Improvements of a-Si:H/CsI(TI) X-RAY Detectors for Radiation Monitoring

1993 ◽  
Vol 302 ◽  
Author(s):  
C. Manfredotti ◽  
F. Fizzotti ◽  
M. Boero ◽  
F. Cannistraci ◽  
E. Vittone ◽  
...  
Keyword(s):  
Experimental Data ◽  
Dark Current ◽  
Radiation Monitoring ◽  
X Rays ◽  
Exposure Rate ◽  
Good Sensitivity ◽  
X Ray ◽  
Dose Rates ◽  
Photovoltaic Mode ◽  
Light Generation

ABSTRACTPhotosensitive a-Si:H p-i-n diodes, working in photovoltaic mode, have been coupled to CsI(T1) scintillators for dosimetry applications to X-ray monitoring in the energy range from 50 keV up to 15 MeV. A “mesa” approach for p-i-n diodes has been adopted both in order to better define the geometry and to obtain very low dark current. In order to optimize the geometry, a computer program has been created which simulates light generation in the scintillator, the collection by the detector and the photovoltaic current obtained as a function of exposure rate.Measurements have been carried out in the X-rays energy ranges 50-240 keV, at 6MeV and at 15 MeV. Detectors are linear in response and shows a good sensitivity, with the capability of measuring dose rates as low as 60 mR/h.The agreement between experimental data and simulation outputs can be considered good.

Wave propagation and focusing of soft X-rays by spherical bent microchannel plates

2021 ◽  
Vol 28 (2) ◽  
pp. 383-391
Author(s):  
M. I. Mazuritskiy ◽  
A. M. Lerer ◽  
A. Marcelli ◽  
S. B. Dabagov ◽  
M. Coreno ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wave Propagation ◽  
Angular Distribution ◽  
X Rays ◽  
X Ray ◽  
Wave Approximation ◽  
Microchannel Plates ◽  
Radiation Sources ◽  
Focus Spot ◽  
Focusing Properties

Synchrotron radiation sources have been used to study the focusing properties and angular distribution of X-ray radiation at the exit of spherically bent microchannel plates (MCPs). In this contribution it is shown how soft X-ray radiation at energies up to 1.5 keV can be focused by spherically bent MCPs with curvature radii R of 30 mm and 50 mm. For these devices, a focus spot is detectable at a distance between the detector and the MCP of less than R/2, with a maximum focusing efficiency up to 23% of the flux illuminating the MCP. The soft X-ray radiation collected at the exit of microchannels of spherically bent MCPs are analyzed in the framework of a wave approximation. A theoretical model for the wave propagation of radiation through MCPs has been successfully introduced to explain the experimental results. Experimental data and simulations of propagating radiation represent a clear confirmation of the wave channeling phenomenon for the radiation in spherically bent MCPs.

Recent Developments in Fluorescent X-Ray Spectrographic-Absorptiometric Analyses of Mineral Systems

1958 ◽  
Vol 2 ◽  
pp. 303-312 ◽  
Author(s):  
Merlyn L. Salmon
Keyword(s):  
Experimental Data ◽  
Radiation Absorption ◽  
X Rays ◽  
X Ray ◽  
Practical Applications ◽  
Denver Research Institute ◽  
Mineral Sample ◽  
Recent Developments ◽  
Mechanical Factors ◽  
Research Institute

AbstractFluorescent x-ray speorographic studies of mineral systems were begun in the Metallurgy Division of the Denver Research Institute in 1953. These studies were concerned with several techniques but the primary research emphasis was placed on a method involving conjunctive analyses by monochromatic x-ray absorptiometry and fluorescent x-ray spectrography.Experimental data for mineral systems with wide variations in matrix compositions exhibit departures from simple calibration curves relating intensity and concentration for an element in a series of samples analyzed by simple fluorescent x-ray spectrographic procedures.Absorptiometric measurements are made with a thin layer of the mineral sample as an absorption filter for the monochromatic x-rays emitted by the element in question. The results of these measurements provide information for improvement of the simple correlation of intensity and concentration by manipulation of the experimental data with various operations based on Beer's law of radiation absorption.The results of work at the Denver Research Institute indicated the feasibility of the fluorescent x-ray spectrographic-absorptiometric method and the current work is an extension of the study of basic fundamentals, mechanical factors and practical applications of the technique.

