scholarly journals Особенности фотолюминесценции в кристаллах ниобата лития, легированных цинком в широком диапазоне концентраций

2021 ◽  
Vol 129 (5) ◽  
pp. 634
Author(s):  
Н.В. Сидоров ◽  
М.В. Смирнов ◽  
М.Н. Палатников ◽  
В.Б. Пикулев
Keyword(s):  
Zinc Concentration ◽  
High Energy ◽  
Photoluminescence Spectra ◽  
High Energy Region ◽  
Luminescence Centers ◽  
Nonradiative Transitions ◽  
Concentration Changes ◽  
Zno Crystal ◽  
Concentration Threshold ◽  
Different Origin

The concentration changes in the photoluminescence spectra of LiNbO3 : Zn crystals (0.004 ÷ 6.5 mol.% ZnO) were studied. It was found that with the increase of zinc concentration from 0.004 to 1.42 mol.% ZnO, the intensity decrease of luminescence bands caused by VLI, NbNb, and NbNb−NbLi defects was observed. As the crystal composition approached the second concentration threshold (≈ 7.0 mol.% ZnO), the luminescent halo shifted by ≈ 0.41 eV to the high-energy region of the spectrum and the intensity of the luminescence centers increased at 2.66 and 2.26 eV. It was caused by the appearance of ZnLi point defects. It was shown that in the LiNbO3 : Zn(4.69 mol.% ZnO) crystal obtained by homogeneous doping technology, there is a greater number of luminescence centers of different origin than in congruent and zinc-doped crystals obtained by direct melt doping technology. In the LiNbO3 : Zn crystal (4.52 mol.% ZnO), the luminescence of the main defects (VLi, NbNb, ZnLi) was quenched by increasing the fraction of nonradiative transitions relative to other LiNbO3 : Zn crystals in the concentration range [ZnO] = 4.46 ÷ 6.50 mol.%.

scholarly journals Analysis of Shielding Performance of Radiation-Shielding Materials According to Particle Size and Clustering Effects

2021 ◽  
Vol 11 (9) ◽  
pp. 4010
Author(s):  
Seon-Chil Kim
Keyword(s):  
Particle Size ◽  
Polymer Material ◽  
Energy Region ◽  
High Energy ◽  
Radiation Shielding ◽  
High Energy Region ◽  
Particle Structure ◽  
Effect Of Particle Size ◽  
Extensive Body ◽  
Shielding Material

In the field of medical radiation shielding, there is an extensive body of research on process technologies for ecofriendly shielding materials that could replace lead. In particular, the particle size and arrangement of the shielding material when blended with a polymer material affect shielding performance. In this study, we observed how the particle size of the shielding material affects shielding performance. Performance and particle structure were observed for every shielding sheet, which were fabricated by mixing microparticles and nanoparticles with a polymer material using the same process. We observed that the smaller the particle size was, the higher both the clustering and shielding effects in the high-energy region. Thus, shielding performance can be improved. In the low-dose region, the effect of particle size on shielding performance was insignificant. Moreover, the shielding sheet in which nanoparticles and microsized particles were mixed showed similar performance to that of the shielding sheet containing only microsized particles. Findings indicate that, when fabricating a shielding sheet using a polymer material, the smaller the particles in the high-energy region are, the better the shielding performance is. However, in the low-energy region, the effect of the particles is insignificant.

Luminescence Centers in High-Energy Ion-Implanted Silicon

1997 ◽  
Vol 258-263 ◽  
pp. 587-592 ◽  
Author(s):  
Koichi Terashima ◽  
Taeko Ikarashi ◽  
Masahito Watanabe ◽  
Tomohisa Kitano
Keyword(s):  
High Energy ◽  
Luminescence Centers ◽  
Ion Implanted

scholarly journals π--PInteraction in High Energy Region

1957 ◽  
Vol 18 (3) ◽  
pp. 264-268 ◽  
Author(s):  
Daisuke Ito ◽  
Tetsuro Kobayashi ◽  
Miwae Yamazaki ◽  
Shigeo Minami
Keyword(s):  
Energy Region ◽  
High Energy ◽  
High Energy Region

3.3.6.4 The high-energy region

2005 ◽  
pp. 306-309
Author(s):  
A. Fasso ◽  
K. Göbel ◽  
M. Höfert ◽  
J. Ranft ◽  
G. Stevenson
Keyword(s):  
Energy Region ◽  
High Energy ◽  
High Energy Region

Charge transfer in collisions of atomic hydrogen withN7+ions in the high-energy region

1987 ◽  
Vol 36 (4) ◽  
pp. 1656-1662 ◽  
Author(s):  
G. C. Saha ◽  
Shyamal Datta ◽  
S. C. Mukherjee
Keyword(s):  
Charge Transfer ◽  
Atomic Hydrogen ◽  
Energy Region ◽  
High Energy ◽  
High Energy Region

Formation of antihydrogen in the ground state

2007 ◽  
Vol 85 (4) ◽  
pp. 393-399
Author(s):  
V S Kulhar
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Time Reversal ◽  
Exchange Process ◽  
Hydrogen Charge ◽  
High Energy ◽  
High Energy Region ◽  
Charge Exchange Process ◽  
State Approximation ◽  
Reversal Invariance

Cross sections for antihydrogen formation in the ground state for the process [Formula: see text] + Ps(nlm) → [Formula: see text](1s) + e– have been calculated using charge conjugation and time reversal invariance. Calculations are based on a two-state approximation method, used by the author earlier for positron–hydrogen charge -exchange process (e+ – H → Ps(nlm) + p). Cross-section results are reported in the intermediate- and high-energy region (20 keV – 500 keV). PACS No.: 36.10.Dr

An empirical derivation of the X-ray optic transmission profile used in calibrating the Planetary Instrument for X-ray Lithochemistry (PIXL) for Mars 2020

2018 ◽  
Vol 33 (2) ◽  
pp. 162-165 ◽  
Author(s):  
C. M. Heirwegh ◽  
W. T. Elam ◽  
D. T. Flannery ◽  
A. C. Allwood
Keyword(s):  
Energy Region ◽  
High Energy ◽  
Conventional Approach ◽  
Smoothing Algorithm ◽  
Correction Factors ◽  
High Energy Region ◽  
X Ray ◽  
Straightforward Method ◽  
Specific Correction ◽  
Energy Portion

Calibration of the prototype Planetary Instrument for X-ray Lithochemistry (PIXL) selected for Mars 2020 has commenced with an empirical derivation of the X-ray optic transmission profile. Through a straightforward method of dividing a measured “blank” spectrum over one calculated assuming no optic influence, a rudimentary profile was formed. A simple boxcar-smoothing algorithm was implemented to approximate the complete profile that was incorporated into PIQUANT. Use of this form of smoothing differs from the more conventional approach of using a parameter-based function to complete the profile. Comparison of element-specific correction factors, taken from a measurement of NIST SRM 610, was used to assess the accuracy of the new profile. Improvement in the low- to mid-energy portion of the data was apparent though the high-energy region diverged from unity, and thus, requires further refinement.

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