X-Ray Detectors Based on “Thick” a-Si:H Layers Deposited by the VHF-GD Process

1992 ◽  
Vol 258 ◽  
Author(s):  
P. Chabloz ◽  
H. Keppner ◽  
V. Baertschi ◽  
A. Shah ◽  
D. Chatellard ◽  
...  
Keyword(s):  
Solar Cell ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Reverse Current ◽  
High Energy ◽  
High Deposition Rate ◽  
X Rays ◽  
Cell Type ◽  
Large Area ◽  
X Ray

ABSTRACTIn spite of its low absorption coefficient for X-rays, amorphous Silicon can be an interesting alternative approach for X-ray detection because of its low cost, its potential for large-area deposition and the possibility to deposit on a curved surface. For this application, basically two approaches have been proposed up to now: either a thick solar cell type n-i-p structure (the i-layer as to be sufficiently thick i.e typically 50 μm or more), or a normal solar cell type n-i-p structure (with a relatively thin i-layer, i.e (typically 1 to 2 μm) together with a fluorescent layer emitting visible light composed e.g. of CsJ. In this paper, we present first results of a X-ray detectors with thick i-layers (15 to 100 μm) prepared by the high deposition rate VHF-GD technique introduced at our laboratory. Detectors with low leakage currents (<4nA/cm2) under high reverse bias voltages (about 100 V) could be fabricated at rates as high as 22 Å/s. As substrates, aluminium as well as TCO-coated glass substrates were used. The detectors have a n-i-p structure, where highly conductive (100 S/cm) n-doped μc-Si:H was first deposited. For the substrate preparation, a high energy Ar plasma was applied before the first deposition step; in this way excellent sticking conditions could be achieved, although in the thicker detectors considerable curvature due to the internal mechanical stress could be observed. A medical X-ray radiation source was used, where the detector was exposed to a continuous X-ray spectrum at acceleration voltages between 80 kV and 240 kV. The paper presents measurements on the linearity of the detector, as well as on the value of the reverse current in the dark, which must be as small as possible to have the best signal to noise ratio.

scholarly journals Imaging in Hard X-ray Astronomy

2003 ◽  
Vol 214 ◽  
pp. 70-83 ◽  
Author(s):  
T. P. Li
Keyword(s):  
Gamma Ray ◽  
Signal To Noise Ratio ◽  
High Energy ◽  
High Signal ◽  
Wide Field ◽  
X Rays ◽  
X Ray ◽  
Energy Gamma ◽  
High Resolution Images ◽  
Energy Processes

The energy range of hard X-rays is a key waveband to the study of high energy processes in celestial objects, but still remains poorly explored. In contrast to direct imaging methods used in the low energy X-ray and high energy gamma-ray bands, currently imaging in the hard X-ray band is mainly achieved through various modulation techniques. A new inversion technique, the direct demodulation method, has been developed since early 90s. with this technique, wide field and high resolution images can be derived from scanning data of a simple collimated detector. The feasibility of this technique has been confirmed by experiment, balloon-borne observation and analyzing simulated and real astronomical data. Based the development of methodology and instrumentation, a high energy astrophysics mission – Hard X-ray Modulation Telescope (HXMT) has been proposed and selected in China for a four-year Phase-A study. The main scientific objectives are a full-sky hard X-ray (20–200 keV) imaging survey and high signal-to-noise ratio timing studies of high energy sources.

scholarly journals Development of STJ as a New X-Ray Detector

1998 ◽  
Vol 188 ◽  
pp. 335-336
Author(s):  
N. Y. Yamasaki ◽  
T. Ohashi ◽  
K. Kikuchi ◽  
H. Miyazaki ◽  
E. Rokutanda ◽  
...  
Keyword(s):  
Energy Resolution ◽  
Effective Area ◽  
High Energy ◽  
High Energy Resolution ◽  
X Rays ◽  
Large Area ◽  
Position Resolution ◽  
X Ray ◽  
Plane Detector ◽  
Nippon Steel Corporation

