XPAD X-ray hybrid pixel detector for charge density quality diffracted intensities on laboratory equipment

2014 ◽  
Vol 70 (5) ◽  
pp. 783-791 ◽  
Author(s):  
Emmanuel Wenger ◽  
Slimane Dahaoui ◽  
Paul Alle ◽  
Pascal Parois ◽  
Cyril Palin ◽  
...  
Keyword(s):  
Charge Density ◽  
Single Photon ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Low Noise ◽  
Quality Data ◽  
High Signal ◽  
Pixel Detector ◽  
Laboratory Equipment ◽  
X Ray

The new generation of X-ray detectors, the hybrid pixel area detectors or `pixel detectors', is based on direct detection and single-photon counting processes. A large linearity range, high dynamic and extremely low noise leading to an unprecedented high signal-to-noise ratio, fast readout time (high frame rates) and an electronic shutter are among their intrinsic characteristics which render them very attractive. First used on synchrotron beamlines, these detectors are also promising in the laboratory, in particular for pump-probe or quasi-static experiments and accurate electron density measurements, as explained in this paper. An original laboratory diffractometer made from a Nonius Mach3 goniometer equipped with an Incoatec Mo microsource and an XPAD pixel area detector has been developed at the CRM2 laboratory. MoKα accurate charge density quality data up to 1.21 Å−1resolution have been collected on a sodium nitroprusside crystal using this home-made diffractometer. Data quality for charge density analysis based on multipolar modelling are discussed in this paper. Deformation electron densities are compared to those already published (based on data collected with CCD APEXII and CAD4 diffractometers).

Experimental Characterization of APD and Design of Quenching Circuit for Single-Photon Detection

2012 ◽  
Vol 246-247 ◽  
pp. 273-278 ◽  
Author(s):  
Hua Lü
Keyword(s):  
Integrated Circuit ◽  
Single Photon ◽  
Signal To Noise Ratio ◽  
Avalanche Photodiode ◽  
Low Noise ◽  
High Signal ◽  
Single Photon Detection ◽  
Single Photon Detector ◽  
Photon Detection ◽  
Geiger Mode

In this paper, we experimentally characterize the Inga As/Imp avalanche photodiode (APD), which is working in Geiger mode, so as to choose the single photon detector for quantum communication. Due to the fact that bias of APD tends to be flat after avalanche, we first adopt the methodology of passive quenching to determine dark breakdown voltage. Experiment results indicate that temperature reduction will widen the optimal operating region and increase the optimal multiplication; therefore APD will be more sensitive. Epitaxial APD is the best choice for single-photon detection among the APDs we have tested for its low noise level and high signal-to-noise ratio (SNR). Finally, we design a mixed passive-active quenching integrated circuit with gate control, which is quick with the quenching time of about 25ns and has controllable dead time with minimum of about 60ns.

scholarly journals Synchrotron X-ray diffraction experiments with a prototype hybrid pixel detector

2011 ◽  
Vol 45 (1) ◽  
pp. 38-47 ◽  
Author(s):  
C. Le Bourlot ◽  
P. Landois ◽  
S. Djaziri ◽  
P.-O. Renault ◽  
E. Le Bourhis ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
High Dynamic Range ◽  
High Signal ◽  
Pixel Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Area Detector ◽  
Duplex Steel ◽  
Scientific Results

A prototype X-ray pixel area detector (XPAD3.1) has been used for X-ray diffraction experiments with synchrotron radiation. The characteristics of this detector are very attractive in terms of fast readout time, high dynamic range and high signal-to-noise ratio. The prototype XPAD3.1 enabled various diffraction experiments to be performed at different energies, sample-to-detector distances and detector angles with respect to the direct beam, yet it was necessary to perform corrections on the diffraction images according to the type of experiment. This paper is focused on calibration and correction procedures to obtain high-quality scientific results specifically developed in the context of three different experiments, namely mechanical characterization of nanostructured multilayers, elastic–plastic deformation of duplex steel and growth of carbon nanotubes.