Hydration Phenomena in a Concentrated Aqueous Solution of Ce(NO3)3. X-ray Diffraction and Raman Spectroscopy

1983 ◽  
Vol 38 (5) ◽  
pp. 533-539 ◽  
Author(s):  
R. Caminiti ◽  
P. Cucca ◽  
A. D′Andrea
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Raman Spectroscopy ◽  
Correlation Function ◽  
Hydration Shell ◽  
X Rays ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Correlation ◽  
Good Agreement

The scattering of X-rays from a concentrated Ce(NO3)3 aqueous solution has been measured and analyzed. The experimental correlation function appears to be mainly characterized by the hydration of the cation: peaks at about 2.55 and 4.65 Å. Good agreement with experimental data is achieved through a model in which the Ce(III) ions have a first and a second hydration shell and also the nitrate group is considered hydrated. Complex formation between cation and anion is confirmed by using Raman spectroscopy.

scholarly journals Theoretical and experimental studies of material radiative properties and their applications to laser and heavy ion inertial fusion

2011 ◽  
Vol 29 (1) ◽  
pp. 69-80 ◽  
Author(s):  
N. Yu. Orlov ◽  
O.B. Denisov ◽  
O.N. Rosmej ◽  
D. Schäfer ◽  
Th. Nisius ◽  
...  
Keyword(s):  
Experimental Data ◽  
Experimental Studies ◽  
Radiation Efficiency ◽  
Radiative Properties ◽  
Wall Material ◽  
Inertial Fusion ◽  
X Rays ◽  
X Ray ◽  
Wide Range ◽  
X Ray Absorption

AbstractTheoretical and experimental studies of radiative properties of substances heated by pulsed current devises or lasers and used as X-ray sources have been carried out depending on plasma conditions, and specific spectra of X-ray absorption and radiation for different materials have been calculated. Important features of the theoretical model, known as the ion model of plasma, are discussed. This model can be applied for calculations of the radiative properties of complex materials over a wide range of plasma parameters. For purposes of indirect-driven inertial fusion based on the hohlraum concept, an optimization method is used for the selection of an effective complex hohlraum wall material, which provides high radiation efficiency at laser interaction with the wall. The radiation efficiency of the resulting material is compared with the efficiency of other composite materials that have previously been evaluated theoretically. A similar theoretical study is performed for the optically thin X-pinch plasma produced by exploding wires. Theoretical estimations of radiative efficiency are compared with experimental data that have been obtained from measurements of X-pinch radiation energy yield using two exploding wire materials, NiCr and Alloy 188. It is shown that the theoretical results agree well with the experimental data. A symmetric multilayer X-pinch, where W and Mo wires are used, is as well considered. The theoretical explanation of experimental phenomena is discussed based on the W and Mo radiative spectra. The ion model was as well applied for interpretation of experimental results on opacities of CHO-plasma obtained via indirect heating of low density polymer layers by means of soft X-rays. The new diagnostics method based on the deformation of the of the Carbon absorption K-edge when foam layer is heated to plasma is discussed. The spectral coefficients for X-ray absorption in CHO-plasma are calculated in the photon energy region around the Carbon K-edge for different plasma temperatures and mean foam density. In this case, the Carbon K-edge position on the energy scale can be used for plasma temperature diagnostic.

scholarly journals The anisotropy in the optical constants of quartz crystals for soft X-rays

2021 ◽  
Vol 54 (2) ◽  
Author(s):  
A. Andrle ◽  
P. Hönicke ◽  
J. Vinson ◽  
R. Quintanilha ◽  
Q. Saadeh ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Experimental Data ◽  
Refractive Index ◽  
Optical Constants ◽  
Quartz Crystal ◽  
Crystal Surface ◽  
X Rays ◽  
Data Set ◽  
Quartz Crystals ◽  
X Ray

The refractive index of a y-cut SiO2 crystal surface is reconstructed from orientation-dependent soft X-ray reflectometry measurements in the energy range from 45 to 620 eV. Owing to the anisotropy of the crystal structure in the (100) and (001) directions, a significant deviation of the measured reflectance at the Si L 2,3 and O K absorption edges is observed. The anisotropy in the optical constants reconstructed from these data is also confirmed by ab initio Bethe–Salpeter equation calculations for the O K edge. This new experimental data set expands the existing literature data for quartz crystal optical constants significantly, particularly in the near-edge regions.

scholarly journals Parasitic Conduction Response to X-ray Radiation in Unstrained and Strained Triple-Gate SOI MuGFETs

2014 ◽  
Vol 9 (2) ◽  
pp. 97-102
Author(s):  
Fernando F. Teixeira ◽  
Caio C. M. Bordallo ◽  
Marcilei A. Guazzelli ◽  
Paula Ghedini Der Agopian ◽  
João Antonio Martino ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Gate Voltage ◽  
Drain Current ◽  
X Rays ◽  
Back Gate ◽  
X Ray ◽  
Dose Rates ◽  
Buried Oxide ◽  
Opposite Trend

In this work, the X-ray irradiation impact on the back gate conduction and drain current for Triple-Gate SOI FinFETs is investigated for strained and unstrained devices. Both types (P and N) of transistors were analyzed. Since X-rays promote trapped positive charges in the buried oxide, the second interface threshold voltage shifts to lower gate voltage. The performance of n-channel devices presented a strong degradation when submitted to X-rays, while for p-channel devices the opposite trend was observed. Two different dose rates were analyzed.

