Papers by M. Lamehi-rachti
Acta Physica Polonica B, 2017
In this research work, thick target yields for gamma-ray emission from the S(d, pγ1)S (Eγ = 841 k... more In this research work, thick target yields for gamma-ray emission from the S(d, pγ1)S (Eγ = 841 keV) nuclear reaction were measured by bombarding pure-element sulfur target with deuterons in the energy range of 1300–2000 keV. Gamma rays were detected with a high purity germanium detector (HPGe) placed at an angle of 90◦ with respect to the beam direction. The obtained thick target gamma-ray yields were compared with the previously published data. The overall systematic uncertainty of the thick target yield values was estimated to be better than ±9%. The measurements were conducted in a reaction chamber optimized for Particle Induced Gamma-ray Emission (PIGE) spectrometry. The main advantage of this reaction chamber is that the employed charged particle detector can be readily approached to or retracted from the target — along the preferred direction of RBS measurement — during the experiments to perform PIGE measurements with the least possible uncertainty in beam charge collection ...
The effect of surface roughness on the secondary electron emission from a sandblasted surface is ... more The effect of surface roughness on the secondary electron emission from a sandblasted surface is investigated using a Monte-Carlo method. Sandblasted surfaces can significantly reduce the secondary emission yield and have a large sensitivity to the percentage of surface roughness.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2017
The unique ionization pattern of MeV-energy ion beam is applied for efficient luminescence analys... more The unique ionization pattern of MeV-energy ion beam is applied for efficient luminescence analysis of a collection of natural turquoise samples. The considerable penetration depth of tens of micrometer and enhancement of energy deposition with depth, suggests ionoluminescence as an appropriate technique for studying weakly luminescent minerals. Herein, the luminescence induced in deeper parts of turquoise samples is extracted through their relatively transparent adjacent host stones. The resulting intense spectra reveal the vibrational structure of the broad green luminescence band of turquoise which probably originates from O 2 centers. Moreover, owing to the applied ionoluminescence approach, red and blue luminescence bands of turquoise were observed which can be ascribed to Fe 3+ ions and UO 2 2+ centers respectively. The elemental information of the samples is provided using micro-PIXE analysis technique.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017
Thick target excitation yield curves of gamma-rays from the reactions 27 Al(p,p 0 c) 27 Al (E c =... more Thick target excitation yield curves of gamma-rays from the reactions 27 Al(p,p 0 c) 27 Al (E c = 844 and 1014 keV), 27 Al(p,ac) 27 Al (E c = 1369 keV), 28 Si(p,p 0 c) 28 Si (E c = 1779 keV), 29 Si(p,p 0 c) 29 Si (E c = 1273 keV) and 31 P(p,p 0 c) 31 P (E c = 1266 keV) were measured by bombarding pure-element targets with protons at energies below 3 MeV. Gamma-rays were detected with a High Purity Ge detector placed at an angle of 90°with respect to the beam direction. The obtained thick target gamma-ray yields were compared with the previously published data. The overall systematic uncertainty of the thick target yield values was estimated to be better than ±9%.
Journal of Luminescence, 2017
Natural heterogeneous lapis lazuli has been investigated using the complementary techniques of io... more Natural heterogeneous lapis lazuli has been investigated using the complementary techniques of ionoluminescence spectroscopy, ionoluminescence microscopy and micro-PIXE. The equivalent probed depths, the possibility of simultaneous use and the capability of non-destructive in-air application suggest the combined use of ionoluminescence and micro-PIXE techniques as an appropriate approach in mineral analysis to reveal the texture, chemical composition, and elemental distribution of the samples. In this research work, the various mineral phases of a lapis lazuli sample were detected and analyzed. It was possible to identify most of the minerals in the analyzed area, including apatite, a mineral phase uncommon in lapis lazuli, and point out different luminescence features of crystals of the same mineral, diopside, found in different parts of the same lapis lazuli sample.