STJs are promising X-ray detectors as high energy resolution spectrometers due to the small excitation energy to break the Cooper pairs to product detectable electrons. The expected energy resolution is about 5 eV for a 6 keV incident X-rays (see review by Kraus et al. and Esposito et al.). We have developed a large area (178 × 178μm2) Nb/Al/AlOX/Al/Nb STJs (Kurakado et al. 1993) and series-connected STJs with a position resolution of 35μm for α particles (Kurakado 1997) at Nippon Steel Corporation. As a focal plane detector in future X-ray missions, we are developing STJs whose targert characteristics are; an energy resolution of 20 eV at 6keV, an effective area of 1 cm2, and position resolution of 100μm.

Preparation of CuIn(SxSe1–x)2 thin films with tunable band gap by controlling sulfurization temperature of CuInSe2

2010 ◽  
Vol 25 (12) ◽  
pp. 2426-2429 ◽  
Author(s):  
Guangjun Wang ◽  
Gang Cheng ◽  
Binbin Hu ◽  
Xiaoli Wang ◽  
Shaoming Wan ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Band Gap ◽  
Low Cost ◽  
Chalcopyrite Structure ◽  
X Ray Diffraction ◽  
Large Area ◽  
X Ray ◽  
Sulfurization Temperature ◽  
Tunable Band Gap

In this paper, polycrystalline CuIn(SxSe1–x)2 thin films with tunable x and Eg (band gap) values were prepared by controlling the sulfurization temperature (T) of CuInSe2 thin films. X-ray diffraction indicated the CuIn(SxSe1–x)2 films exhibited a homogeneous chalcopyrite structure. When T increases from 150 to 500 °C, x increases from 0 to 1, and Eg increases from 0.96 to 1.43 eV. The relations between x and Eg and the sulfurization process of CuIn(SxSe1–x)2 thin films have been discussed. This work provides an easy and low-cost technique for preparing large area absorber layers of solar cell with tunable Eg.

scholarly journals LECX: a cubesat experiment to detect and localize cosmic explosions in hard X-rays

2020 ◽  
Vol 493 (4) ◽  
pp. 4852-4860
Author(s):  
J Braga ◽  
O S C Durão ◽  
M Castro ◽  
F D’Amico ◽  
P E Stecchini ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Low Cost ◽  
Cost Effective ◽  
High Energy ◽  
Compact Objects ◽  
X Rays ◽  
X Ray ◽  
Competitive Capabilities ◽  
Cosmic Explosions

ABSTRACT With the advent of the nanosat/cubesat revolution, new opportunities have appeared to develop and launch small (∼1000 cm3), low-cost (∼US$ 1M) experiments in space in very short time frames (∼2  yr). In the field of high-energy astrophysics, in particular, it is a considerable challenge to design instruments with compelling science and competitive capabilities that can fit in very small satellite buses, such as a cubesat platform, and operate them with very limited resources. Here, we describe a hard X-ray (30–200 keV) experiment, LECX (‘Localizador de Explosões Cósmicas de Raios X’ – Locator of X-Ray Cosmic Explosions), that is capable of detecting and localizing within a few degrees events like gamma-ray bursts and other explosive phenomena in a 2U-cubesat platform, at a rate of ∼5 events per year. In the current gravitational wave era of astronomy, a constellation or swarm of small spacecraft carrying instruments such as LECX can be a very cost-effective way to search for electromagnetic counterparts of gravitational wave events produced by the coalescence of compact objects.

scholarly journals High Energy Radiation from Spider Pulsars

Galaxies ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 93 ◽  
Author(s):  
Chung Yue Hui ◽  
Kwan Lok Li
Keyword(s):  
High Energy ◽  
X Rays ◽  
The Novel ◽  
Large Area ◽  
High Energy Radiation ◽  
X Ray ◽  
Compact Binaries ◽  
Low Mass ◽  
Γ Rays ◽  
Γ Ray

