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.

scholarly journals SEM/EDS Analysis of Boron in Waste Glasses with Ultrathin Window Detector and Digital Pulse Processor

1996 ◽  
Vol 54 ◽  
pp. 484-485
Author(s):  
J.S. Luo ◽  
S.F. Wolf ◽  
W.L. Ebert ◽  
J.K. Bates
Keyword(s):  
Detection Efficiency ◽  
X Rays ◽  
Reaction Products ◽  
Glass Corrosion ◽  
Eds Analysis ◽  
Wavelength Dispersive Spectrometry ◽  
Digital Pulse ◽  
High Detection ◽  
High Detection Efficiency ◽  
Glass Analysis

Borosilicate glass has been selected for immobilizing radioactive wastes because of its chemical durability and ability to incorporate many different elements.Boron is an important component in the borosilicate waste glass: its addition facilitates the processibility of glass by lowering its viscosity. In addition, the release of boron is used to measure the corrosion progress during laboratory tests that determine the durability of a glass. Analysis of boron that is present in waste glasses and in the reaction products that form during the reaction of glass is important for understanding the reaction kinetics and mechanism of glass corrosion.Waste glasses have been previously analyzed for B in our laboratory by wavelength-dispersive spectrometry (WDS) in SEM. As can be deduced from Fig. 1, WDS analysis of waste glasses with B concentrations up to 4 wt% yields a line with a slope of 0.4 counts/s/wt%, with a resolution of ˜0.5 wt%. However, EDS is analytically more convenient and advantageous because its high detection efficiency and its ability to simultaneously acquire an entire spectrum. The innovation of the ultra-thin window has made it possible for an EDS to detect soft x-rays, which are absorbed by a normal Be window.

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 Next generation X-ray detectors for in-house XRD

2008 ◽  
Vol 23 (2) ◽  
pp. 101-105 ◽  
Author(s):  
Takeyoshi Taguchi ◽  
Christian Brönnimann ◽  
Eric F. Eikenberry
Keyword(s):  
Generation X ◽  
Dynamic Range ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Photon Counting ◽  
Next Generation ◽  
Large Area ◽  
X Ray ◽  
Array Detectors ◽  
Good Signal

A novel type X-ray detector, called PILATUS, has been developed at the Paul Scherrer Institut in Switzerland during the last decade. PILATUS detectors are two-dimensional hybrid pixel array detectors, which operate in single-photon counting mode. PILATUS detectors feature a very wide dynamic range (1:1 000 000), very short readout time (<3.0 ms), no readout noise, and very high counting rate (>2×106counts/s/pixel). In addition, a lower energy threshold can be set in order to suppress fluorescence background from the sample, thus a very good signal-to-noise ratio is achieved. The combination of these features for area detectors is unique and thus the PILATUS detectors are considered to be the next generation X-ray detectors. The basic building block of all the detectors is the PILATUS module having an active area of 83.8×33.5 mm2. The PILATUS 100K is a complete detector system with one module. PILATUS detector systems can have other configurations, including large area systems consisting of 20 to 60 modules that can cover up to an area of 431×448 mm2. Such large systems are mainly used for macromolecular structure determination, such as protein crystallography and small angle X-ray scattering. The PILATUS 100K detector can be easily adapted to many systems; the single-module detector is integrated to an in-house X-ray diffraction (XRD) system. Examples of XRD measurements with the PILATUS 100K detector are given.

scholarly journals In situtwo-dimensional imaging quick-scanning XAFS with pixel array detector

2011 ◽  
Vol 18 (6) ◽  
pp. 919-922 ◽  
Author(s):  
Hajime Tanida ◽  
Hisao Yamashige ◽  
Yuki Orikasa ◽  
Masatsugu Oishi ◽  
Yu Takanashi ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Low Noise ◽  
Array Detector ◽  
Large Area ◽  
Scanning Method ◽  
Two Dimensional Image ◽  
Pixel Array ◽  
Pixel Array Detector ◽  
Good Signal

Quick-scanning X-ray absorption fine structure (XAFS) measurements were performed in transmission mode using a PILATUS 100K pixel array detector (PAD). The method can display a two-dimensional image for a large area of the order of a centimetre with a spatial resolution of 0.2 mm at each energy point in the XAFS spectrum. The time resolution of the quick-scanning method ranged from 10 s to 1 min per spectrum depending on the energy range. The PAD has a wide dynamic range and low noise, so the obtained spectra have a good signal-to-noise ratio.

