Operational properties of fine powder aerosol as radiation detection medium in gaseous proportional counters

Author(s):  
N.F.V. Duarte ◽  
C.M.B. Monteiro ◽  
C.D.R. Azevedo ◽  
A. Antognini ◽  
F.D. Amaro
2017 ◽  
Vol 7 (1) ◽  
Author(s):  
F. D. Amaro ◽  
C. M. B. Monteiro ◽  
J. M. F. dos Santos ◽  
A. Antognini

Abstract The high neutron detection efficiency, good gamma-ray discrimination and non-toxicity of 3He made of proportional counters filled with this gas the obvious choice for neutron detection, particularly in radiation portal monitors (RPM), used to control the illicit transport of nuclear material, of which neutron detectors are key components. 3He is very rare and during the last decade this gas has become increasingly difficult to acquire. With the exception of BF3, which is toxic, no other gas can be used for neutron detection in proportional counters. We present an alternative where the 3He atoms are replaced by nanoparticles made of another neutron sensitive material, 10B. The particles are dispersed in a gaseous volume, forming an aerosol with neutron sensitive properties. A proportional counter filled with such aerosol was exposed to a thermal neutron beam and the recorded response indicates that the neutrons have interacted with the particles in the aerosol. This original technique, which transforms a standard proportional gas mixture into a neutron sensitive aerosol, is a breakthrough in the field of radiation detection and has the potential to become an alternative to the use of 3He in proportional counters.


2020 ◽  
Vol 4 (4) ◽  
pp. 281-290
Author(s):  
S.B. Dabylova ◽  
Yu.N. Kopach ◽  
S.K. Sakhiyev ◽  
D.N. Grozdanov ◽  
N.A. Fedorov

The work is devoted to determining the response function of the detector NaI(Tl) for g -quanta with energy of 4.43 MeV, formed during inelastic scattering of neutrons with energy of 14.1 MeV on the nuclei 12C. In gamma spectrometry, output pulses are recorded, the amplitudes of which are proportional to the energy lost in the detection medium by incident photons. One of the main tasks of radiation detection is to restore radiation characteristics from signals measured at the outputs of detectors. For this, it is necessary to know, first of all, the general characteristics of detectors as converters of radiation into signals. The main characteristic of the detector is its response function, which can be defined as the probability that a particle with given properties generates a certain signal in the detector that will be registered by the device. The article presents the results of modeling the response function of a scintillation detector based on a NaI(Tl) crystal for gamma radiation from inelastic fast neutron scattering in order to study the mechanism of its formation.


Author(s):  
Yimei Zhu ◽  
Masaki Suenaga ◽  
R. L. Sabatini ◽  
Youwen Xu

The (110) twin structure of YBa2Cu3O7 superconductor oxide, which is formed to reduce the strain energy of the tetragonal to orthorhombic phase transformation by alternating the a-b crystallographic axis across the boundary, was extensively investigated. Up to now the structure of the twin boundary still remained unclear. In order to gain insight into the nature of the twin boundary in Y-Ba-Cu-O system, a study using electron diffraction techniques including optical and computed diffractograms, as well as high resolution structure imaging techniques with corresponding computer simulation and processing was initiated.Bulk samples of Y-Ba-Cu-O oxide were prepared as described elsewhere. TEM specimens were produced by crushing bulk samples into a fine powder, dispersing the powder in acetone, and suspending the fine particles on a holey carbon grid. The electron microscopy during this study was performed on both a JEOL 2000EX and 2000FX electron microscopes operated at 200 kV.


Author(s):  
G.D. Danilatos

The environmental scanning electron microscope (ESEM) has evolved as the natural extension of the scanning electron microscope (SEM), both historically and technologically. ESEM allows the introduction of a gaseous environment in the specimen chamber, whereas SEM operates in vacuum. One of the detection systems in ESEM, namely, the gaseous detection device (GDD) is based on the presence of gas as a detection medium. This might be interpreted as a necessary condition for the ESEM to remain operational and, hence, one might have to change instruments for operation at low or high vacuum. Initially, we may maintain the presence of a conventional secondary electron (E-T) detector in a "stand-by" position to switch on when the vacuum becomes satisfactory for its operation. However, the "rough" or "low vacuum" range of pressure may still be considered as inaccessible by both the GDD and the E-T detector, because the former has presumably very small gain and the latter still breaks down.


Author(s):  
J.P.S. Hanjra

Tin mono selenide (SnSe) with an energy gap of about 1 eV is a potential material for photovoltaic applications. Various authors have studied the structure, electronic and photoelectronic properties of thin films of SnSe grown by various deposition techniques. However, for practical photovoltaic junctions the electrical properties of SnSe films need improvement. We have carried out investigations into the properties of flash evaporated SnSe films. In this paper we report our results on the structure, which plays a dominant role on the electrical properties of thin films by TEM, SEM, and electron diffraction (ED).Thin films of SnSe were deposited by flash evaporation of SnSe fine powder prepared from high purity Sn and Se, onto glass, mica and KCl substrates in a vacuum of 2Ø micro Torr. A 15% HF + 2Ø% HNO3 solution was used to detach SnSe film from the glass and mica substrates whereas the film deposited on KCl substrate was floated over an ethanol water mixture by dissolution of KCl. The floating films were picked up on the grids for their EM analysis.


Author(s):  
Shoichiro Fukusako ◽  
Masahiko Yamada ◽  
Akihiko Horibe ◽  
T. Ohmichi

2006 ◽  
Vol 40 (93) ◽  
pp. 21-28
Author(s):  
Yasuhiro OKAMOTO ◽  
Norio KATAOKA ◽  
Yoshiyuki UNO ◽  
Eiji YUASA ◽  
Shin-ichiro KUBOTA

Author(s):  
Muhammad Irfan ◽  
Safdar Abbas ◽  
Beenish Jehan Azhar ◽  
Shakeel Ahmad ◽  
Hafsa Muhammad ◽  
...  

Background: Phytonutrients in peach fruits have health promoting antioxidants against various chronic diseases. However, there is no extensive data to show the nutritional values of Local peach cultivars after post-harvest treatments. Objective: Mainly this study was objective to determine the effect of calcium carbide on nutritional value and quality of fruits of Pakistani peach cultivars. Methods: The peach fruits were collected from three different peach orchids of KPK and the fruits were divided into 4 groups while 5th group was collected from local fruit shop. Each experimental group was treated with different concentration of calcium carbide whereas control group was not treated. The peel and pulp samples were oven dried and ground to fine powder separately. The elemental compositions were determined using Particle Induced X-ray emission and Pelletron Tandem Accelerator. Result: Sixteen elements were identified in peach fruits and the elements were Al, P, S, Cl, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, and Se. In peel, concentration of some elements increased or decreased after treatment with CaC2 while in pulp the conc. of nearly all detected elements was increased in treated samples. We found significantly high amount of heavy metals traces including As, Se, Co, Si, and P in peach fruits treated with CaC2. Interestingly, the presence of trichomes in peach skin prevents the transfer of these heavy metals deep into the pulp which was also verified by the elemental profiling of nectarines. Conclusion: Conclusively, the artificial ripening with CaC2 changed the nutritional value of peach fruits that has higher health risks if consume with the peel. According to our best knowledge, this is the first report that highlights the effects of CaC2 which deteriorate the nutritional value of peach fruits in Pakistan.


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