Subpixel resolution in CdTe Timepix3 pixel detectors

2018 ◽  
Vol 25 (6) ◽  
pp. 1650-1657 ◽  
Author(s):  
Mohamad Khalil ◽  
Erik Schou Dreier ◽  
Jan Kehres ◽  
Jan Jakubek ◽  
Ulrik Lund Olsen
Keyword(s):  
Single Photon ◽  
Weighted Average ◽  
European Synchrotron Radiation Facility ◽  
Time Of Arrival ◽  
Pixel Detector ◽  
Step Size ◽  
X Ray ◽  
Pixel Detectors ◽  
Individual Photon ◽  
Subpixel Resolution

Timepix3 (256 × 256 pixels with a pitch of 55 µm) is a hybrid-pixel-detector readout chip that implements a data-driven architecture and is capable of simultaneous time-of-arrival (ToA) and energy (ToT: time-over-threshold) measurements. The ToA information allows the unambiguous identification of pixel clusters belonging to the same X-ray interaction, which allows for full one-by-one detection of photons. The weighted mean of the pixel clusters can be used to measure the subpixel position of an X-ray interaction. An experiment was performed at the European Synchrotron Radiation Facility in Grenoble, France, using a 5 µm × 5 µm pencil beam to scan a CdTe-ADVAPIX-Timepix3 pixel (55 µm × 55 µm) at 8 × 8 matrix positions with a step size of 5 µm. The head-on scan was carried out at four monochromatic energies: 24, 35, 70 and 120 keV. The subpixel position of every single photon in the beam was constructed using the weighted average of the charge spread of single interactions. Then the subpixel position of the total beam was found by calculating the mean position of all photons. This was carried out for all points in the 8 × 8 matrix of beam positions within a single pixel. The optimum conditions for the subpixel measurements are presented with regards to the cluster sizes and beam subpixel position, and the improvement of this technique is evaluated (using the charge sharing of each individual photon to achieve subpixel resolution) versus alternative techniques which compare the intensity ratio between pixels. The best result is achieved at 120 keV, where a beam step of 4.4 µm ± 0.86 µm was measured.

scholarly journals Testing the accuracy of reflection-based supermassive black hole spin measurements in AGN

2018 ◽  
Vol 614 ◽  
pp. A44 ◽  
Author(s):  
E. S. Kammoun ◽  
E. Nardini ◽  
G. Risaliti
Keyword(s):  
Thermal Emission ◽  
Signal To Noise Ratio ◽  
Galactic Nuclei ◽  
Relativistic Effects ◽  
High Signal ◽  
X Ray ◽  
Multiple Components ◽  
Spin Parameter ◽  
Partial Covering ◽  
Spin Measurements

Context. X-ray reflection is a very powerful method to assess the spin of supermassive black holes (SMBHs) in active galactic nuclei (AGN), yet this technique is not universally accepted. Indeed, complex reprocessing (absorption, scattering) of the intrinsic spectra along the line of sight can mimic the relativistic effects on which the spin measure is based. Aims. In this work, we test the reliability of SMBH spin measurements that can currently be achieved through the simulations of high-quality XMM-Newton and NuSTAR spectra. Methods. Each member of our group simulated ten spectra with multiple components that are typically seen in AGN, such as warm and (partial-covering) neutral absorbers, relativistic and distant reflection, and thermal emission. The resulting spectra were blindly analysed by the other two members. Results. Out of the 60 fits, 42 turn out to be physically accurate when compared to the input model. The SMBH spin is retrieved with success in 31 cases, some of which (9) are even found among formally inaccurate fits (although with looser constraints). We show that, at the high signal-to-noise ratio assumed in our simulations, neither the complexity of the multi-layer, partial-covering absorber nor the input value of the spin are the major drivers of our results. The height of the X-ray source (in a lamp-post geometry) instead plays a crucial role in recovering the spin. In particular, a success rate of 16 out of 16 is found among the accurate fits for a dimensionless spin parameter larger than 0.8 and a lamp-post height lower than five gravitational radii.

Observations of TiO2 Surfaces Using Totally Reflected X-ray In-plane Diffraction Under UV Irradiation

2002 ◽  
Vol 751 ◽  
Author(s):  
T. Horiuchi ◽  
H. Ochi ◽  
K. Kaisei ◽  
K. Ishida ◽  
K. Matsushige
Keyword(s):  
Uv Irradiation ◽  
Uv Light ◽  
Plane Surface ◽  
Signal To Noise Ratio ◽  
High Surface ◽  
Ultra Violet ◽  
High Signal ◽  
X Ray ◽  
Force Microscopy ◽  
Catalytic Activities

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.

scholarly journals The time-resolved hard X-ray diffraction endstation KMC-3 XPP at BESSY II