THE PRODUCTION OF MUTATIONS BY THE IRRADIATION OF MONTCALM BARLEY

1955 ◽  
Vol 33 (6) ◽  
pp. 515-530 ◽  
Author(s):  
Thomas Lawrence
Keyword(s):  
High Dose Rate ◽  
Mutation Induction ◽  
High Dose ◽  
X Rays ◽  
New Approach ◽  
X Ray ◽  
Dose Rates ◽  
Radiation Sources ◽  
Early Maturing ◽  
New Varieties

Five radiation sources were used to induce mutations in barley. All treatments were given at a dosage of 10,000 r. equivalent. The radiation sources with their respective dose-rates in the region of the irradiated seeds were: a betatron (181.8 r./min.), an X-ray machine (201 r./min.), radium-beryllium (5.3 r./min.), and two Co60 sources (4.5 r./min. and 75.75 r./min.). None of the radiation sources used was more effective than the X-ray treatment in producing mutations. The betatron and the high dose-rate treatments from Co60 appear to be somewhat less effective than X-rays. Over 30 different mutant types were produced, including a number of vital mutants, such as stiff-strawed and early-maturing types. These appear promising as new varieties, but require further agronomic evaluation. It is concluded that mutation induction will become a useful new approach for plant breeders.

scholarly journals X-ray Emission Hazards from Ultrashort Pulsed Laser Material Processing in an Industrial Setting

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7163
Author(s):  
Ulf Stolzenberg ◽  
Mayka Schmitt Rahner ◽  
Björn Pullner ◽  
Herbert Legall ◽  
Jörn Bonse ◽  
...  
Keyword(s):  
Material Processing ◽  
High Dose ◽  
Reference Scenario ◽  
X Rays ◽  
Laser Material Processing ◽  
Laser Material ◽  
X Ray ◽  
Dose Rates ◽  
Industrial Setting ◽  
Ambient Dose

Interactions between ultrashort laser pulses with intensities larger than 1013 W/cm2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 1015 W/cm2 at pulse durations of ~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified.

scholarly journals Hard X-Ray Focusing with Curved Reflective Multilayers

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Christian Morawe ◽  
Markus Osterhoff
Keyword(s):  
Experimental Data ◽  
Essential Role ◽  
Multilayer Coating ◽  
Multilayer Coatings ◽  
X Rays ◽  
Optical Performance ◽  
Comprehensive Overview ◽  
X Ray ◽  
Numerical Approaches

This paper provides a comprehensive overview on the utilization of curved graded multilayer coatings as focusing elements for hard X-rays. It concentrates on the Kirkpatrick-Baez (KB) focusing setup that has been developed at 3rd generation synchrotron sources worldwide. The optical performance of these devices is evaluated applying analytical and numerical approaches. The essential role of the multilayer coating and its meridional d-spacing gradient are discussed as well as important technological issues. Experimental data and examples of operational KB focusing devices and applications complement the work.

Radiation Doses to Patients Undergoing Osteosynthesis Procedures

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Staniszewska MA ◽  
◽  
Owsiak E ◽  
Keyword(s):  
Image Intensifier ◽  
X Rays ◽  
Femoral Bone ◽  
Related Factors ◽  
Anatomic Structure ◽  
Factors Affecting ◽  
X Ray ◽  
Dose Rates ◽  
Number Of Factors ◽  
Beam Incident

Fractures of limbs are most frequent causes of orthopaedic interventions. Especially the older people are exposed to these because of motion disorders and osteoporosis. Most of orthopaedic surgery interventions are performed under X-rays control to achieve an optimal settings the anatomical details and also some artificial implants, if such are necessary. Because if that, X-ray units are common equipment in operational theatre where orthopaedic procedures are performed. As a rule they are mobile C-arm units, which are easy available in any time when are necessary. A consequence of every usage of X-rays an exposure to patient but also to operational medical team [1-3]. They are a number of factors affecting both the patient and staff irradiation. There are three categories: patient dependent, equipment dependent and procedure dependent factors. Patient dependent factors include: body thickness in the beam, complexity of the anatomic structure. Equipment dependent factors include: setting of dose rates in pulsed fluoro- and continuous fluoro mode, last image hold, acquisition, and virtual collimation. The main procedure related factors are: number of radiographic frames per run, collimation, fluoroscopic and radiographic acquisition modes, fluoroscopy time, wedge filter, magnification, distance of patient to image receptor (image intensifier or flat panel detector), distance between X-ray tube and patient, and tube angulations. Very important is also the experience of the operator. In case of patient, this is especially important for the procedures when the primary beam can cover the part of the trunk. Such situation has place in the procedure of osteosynthesis the femoral bone, reconstruction of head of femur and also osteosynthesis the humeral bone. Despite a relatively short time of real exposures, doses to patients undergoing these procedures can achieve quite high values: the entrance skin air kerma (here named the “dose”) over 80 mGy was also recorded. Additionally, in practice the primary X-ray beam incident on the same area patient’ body making a higher risk of radiation detriments. The paper presents collection of doses recorded for patients undergoing the procedures of osteosynthesis the femoral bone and the humeral bone during last moths in the big university clinic.

Sign in / Sign up

Export Citation Format

Share Document