Dimensionally reduced heavy atom semiconductors as candidate materials for γ-ray detection: the case of Cs2Hg6S7

2011 ◽  
Vol 1341 ◽  
Author(s):  
Ioannis Androulakis ◽  
Hao Li ◽  
Christos Malliakas ◽  
John A. Peters ◽  
Zhifu Liu ◽  
...  
Keyword(s):  
Band Gap ◽  
Atomic Number ◽  
Dimensional Reduction ◽  
Mass Density ◽  
Heavy Atom ◽  
High Mass ◽  
Semiconducting Materials ◽  
High Atomic Number ◽  
Semiconductor Compounds ◽  
Γ Ray

ABSTRACTWe address the issue of decreasing band-gap with increasing atomic number, inherent in semiconducting materials, by introducing a concept we call dimensional reduction. The concept leads to semiconductor compounds containing high atomic number elements and simultaneously exhibiting a large band gap and high mass density suggesting that dimensional reduction can be successfully employed in developing new γ-ray detecting materials. As an example we discuss the compound Cs2Hg6S7 that exhibits a band-gap of 1.65eV and mobility-lifetime products comparable to those of optimized Cd0.9Zn0.1Te.

Low-momentum-transfer incoherent γ-ray scattering by moderate- to high-atomic-number elements

1992 ◽  
Vol 45 (3) ◽  
pp. 2097-2100 ◽  
Author(s):  
D. A. Bradley ◽  
C. S. Chong ◽  
A. A. Tajuddin ◽  
A. Shukri ◽  
A. M. Ghose
Keyword(s):  
Momentum Transfer ◽  
Atomic Number ◽  
High Atomic Number ◽  
Γ Ray ◽  
Ray Scattering

scholarly journals THE EFFICIENCY OF RADIATION SHIELDING MADE FROM MATERIALS WITH HIGH ATOMIC NUMBER AND LOW MASS DENSITY

2021 ◽  
pp. 74-79
Author(s):  
V.G. Rudychev ◽  
M.O. Azarenkov ◽  
I.O. Girka ◽  
Y.V. Rudychev
Keyword(s):  
Monte Carlo ◽  
Atomic Number ◽  
Spent Nuclear Fuel ◽  
Mass Density ◽  
Radiation Shielding ◽  
High Atomic Number ◽  
The Monte Carlo Method ◽  
Low Mass ◽  
High Burnup ◽  
Method Show

The radiation shielding from γ-quanta of the existing transport containers (TC) for transportation of spent nuclear fuel (SNF) is made of steel or steel plus Pb 25…30 cm thick and weighting ~ 60…80 t. The application of materials with high atomic number, dispersed (solids grinded to a powdery state) to the densities in the range 4 < ρ < 8 g/cm3, is investigated. Simulations based on the Monte Carlo method show that at the densities of dispersed depleted U larger than 5 g/cm3 and shielding thicknesses of more than 30 cm, the absorption of γ-quanta of SNF is greater than that of the shielding made of steel of the same thickness. The application of such materials, while the weight characteristics of the shields are not exceeded, provides radiation shielding for SNF with the high burnup rate and the smaller cooling time or larger amount of the transported SNF.

Small-angle coherent γ-ray scattering for moderate- to high-atomic-number elements

1990 ◽  
Vol 41 (11) ◽  
pp. 5974-5979 ◽  
Author(s):  
D. A. Bradley ◽  
C. S. Chong ◽  
A. A. Tajuddin ◽  
A. Shukri ◽  
A. M. Ghose
Keyword(s):  
Atomic Number ◽  
Small Angle ◽  
High Atomic Number ◽  
Γ Ray ◽  
Ray Scattering

scholarly journals Strong Lensing Mass Reconstruction: from Frontier Fields to the Typical Lensing Clusters of Future Surveys

2015 ◽  
Vol 11 (A29B) ◽  
pp. 793-794
Author(s):  
Keren Sharon ◽  
Michael D. Gladders ◽  
Jane R. Rigby ◽  
Matthew B. Bayliss ◽  
Eva Wuyts ◽  
...  
Keyword(s):  
Mass Density ◽  
High Redshift ◽  
High Mass ◽  
Quality Data ◽  
High Quality Data ◽  
Strong Lensing ◽  
Modeling Techniques ◽  
Lens Modeling ◽  
High Redshift Universe ◽  
Mass Reconstruction