SUPERCONDUCTING PROPERTIES OF LuNi2B2C THIN FILMS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2743-2748 ◽  
Author(s):  
G. GRASSANO ◽  
M. R. CIMBERLE ◽  
D. MARRÈ ◽  
I. PALLECCHI ◽  
M. PUTTI ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Careful Study ◽  
X Rays ◽  
Superconducting Properties ◽  
Large Area ◽  
Force Microscopy ◽  
Deposition Parameters ◽  
Wide Range ◽  
Set Up

We present the results of collaboration between the groups of Naples and Genoa Universities/INFM, focused on thin films superconducting borocarbides. In particular a careful study of the deposition of non-magnetic LuNi 2 B 2 C thin films by Pulsed Laser Deposition (PLD) on MgO and other substrates will be presented. While samples with good c-orientation and superconducting properties are obtained in wide range of deposition parameters, in-plane micrometric oriented structures are obtained only in a narrow range of conditions, as evidenced by X-rays measurements and AFM (atomic force microscopy) analyses. A special set-up for the in situ interchanging of shadow masks has been developed in order to deposit the diferent patterned layers and different buffer and/or barrier layers. New results on the temperature dependence of the LuNi 2 B 2 C gap using S/N contact junctions are presented and discussed. The obtained value of the superconducting gap and its temperature dependence agrees very well with the BCS prediction. We present also microwave measurements of the surface impedance performed on large area films obtained by sputtering technique on low loss sapphire substrates. The data confirm the overall BCS-like behavior of these compounds.

Study of the Thermal and Intrinsic Stress of Large Area Diamond Film Prepared by HFCVD

2008 ◽  
Vol 375-376 ◽  
pp. 123-127 ◽  
Author(s):  
Feng Xu ◽  
Dun Wen Zuo ◽  
Wen Zhuang Lu ◽  
Min Wang ◽  
Hai Yu Zhang
Keyword(s):  
Thermal Stress ◽  
Thick Film ◽  
Diamond Film ◽  
Chemical Vapor ◽  
Intrinsic Stress ◽  
Large Area ◽  
Element Analysis ◽  
Fea Model ◽  
Chemical Vapor Deposited ◽  
Set Up

High residual stress that includes thermal and intrinsic stress is an obstacle to the further application of chemical vapor deposited diamond thick film. In this paper, CVD diamond thick film was deposited on silicon substrate by hot filament chemical vapor deposited (HFCVD) system. The finite element analysis (FEA) simulation and experimental research were carried out on the thermal and intrinsic stress of large area diamond thick film. The FEA model is set up to investigate the distribution and magnitude of thermal stress. The intrinsic stress is studied by X-Ray diffraction “sin2ψ” method. The thermal stress and intrinsic stress are both compression stress. Simulation results show the discontinuous sharp of the diamond film result in the stress concentration and low cooling velocity is a good way to reduce thermal stress. The intrinsic stress is correlative with the microstructure and non-diamond component of diamond film. The origin of the intrinsic stress is discussed in detail in this paper.

In Situ Observation of Polytype Switches during SiC PVT Bulk Growth by High Energy X-Ray Diffraction

2009 ◽  
Vol 615-617 ◽  
pp. 23-26 ◽  
Author(s):  
Peter J. Wellmann ◽  
Katja Konias ◽  
Philip Hens ◽  
Rainer Hock ◽  
Andreas Magerl
Keyword(s):  
Signal To Noise Ratio ◽  
High Energy ◽  
In Situ Observation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bulk Growth ◽  
Diffraction Patterns ◽  
Set Up ◽  
Good Signal

This work reports on the in-situ observation of a polytype switch during physical vapor transport (PVT) growth of bulk SiC crystals by x-ray diffraction. A standard PVT reactor for 2” and 3” bulk growth was set up in a high-energy x-ray diffraction lab. Due to the high penetration depth of the high-energy x-ray beam no modification of the PVT reactor was necessary in order to measure Laue diffraction patterns of the growing crystal with good signal to noise ratio. We report for the first time upon the in-situ observation of polytype switching during SiC bulk PVT growth.

scholarly journals Searching for gamma-ray emission from galaxy clusters at low redshift

