Design and Performance of a TES X-ray Microcalorimeter Array for Energy Dispersive Spectroscopy on Scanning Transmission Electron Microscope

Muramatsu, H.; Nagayoshi, K.; Hayashi, T.; Sakai, Kazuhiro; Yamamoto, Ryo; Mitsuda, Kazuhisa; Yamasaki, Noriko Y.; Maehata, Keisuke; Hara, Toru

doi:10.1007/s10909-016-1547-3

Cited by 21 publications

(13 citation statements)

References 7 publications

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“…This degradation caused by the crosstalk effect is estimated to be 0.6 eV at 5.9 keV at a count rate of 500 cps/pixel. Muramatsu et al [6] shows that the energy resolution of FWHM ∼7.9 eV (90 % ∼ 10 eV) at 5.9 keV when the one pixel of our 64 TES array is operated. As the goal of the energy resolution of the STEM/TES project is 10 eV, there is still a margin of 6.1 eV which to be square summed.…”

Section: Simulation and Verification Of The Crosstalk Effectmentioning

confidence: 79%

Common Bias Readout for TES Array on Scanning Transmission Electron Microscope

et al. 2016

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A transition edge sensor (TES) microcalorimeter array as an X-ray sensor for a scanning transmission electron microscope system is being developed. The technical challenge of this system is a high count rate of ∼5000 counts/second/array. We adopted a 64 pixel array with a parallel readout. Common SQUID bias, and common TES bias are planned to reduce the number of wires and the resources of a room temperature circuit. The reduction rate of wires is 44 % when a 64 pixel array is read out by a common bias of 8 channels. The possible degradation of the energy resolution has been investigated by simulations and experiments. The bias fluctuation effects of a series connection are less than those of a parallel connection. Simple calculations expect that the fluctuations of the common SQUID bias and common TES bias in a series connection are 10 −7 and 10 −3 , respectively. We constructed 8 SQUIDs which are connected to 8 TES outputs and a room temperature circuit for common bias readout and evaluated experimentally. Our simulation of crosstalk indicates that at an X-ray event rate of 500 cps/pixel, crosstalk will broaden a monochromatic line by about 0.01 %, or about 1.5 eV at 15 keV. Thus, our design goal of 10 eV energy resolution across the 0.5-15 keV band should be achievable.

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Section: Simulation and Verification Of The Crosstalk Effectmentioning

confidence: 79%

Common Bias Readout for TES Array on Scanning Transmission Electron Microscope

et al. 2016

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“…The TES comprises a bilayer of Ti and Au, in which the thicknesses are, respectively, 40 nm and 110 nm, and the layers were deposited on SiN x by DC magnetron sputtering. The Al wiring for the TES readout electrode was deposited by RF sputtering and was formed by the etching and liftoff processes [9] (Fig. 2, process-1).…”

Section: Fabrication Process and Resultsmentioning

confidence: 99%

“…An X-ray event from the specimen is focused to the TES chip by the polycapillary X-ray optics with a focusing size of roughly 3 mm 2 . Thus, to pack the 8 × 8 TES array onto the 3-mm 2 area, we set the TES size to be 180 μ m square and attached a 120 μ m square gold absorber to the TES pixel [9]. The transition temperature T c was 160 mK, and the rise time constant and the fall time constant were ∼ 1 μ s and ∼ 70 μ s, respectively.…”

Section: Introductionmentioning

confidence: 99%

A Concept Design of TES X-ray Microcalorimeter Array with Different Thickness Absorber Toward the Observation from 50 eV to 15 keV for STEM-EDS

et al. 2020

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We herein report a concept study of a transition edge sensor (TES) X-ray microcalorimeter array with two different thickness absorbers. We developed an energydispersive X-ray spectroscope (EDS) with a 64-pixel TES array and installed it on a scanning transmission electron microscope (STEM) for material analysis. One of the key applications of the proposed system is the microanalysis of astromaterials, for which the relative abundance of light elements such as boron, carbon, and oxygen against silicon are crucial. However, the line sensitivity below ∼ 500 eV for the our STEM TES EDS system was not enough to detect the X-ray from light elements because of the relatively high continuum emission and low detection efficiency, which occurs due to the X-ray window and the optical blocking filters. A simple solution to increase line sensitivity at low energy is the adoption of thin X-ray absorbers that leads to an improvement in the energy resolution. However, doing so causes the sensitivity to decrease for high energy lines. Utilizing the spotsize dependence of the polycapillary X-ray optics on energy, which are used in the STEM TES EDS system, we studied a design in which thin absorbers are distributed on the outer area of detector. We optimized the design using the raytracing analysis of optics. A thin (300 nm) absorber is placed on the 52 outer pixels, while a thick (3.5 μ m) absorber is placed on the central 12 pixels. The thin pixels detect approximately 50-60% of the total counts in 0.1-2 keV, while the central thick pixels detect approximately 50-80% of the total counts in 2-10 keV. We also demonstrated the fabrication process of two-thickness absorber arrays.

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“…1). Moreover, we determined the absorber thickness to satisfy the requirements for STEM described by Muramatsu et al [5]. The Cu absorber takes most of the heat capacity of the TES microcalorimeter.…”

Section: Prototype Designmentioning

confidence: 99%

“…Firstly, the SiN x of the frontside is removed as an alignment mark by reactive ion etching (RIE). The SiN x and SiO 2 of the backside are removed as a membrane pattern by the RIE and the wet etching [5]. The TES is the bilayer of Ti and Au, deposited on SiN x by DC magnetron sputtering [6].…”

Section: Fabrication Of Cu/bi Bilayer Absorber With Electrodepositionmentioning

confidence: 99%

Study of Multilayer X-ray Absorbers to Improve Detection Efficiency of TES X-ray Microcalorimeter Arrays

et al. 2016

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We report the fabrication and evaluation of the Cu/Bi bilayer absorber with electrodeposition. We designed the Cu/Bi absorber to satisfy the requirements for scanning transmission electron microscope (STEM). The residual resistivity ratios of films of Cu and Bi with electrodeposition was 5.91 ± 0.49 and 2.06 ± 0.33, respectively; these values are sufficient for the requirements of STEM. We found that the Cu/Bi bilayer absorber TES microcalorimeter experienced a pulse-shape variation and we considered that these variations were caused by the quality of the contact surface between the absorber and TES. In addition, we examined the structure of the absorber using focus ion beam analysis and STEM. The results suggest that an oxidation between the Cu and seed layer, in which the layer is an electrode for electrodeposition, yielded variations. Moreover, thermal simulation suggests that the thermal conduction between the absorber and TES caused variations. The results of this study will improve the process of Bi electrodeposition.

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Design and Performance of a TES X-ray Microcalorimeter Array for Energy Dispersive Spectroscopy on Scanning Transmission Electron Microscope

Cited by 21 publications

References 7 publications

Common Bias Readout for TES Array on Scanning Transmission Electron Microscope

Common Bias Readout for TES Array on Scanning Transmission Electron Microscope

A Concept Design of TES X-ray Microcalorimeter Array with Different Thickness Absorber Toward the Observation from 50 eV to 15 keV for STEM-EDS

Study of Multilayer X-ray Absorbers to Improve Detection Efficiency of TES X-ray Microcalorimeter Arrays

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