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Matthias Rössle ◽  
Wolfram Leitenberger ◽  
Matthias Reinhardt ◽  
Azize Koç ◽  
Jan Pudell ◽  
...  
Keyword(s):  
Storage Ring ◽  
Single Photon ◽  
Laser System ◽  
High Vacuum ◽  
Laser Pulses ◽  
Pixel Detector ◽  
X Ray Diffraction ◽  
Optical Pump ◽  
Time Resolved ◽  
X Ray

The time-resolved hard X-ray diffraction endstation KMC-3 XPP for optical pump/X-ray probe experiments at the electron storage ring BESSY II is dedicated to investigating the structural response of thin film samples and heterostructures after their excitation with ultrashort laser pulses and/or electric field pulses. It enables experiments with access to symmetric and asymmetric Bragg reflections via a four-circle diffractometer and it is possible to keep the sample in high vacuum and vary the sample temperature between ∼15 K and 350 K. The femtosecond laser system permanently installed at the beamline allows for optical excitation of the sample at 1028 nm. A non-linear optical setup enables the sample excitation also at 514 nm and 343 nm. A time-resolution of 17 ps is achieved with the `low-α' operation mode of the storage ring and an electronic variation of the delay between optical pump and hard X-ray probe pulse conveniently accesses picosecond to microsecond timescales. Direct time-resolved detection of the diffracted hard X-ray synchrotron pulses use a gated area pixel detector or a fast point detector in single photon counting mode. The range of experiments that are reliably conducted at the endstation and that detect structural dynamics of samples excited by laser pulses or electric fields are presented.

Internally Modulated Chirped Pulse Based Direct Detection Type φ-OTDR System with High Signal-to-Noise Ratio and Low Cost

2019 ◽  
Vol 46 (8) ◽  
pp. 0806003
Author(s):  
李鲁川 Luchuan Li ◽  
卢斌 Bin Lu ◽  
王校 Xiao Wang ◽  
梁嘉靖 Jiajing Liang ◽  
郑汉荣 Hanrong Zheng ◽  
...  
Keyword(s):  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
High Signal ◽  
Signal To Noise ◽  
Chirped Pulse ◽  
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.

Single photon imaging X-ray spectrometers using low noise current preamplifiers with dc voltage bias

1997 ◽  
Vol 7 (2) ◽  
pp. 3383-3386 ◽  
Author(s):  
S. Friedrich ◽  
K. Segall ◽  
M.C. Gaidis ◽  
C.M. Wilson ◽  
D.E. Prober ◽  
...  
Keyword(s):  
Single Photon ◽  
Low Noise ◽  
Dc Voltage ◽  
X Ray ◽  
Noise Current ◽  
Voltage Bias ◽  
Photon Imaging

Effects of Very High Neutron Fluence Irradiation on p+n Junction 4H-SiC Diodes

2007 ◽  
Vol 556-557 ◽  
pp. 917-920 ◽  
Author(s):  
Francesco Moscatelli ◽  
Andrea Scorzoni ◽  
Antonella Poggi ◽  
Mara Passini ◽  
Giulio Pizzocchero ◽  
...  
Keyword(s):  
Leakage Current ◽  
Leakage Current Density ◽  
Current Density ◽  
Reverse Bias ◽  
Neutron Fluence ◽  
Signal To Noise Ratio ◽  
Reverse Current ◽  
Low Noise ◽  
High Signal ◽  
Very High

In this work we analyzed the radiation hardness of SiC p+n diodes after very high 1 MeV neutron fluence. The diode structure is based on a p+ emitter ion implanted in n-type epilayer with thickness equal to 5 %m and donor doping ND = 3×1015 cm-3. Before irradiation, the average leakage current density at 100 V reverse bias was of the order of 3 nA/cm2. These devices were irradiated at four different fluence values, logarithmically distributed in the range 1014-1016 (1 MeV) neutrons/cm2. After irradiation the epilayer material became more resistive, as indicated by the reduction of the forward and reverse current density at a given voltage. In particular, after a neutron fluence of 1×1014 n/cm2 the epilayer active doping concentration decreased to 1.5×1015 cm-3. After irradiation at 1016 n/cm2, i.e. the highest fluence value, the average leakage current density at 100 V reverse bias decreased to values of the order of 0.1 nA/cm2. This very low noise even after very high fluence is very important to obtain a high signal to noise ratio even at room temperature.

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