The population of millisecond pulsars (MSPs) has been expanded considerably in the last decade. Not only is their number increasing, but also various classes of them have been revealed. Among different classes of MSPs, the behaviours of black widows and redbacks are particularly interesting. These systems consist of an MSP and a low-mass companion star in compact binaries with an orbital period of less than a day. In this article, we give an overview of the high energy nature of these two classes of MSPs. Updated catalogues of black widows and redbacks are presented and their X-ray/ γ -ray properties are reviewed. Besides the overview, using the most updated eight-year Fermi Large Area Telescope point source catalog, we have compared the γ -ray properties of these two MSP classes. The results suggest that the X-rays and γ -rays observed from these MSPs originate from different mechanisms. Lastly, we will also mention the future prospects of studying these spider pulsars with the novel methodologies as well as upcoming observing facilities.

Miniature diamond anvils for X-ray Raman scattering spectroscopy experiments at high pressure

2017 ◽  
Vol 24 (1) ◽  
pp. 276-282 ◽  
Author(s):  
Sylvain Petitgirard ◽  
Georg Spiekermann ◽  
Christopher Weis ◽  
Christoph Sahle ◽  
Christian Sternemann ◽  
...  
Keyword(s):  
High Pressure ◽  
Raman Scattering ◽  
Signal To Noise Ratio ◽  
High Energy ◽  
X Rays ◽  
Signal To Noise ◽  
X Ray ◽  
Custom Made ◽  
Diamond Anvils ◽  
Noise Ratio

X-ray Raman scattering (XRS) spectroscopy is an inelastic scattering method that uses hard X-rays of the order of 10 keV to measure energy-loss spectra at absorption edges of light elements (Si, Mg, Oetc.), with an energy resolution below 1 eV. The high-energy X-rays employed with this technique can penetrate thick or dense sample containers such as the diamond anvils employed in high-pressure cells. Here, we describe the use of custom-made conical miniature diamond anvils of less than 500 µm thickness which allow pressure generation of up to 70 GPa. This set-up overcomes the limitations of the XRS technique in very high-pressure measurements (>10 GPa) by drastically improving the signal-to-noise ratio. The conical shape of the base of the diamonds gives a 70° opening angle, enabling measurements in both low- and high-angle scattering geometry. This reduction of the diamond thickness to one-third of the classical diamond anvils considerably lowers the attenuation of the incoming and the scattered beams and thus enhances the signal-to-noise ratio significantly. A further improvement of the signal-to-background ratio is obtained by a recess of ∼20 µm that is milled in the culet of the miniature anvils. This recess increases the sample scattering volume by a factor of three at a pressure of 60 GPa. Examples of X-ray Raman spectra collected at the OK-edge and SiL-edge in SiO2glass at high pressures up to 47 GPa demonstrate the significant improvement and potential for spectroscopic studies of low-Zelements at high pressure.

The Basic Physical Principles of Ion, Electron, and X-Ray Detectors and Their Application to Microanalysis

1985 ◽  
Vol 43 ◽  
pp. 154-157
Author(s):  
A.J. Tousimis
Keyword(s):  
Ion Beam ◽  
Depth Resolution ◽  
Sample Surface ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Electrons And Ions ◽  
Spatial Depth ◽  
Minimum Surface Area ◽  
Physical Principles

An integral and of prime importance of any microtopography and microanalysis instrument system is its electron, x-ray and ion detector(s). The resolution and sensitivity of the electron microscope (TEM, SEM, STEM) and microanalyzers (SIMS and electron probe x-ray microanalyzers) are closely related to those of the sensing and recording devices incorporated with them.Table I lists characteristic sensitivities, minimum surface area and depth analyzed by various methods. Smaller ion, electron and x-ray beam diameters than those listed, are possible with currently available electromagnetic or electrostatic columns. Therefore, improvements in sensitivity and spatial/depth resolution of microanalysis will follow that of the detectors. In most of these methods, the sample surface is subjected to a stationary, line or raster scanning photon, electron or ion beam. The resultant radiation: photons (low energy) or high energy (x-rays), electrons and ions are detected and analyzed.