Radiation Physics and Chemistry, 2017
Abstract A new version of the Iranian Noble Gas Analyzing System (INGAS) has been improved to fac... more Abstract A new version of the Iranian Noble Gas Analyzing System (INGAS) has been improved to facilitate measurement of beta-gamma coincidence events. It employs a new prototype list-mode multi-parameter data analyzer system, MPA4300. In order to test the new version performance, it has used to obtain energy spectra from radioxenon isotopes using the detector assembly of the Iranian Noble Gas Analyzing System. The MPA4300 is able to set the coinciding parameters, extract the corresponding spectrum, and through the use of event by event list file, can replay the measurement in offline mode. A great novelty of this work is the use of internal timing circuit in MPA4300 instead of using standard pick up time modules to identify coincidence events of detectors. A detailed description of the measuring 222Rn and 131mXe is presented.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2016
Differential cross sections of the 24 Mg(d,p 0,1,2,3,4) reactions were obtained in the range E d,... more Differential cross sections of the 24 Mg(d,p 0,1,2,3,4) reactions were obtained in the range E d,lab = 1.2-2 MeV and at the scattering angles of 90°, 135°, 150°and 165°using a thin Mg target having thickness of 76.7 ± 3.1 lg/cm 2. The cross section values were determined with an average energy step of $25 keV while the detailed measurements were carried out with an energy step of $5 keV around the resonance peaks. Elastic scattering data for three steep backward angles (135°, 150°and 165°) were also studied for the same incident deuteron energy range and steps. The results were compared with those of the previous studies. Moreover, the validity of the measured data has been benchmarked using a thick Mg target at two deuteron beam energies of 1.7 and 2 MeV.
Radiation Measurements, 2015
Physics Procedia, 2015
Abstract In this work, an optimized computer controlled electrochemical cell were designed and co... more Abstract In this work, an optimized computer controlled electrochemical cell were designed and constructed. This Electrolytic cell was used for etching latent ion tracks and electrochemical deposition of wires in pores of etched-ion tracks foils. The applied voltage and current through the electrochemical cell during the etching and electrodeposition were measured and monitored in real time by a Data Analysis system. Monitoring the current time curve during the filling of pores and growth of micro and nano wires allows one to stop the deposition process after a given time to obtain nano- and micro wire of a predefined length. In this work, Design and manufacture of a sealed electrochemical cell was done in a manner that one can change distance between electrodes and geometry of cathodes. Data analysis system was used to measuring and monitoring of applied voltage and current through the cell consists of three parts: Amplifier, Data acquisition (DAQ) system and Software. A current amplifier that used in data analysis system is a log ratio amplifier. A log ratio amplifier provides an output voltage proportional to the log base 10 of the ratio input current I 1 (current during the electrodeposition of wire in cell) and Input current I 2 (flexible current of precision current source). A DAQ reading output voltage of amplifier and send to Computer. With lab view software analyzed the voltage and converted to the current corresponding to the electrodeposition of wires. Current amplifier designed and built in this work is a noise suppression that can measure small current through the cell with high accuracy. Advantage of proposed log ratio amplifier is one can used this amplifier for measuring and monitoring of current during the filling of pores and growth of wires in the etched ion track foils with various track density.
2010 18th Iranian Conference on Electrical Engineering, 2010
There are many methods for fabricat ing electron linear accelerator cav ities. In the present res... more There are many methods for fabricat ing electron linear accelerator cav ities. In the present research two methods were chosen: first, separable parts (separate ring and disks) and second, parallel d isks and cylinder (integrated). The resonance frequencies of cavities and the quality factor of each frequency are two important parameters in their performance. The co mparison of measured parameters of the cavit ies made with two methods, firstly by the network analyzer mach ine and secondly using the HFSS simu lator. The results of both the practical measurements and the simu lation of the two structures indicated that the integrated method is better for imp le menting cavities.
pp 323 of Contributions to the International Conference on Properties of Nuclear States, Montreal, Canada, August 25--30, 1969. Montreal Les Presses de l'Universite de Montreal (1969)., 1969
Quasi-elastic scattering of 6He at E_lab=27 MeV from 197Au has been measured in the angular range... more Quasi-elastic scattering of 6He at E_lab=27 MeV from 197Au has been measured in the angular range of 6-72 degrees in the laboratory system employing LEDA and LAMP detection systems. These data, along with previously analysed data of 6He + 208Pb at the same energy, are analyzed using Optical Model calculations. The role of Coulomb dipole polarizability has been investigated. Large imaginary diffuseness parameters are required to fit the data. This result is an evidence for long range absorption mechanisms in 6He induced reactions. Comment: 10 pages, 10 figures, minor corrections. To appear in Nucl. Phys.
Radiation Measurements, 2015
h i g h l i g h t s The RBS/C spectrum of 1400 keV deuterons along the Si <100> was taken and ana... more h i g h l i g h t s The RBS/C spectrum of 1400 keV deuterons along the Si <100> was taken and analyzed. A simulation method was proposed to determine characteristic channeling parameters. The simulation was done based on the basic concept of the channeling phenomena. The dechanneling process was clearly explained by the Gompertz sigmoidal function. The energy loss ratio and its dependence on the energy of 1e2 MeV were studied.
Journal of Archaeological Science: Reports, 2020
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Papers by M. Lamehi-rachti