AbstractDriven by the unprecedented wealth of high quality data that is accumulating for the Frontier Fields, they are becoming some of the best-studied strong lensing clusters to date, and probably the next few years. As will be discussed intensively in this focus meeting, the FF prove transformative for many fields: from studies of the high redshift Universe, to the assembly and structure of the clusters themselves. The FF data and the extensive collaborative effort around this program will also allow us to examine and improve upon current lens modeling techniques. Strong lensing is a powerful tool for mass reconstruction of the cores of galaxy clusters of all scales, providing an estimate of the total (dark and seen) projected mass density distribution out to 0.5 Mpc. Though SL mass may be biased by contribution from structures along the line of sight, its strength is that it is relatively insensitive to assumptions on cluster baryon astrophysics and dynamical state. Like the Frontier Fields clusters, the most “famous” strong lensing clusters are at the high mass end; they lens dozens of background sources into multiple images, providing ample lensing constraints. In this talk, I will focus on how we can leverage what we learn from modeling the FF clusters in strong lensing studies of the hundreds of clusters that will be discovered in upcoming surveys. In typical clusters, unlike the Frontier Fields, the Bullet Cluster and A1689, we observe only one to a handful of background sources, and have limited lensing constraints. I will describe the limitations that such a configuration imposes on strong lens modeling, highlight measurements that are robust to the richness of lensing evidence, and address the sources of uncertainty and what sort of information can help reduce those uncertainties. This category of lensing clusters is most relevant to the wide cluster surveys of the future.

scholarly journals Theoretical considerations for star formation at low and high redshift

2015 ◽  
Vol 11 (S315) ◽  
pp. 247-253
Author(s):  
Bruce G. Elmegreen
Keyword(s):  
Star Formation ◽  
Mass Density ◽  
High Redshift ◽  
Distribution Functions ◽  
High Mass ◽  
Formation Processes ◽  
Accretion Rates ◽  
Major Merger ◽  
Cloud Cores ◽  
Self Gravity

AbstractStar formation processes in strongly self-gravitating cloud cores should be similar at all redshifts, forming single or multiple stars with a range of masses determined by local magneto-hydrodynamics and gravity. The formation processes for these cores, however, as well as their structures, temperatures, Mach numbers, etc., and the boundedness and mass distribution functions of the resulting stars, should depend on environment, as should the characteristic mass, density, and column density at which cloud self-gravity dominates other forces. Because the environments for high and low redshift star formation differ significantly, we expect the resulting gas to stellar conversion details to differ also. At high redshift, the universe is denser and more gas-rich, so the active parts of galaxies are denser and more gas rich too, leading to slightly shorter gas consumption timescales, higher cloud pressures, and denser, more massive, bound stellar clusters at the high mass end. With shorter consumption times corresponding to higher relative cosmic accretion rates, and with the resulting higher star formation rates and their higher feedback powers, the ISM has greater turbulent speeds relative to the rotation speeds, thicker gas disks, and larger cloud and star complex sizes at the characteristic Jeans length. The result is a more chaotic appearance at high redshift, bridging the morphology gap between today's quiescent spirals and today's major-mergers, with neither spiral nor major-merger processes actually in play at that time. The result is also a thick disk at early times, and after in-plane accretion from relatively large clump torques, a classical bulge. Today's disks are thinner, and torque-driven accretion is slower outside of inner barred regions. This paper reviews the basic processes involved with star formation in order to illustrate its evolution over time and environment.

Backscatter dose effects for high atomic number materials being irradiated in the presence of a magnetic field: A Monte Carlo study for the MRI linac

2016 ◽  
Vol 43 (8Part1) ◽  
pp. 4665-4673 ◽  
Author(s):  
Syed Bilal Ahmad ◽  
Arman Sarfehnia ◽  
Anthony Kim ◽  
Matt Wronski ◽  
Arjun Sahgal ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Atomic Number ◽  
Monte Carlo Study ◽  
High Atomic Number ◽  
Dose Effects
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