scholarly journals Photon spectra from quark generation by WIMPs

2011 ◽  
Author(s):  
J. A. R. Cembranos ◽  
A. Cruz-Dombriz ◽  
A. Dobado ◽  
R. Lineros ◽  
A. L. Maroto
Keyword(s):  
Photon Spectra ◽  
Quark Generation

scholarly journals Impact of secondary particles on microdistribution of deposited dose in biological tissue in the presence of gold and gadolinium nanoparticles under photon beam irradiation

2019 ◽  
Vol 5 (2) ◽  
pp. 109-116
Author(s):  
Ivan A. Konobeev ◽  
Yurij A. Kurachenko ◽  
Igor’ N. Sheino
Keyword(s):  
Biological Tissue ◽  
Biological Tissues ◽  
Photon Beam ◽  
Additional Dose ◽  
Tissue Water ◽  
Secondary Particles ◽  
Photon Sources ◽  
Initial Spectrum ◽  
Photon Spectra ◽  
The Impact

It is experimentally proven that nanoparticles of high-Z materials can be used as radiosensitizers for photon beam therapy. In the authors’ opinion, data available as of today on the impact of secondary particles (electrons, photons and positrons generated in biological tissue by penetrating beam of primary photons) on the distribution of deposited dose during photon beam therapy in the presence of nanoparticles, are insufficient. Investigation of this impact constituted the main goal of this work. Two-stage simulation was performed using Geant4 platform. During the first stage a layer of biological tissue (water) was irradiated by monoenergetic photon sources with energies ranging from 10 keV to 6 MeV. As the result of this modeling spectra of electrons, photons and positrons were obtained at the depth of 5 cm. During the second stage the obtained photon spectra were used to irradiate gold, gadolinium and water nanoparticles. Radial distributions of energy deposited around nanoparticles were obtained as the result of this modeling. Radial DEF (Dose Enhancement Factor) values around nanoparticles of gold and gadolinium positioned in water at the depth of 5 cm were obtained after processing the collected data. Contributions from primary photons and secondary particles (electrons, photons and positrons generated in the layer of water with 5-cm thickness by the penetrating beam of primary photons) in the additional dose deposited around the nanoparticles were calculated as well. It was demonstrated that layer of biological tissue placed between the source of photons and nanoparticles considerably changes the initial spectrum of photons and this change is significant in the analysis of mechanism of radiosensitization of biological tissues by nanoparticles for all energies of photon sources (up to 6 MeV). It was established that interaction of electrons and positrons with nanoparticles does not lead to significant increase of additional dose in the vicinity of their surfaces and can be most likely excluded from consideration in the analysis of radiosensitization mechanism of nanoparticles.

Erratum: Two-photon spectra of single-crystal gadolinium diglycolate

1991 ◽  
Vol 44 (14) ◽  
pp. 7769-7769
Author(s):  
Tapanendu Kundu ◽  
Asok K. Banerjee ◽  
Mihir Chowdhury
Keyword(s):  
Single Crystal ◽  
Two Photon ◽  
Photon Spectra

Two-photon spectra of C 60 and C 70 films between 0.74 and 1.7 μm

1997 ◽  
Author(s):  
Friedrich P. Strohkendl ◽  
Theresa J. Axenson ◽  
R. J. Larsen ◽  
Larry R. Dalton ◽  
Robert W. Hellwarth ◽  
...  
Keyword(s):  
Two Photon ◽  
Photon Spectra

PHOTON SPECTRA FROM PION ABSORPTION ON 3He AND 6Li

1972 ◽  
pp. 877-881
Author(s):  
Helmut W. Baer ◽  
James A. Bistirlich ◽  
Kenneth M. Crowe ◽  
Jerome A. Helland ◽  
Peter Truöl
Keyword(s):  
Pion Absorption ◽  
Photon Spectra

scholarly journals Scaling properties of direct photon yields in heavy ion collisions

2020 ◽  
Vol 80 (7) ◽  
Author(s):  
Vladimir Khachatryan ◽  
Michał Praszałowicz
Keyword(s):  
Scaling Laws ◽  
Heavy Ion ◽  
Charged Hadron ◽  
Direct Photon ◽  
Recent Analysis ◽  
Scaling Properties ◽  
Ion Collisions ◽  
Phenix Collaboration ◽  
Measurement Results ◽  
Photon Spectra

Abstract A recent analysis from the PHENIX collaboration of available direct photon measurement results in collisions of various systems such as Au+Au, Cu+Cu, and Pb+Pb, at different beam energies ranging from 39 to 2760 GeV, has shown a universal, within experimental uncertainties, multiplicity scaling, in which direct photon $$p_{T}$$pT-spectra for transverse momenta up to 2 GeV/c are scaled with charged hadron pseudorapidity density at midrapidity raised to power $$\alpha =1.25$$α=1.25. On the other hand, those direct photon $$p_{T}$$pT-spectra also exhibit geometrical scaling in the similar $$p_{T}$$pT range. Assuming power-law dependence of the scaled photon spectra for both scaling laws, we formulate two independent conditions for the power $$\alpha $$α, which overshoot experimental data by $$\sim 10\%$$∼10% on average. We discuss possible sources that might improve this estimate.

Coulomb correlations and two-photon spectra of conjugated polymers

1990 ◽  
Vol 171 (1-2) ◽  
pp. 14-18 ◽  
Author(s):  
Z.G. Soos ◽  
P.C.M. McWilliams ◽  
G.W. Hayden
Keyword(s):  
Conjugated Polymers ◽  
Two Photon ◽  
Photon Spectra ◽  
Coulomb Correlations
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