2019 ◽  
Vol 491 (3) ◽  
pp. 3225-3244 ◽  
Author(s):  
Manuel Colavincenzo ◽  
Xiuhui Tan ◽  
Simone Ammazzalorso ◽  
Stefano Camera ◽  
Marco Regis ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Gamma Ray ◽  
Signal To Noise Ratio ◽  
Galaxy Cluster ◽  
Accurate Estimation ◽  
X Rays ◽  
Diffuse Emission ◽  
Large Area ◽  
Significant Case ◽  
Gamma Ray Emission

ABSTRACT We report the identification of a positive cross-correlation signal between the unresolved gamma-ray emission, measured by the Fermi Large Area Telescope, and four different galaxy cluster catalogues. The selected catalogues peak at low-redshift and span different frequency bands, including infrared, optical, and X-rays. The signal-to-noise ratio of the detected cross-correlation amounts to 3.5 in the most significant case. We investigate and comment about its possible origin, in terms of compact gamma-ray emission from AGNs inside clusters or diffuse emission from the intracluster medium. The analysis has been performed by introducing an accurate estimation of the cross-correlation power-spectrum covariance matrix, built with mock realizations of the gamma and galaxy cluster maps. Different methods to produce the mock realizations starting from the data maps have been investigated and compared, identifying suitable techniques which can be generalized to other cross-correlation studies.

scholarly journals Overcoming detection loss and noise in squeezing-based optical sensing

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Gaetano Frascella ◽  
Sascha Agne ◽  
Farid Ya. Khalili ◽  
Maria V. Chekhova
Keyword(s):  
Shot Noise ◽  
Optical Sensing ◽  
Detection Efficiency ◽  
Signal To Noise Ratio ◽  
Real Life ◽  
Squeezed States ◽  
Squeezed Light ◽  
Noise Limit ◽  
Imaging And Spectroscopy ◽  
Shot Noise Limit

AbstractAmong the known resources of quantum metrology, one of the most practical and efficient is squeezing. Squeezed states of atoms and light improve the sensing of the phase, magnetic field, polarization, mechanical displacement. They promise to considerably increase signal-to-noise ratio in imaging and spectroscopy, and are already used in real-life gravitational-wave detectors. But despite being more robust than other states, they are still very fragile, which narrows the scope of their application. In particular, squeezed states are useless in measurements where the detection is inefficient or the noise is high. Here, we experimentally demonstrate a remedy against loss and noise: strong noiseless amplification before detection. This way, we achieve loss-tolerant operation of an interferometer fed with squeezed and coherent light. With only 50% detection efficiency and with noise exceeding the level of squeezed light more than 50 times, we overcome the shot-noise limit by 6 dB. Sub-shot-noise phase sensitivity survives up to 87% loss. Application of this technique to other types of optical sensing and imaging promises a full use of quantum resources in these fields.

scholarly journals Thermodynamics Controlled Sharp Transformation from InP to GaP Nanowires via Introducing Trace Amount of Gallium

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhenzhen Tian ◽  
Xiaoming Yuan ◽  
Ziran Zhang ◽  
Wuao Jia ◽  
Jian Zhou ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Driving Force ◽  
Chemical Vapor ◽  
Chemical Vapor Deposition Method ◽  
Nanowire Growth ◽  
Calphad Approach ◽  
Deposition Method ◽  
Large Area ◽  
Growth Phenomenon

AbstractGrowth of high-quality III–V nanowires at a low cost for optoelectronic and electronic applications is a long-term pursuit of research. Still, controlled synthesis of III–V nanowires using chemical vapor deposition method is challenge and lack theory guidance. Here, we show the growth of InP and GaP nanowires in a large area with a high density using a vacuum chemical vapor deposition method. It is revealed that high growth temperature is required to avoid oxide formation and increase the crystal purity of InP nanowires. Introduction of a small amount of Ga into the reactor leads to the formation of GaP nanowires instead of ternary InGaP nanowires. Thermodynamic calculation within the calculation of phase diagrams (CALPHAD) approach is applied to explain this novel growth phenomenon. Composition and driving force calculations of the solidification process demonstrate that only 1 at.% of Ga in the catalyst is enough to tune the nanowire formation from InP to GaP, since GaP nucleation shows a much larger driving force. The combined thermodynamic studies together with III–V nanowire growth studies provide an excellent example to guide the nanowire growth.

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