induced charge information from both anode and cathode strips. By applying this method, energy resolutions (FWHM) of 0.76 keV and 1.0 keV can be obtained at photon energies of 14 keV and 60 keV, respectively, if the energy difference between the anode and cathode is within 1 keV. Furthermore, the tail component at 60 keV is reduced, and the energy resolution of the 60 keV peak is improved from 2.4 keV to 1.5 keV (FWHM) if the energy difference is greater than 1 keV. In order to study the imaging performance, we constructed a simple imaging system using a 5 mm thick tungsten plate that has a pinhole with a diameter of 100 µm. We utilize a 133 Ba radioisotope of 1 mm in diameter as a target source in combination with a 100 µm slit made from 0.5 mm thickness tungsten. We imaged the 133 Ba source behind the 100 µm slit using a 30 keV peak, with a 100 µm pinhole placed at the center of the source-detector distance. By applying a charge sharing correction between strips, we have succeeded in obtaining a position resolution better than the strip pitch of 60 µm.

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Fine‐pitch CdTe detector for hard X‐ray imaging and spectroscopy of the Sun with the FOXSI rocket experiment

Cited by 16 publications

References 36 publications

FOXSI-2 Solar Microflares II: Hard X-ray Imaging Spectroscopy and Flare Energetics

FOXSI-2 Solar Microflares II: Hard X-ray Imaging Spectroscopy and Flare Energetics

High-speed X-ray imaging spectroscopy system with Zynq SoC for solar observations

Imaging and Spectral Performance of a 60 μm Pitch CdTe Double-Sided Strip Detector

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