scholarly journals From Femtoseconds to Hours–Measuring Dynamics over 18 Orders of Magnitude with Coherent X-rays

2021 ◽  
Vol 11 (13) ◽  
pp. 6179
Author(s):  
Felix Lehmkühler ◽  
Wojciech Roseker ◽  
Gerhard Grübel
Keyword(s):  
Time Scales ◽  
Free Electron Laser ◽  
Photon Correlation Spectroscopy ◽  
Signal To Noise Ratio ◽  
Coherent Scattering ◽  
Correlation Spectroscopy ◽  
X Rays ◽  
Photon Correlation ◽  
X Ray ◽  
Scattering Technique

X-ray photon correlation spectroscopy (XPCS) enables the study of sample dynamics between micrometer and atomic length scales. As a coherent scattering technique, it benefits from the increased brilliance of the next-generation synchrotron radiation and Free-Electron Laser (FEL) sources. In this article, we will introduce the XPCS concepts and review the latest developments of XPCS with special attention on the extension of accessible time scales to sub-μs and the application of XPCS at FELs. Furthermore, we will discuss future opportunities of XPCS and the related technique X-ray speckle visibility spectroscopy (XSVS) at new X-ray sources. Due to its particular signal-to-noise ratio, the time scales accessible by XPCS scale with the square of the coherent flux, allowing to dramatically extend its applications. This will soon enable studies over more than 18 orders of magnitude in time by XPCS and XSVS.

scholarly journals A large area diamond-based beam tagging hodoscope for ion therapy monitoring

2018 ◽  
Vol 170 ◽  
pp. 09005 ◽  
Author(s):  
M.-L. Gallin-Martel ◽  
L. Abbassi ◽  
A. Bes ◽  
G. Bosson ◽  
J. Collot ◽  
...  
Keyword(s):  
Detection Efficiency ◽  
Signal To Noise Ratio ◽  
Therapy Monitoring ◽  
Chemical Vapor ◽  
X Rays ◽  
Reaction Products ◽  
Large Area ◽  
Position Measurement ◽  
Set Up ◽  
Good Signal

The MoniDiam project is part of the French national collaboration CLaRyS (Contrôle en Ligne de l’hAdronthérapie par RaYonnements Secondaires) for on-line monitoring of hadron therapy. It relies on the imaging of nuclear reaction products that is related to the ion range. The goal here is to provide large area beam detectors with a high detection efficiency for carbon or proton beams giving time and position measurement at 100 MHz count rates (beam tagging hodoscope). High radiation hardness and intrinsic electronic properties make diamonds reliable and very fast detectors with a good signal to noise ratio. Commercial Chemical Vapor Deposited (CVD) poly-crystalline, heteroepitaxial and monocrystalline diamonds were studied. Their applicability as a particle detector was investigated using α and β radioactive sources, 95 MeV/u carbon ion beams at GANIL and 8.5 keV X-ray photon bunches from ESRF. This facility offers the unique capability of providing a focused (~1 μm) beam in bunches of 100 ps duration, with an almost uniform energy deposition in the irradiated detector volume, therefore mimicking the interaction of single ions. A signal rise time resolution ranging from 20 to 90 ps rms and an energy resolution of 7 to 9% were measured using diamonds with aluminum disk shaped surface metallization. This enabled us to conclude that polycrystalline CVD diamond detectors are good candidates for our beam tagging hodoscope development. Recently, double-side stripped metallized diamonds were tested using the XBIC (X Rays Beam Induced Current) set-up of the ID21 beamline at ESRF which permits us to evaluate the capability of diamond to be used as position sensitive detector. The final detector will consist in a mosaic arrangement of double-side stripped diamond sensors read out by a dedicated fast-integrated electronics of several hundreds of channels.

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