نتایج جستجو برای: incident beam 635 mev

تعداد نتایج: 173717  

Journal: :Medical physics 1981
A R Smith W Schimmerling L L Kanstein J G McCaslin R H Thomas

We have identified the sources of neutron production in the beam transport system of the 720-MeV helium beam used for radiation therapy at the 184-in synchrocyclotron of the Lawrence Berkeley Laboratory, and determined their magnitude. Measurements with activation detectors of differing energy response were used to unfold secondary particle spectra at various locations on the patient table. The...

2016
Juergen Meyer Matthew J. Nyflot Wade P. Smith Landon S. Wootton Lori Young Fei Yang Minsun Kim Kristi R. G. Hendrickson Eric Ford Alan M. Kalet Ning Cao Claire Dempsey George A. Sandison

Monthly QA is recommended to verify the constancy of high-energy electron beams generated for clinical use by linear accelerators. The tolerances are defined as 2%/2 mm in beam penetration according to AAPM task group report 142. The practical implementation is typically achieved by measuring the ratio of readings at two different depths, preferably near the depth of maximum dose and at the dep...

Journal: :Physical review letters 2001
M I Santala Z Najmudin E L Clark M Tatarakis K Krushelnick A E Dangor V Malka J Faure R Allott R J Clarke

A highly relativistic electron beam produced by a 50 TW laser-plasma accelerator has been characterized by photonuclear techniques. The beam has large divergence that increases with plasma density. The electron yield also increases with plasma density and reaches up to 4x10(11) electrons ( >10 MeV), with beam current approaching the Alfvén limit. Effective electron temperatures exceeding 8 MeV ...

Journal: :Medical physics 2012
D A Roberts V N Hansen M G Thompson G Poludniowski A Niven J Seco P M Evans

PURPOSE In this paper, the effect on image quality of significantly reducing the primary electron energy of a radiotherapy accelerator is investigated using a novel waveguide test piece. The waveguide contains a novel variable coupling device (rotovane), allowing for a wide continuously variable energy range of between 1.4 and 9 MeV suitable for both imaging and therapy. METHOD Imaging at lin...

2015
Kirk T. McDonald Joseph Henry

in high-energy photon interactions with a nucleus A, as recently suggested in [7] (slide 23). Of course, muon-pair production by this process is suppressed relative to electron-positron pair production by the ratio (me/mμ) 2 ≈ 1/40, 000, so there is an issue of the efficiency of muon production via reaction (1). The Bethe-Heitler process (1) is further suppressed near threshold, so it would be ...

2013
T Gorjiara Z Kuncic J Adamovics C Baldock

PRESAGE is a radiochromic solid dosimeter which shows promising potential for 3D proton beam dosimetry. Since an idea dosimeter should be water-equivalent, total depth dose distributions in two PRESAGE formulations irradiated by a 62 MeV proton beam were compared with that in water using GEANT4 Monte Carlo simulations. The dose delivered by secondary particles was also calculated. Our results s...

2009
M. Lavalle P. G. Fuochi A. Martelli U. Corda A. Kovács K. Mehta F. Kuntz S. Plumeri

An easy-to-use and robust energy monitoring device has been developed for reliable detection of dayto-day small variations in the electron beam energy, a critical parameter for quality control and quality assurance in industrial radiation processing. It has potential for using on-line, thus providing real-time information. Its working principle is based on the measurement of currents, or charge...

Journal: :Physical review letters 2016
D Abbott P Adderley A Adeyemi P Aguilera M Ali H Areti M Baylac J Benesch G Bosson B Cade A Camsonne L S Cardman J Clark P Cole S Covert C Cuevas O Dadoun D Dale H Dong J Dumas E Fanchini T Forest E Forman A Freyberger E Froidefond S Golge J Grames P Guèye J Hansknecht P Harrell J Hoskins C Hyde B Josey R Kazimi Y Kim D Machie K Mahoney R Mammei M Marton J McCarter M McCaughan M McHugh D McNulty K E Mesick T Michaelides R Michaels B Moffit D Moser C Muñoz Camacho J-F Muraz A Opper M Poelker J-S Réal L Richardson S Setiniyaz M Stutzman R Suleiman C Tennant C Tsai D Turner M Ungaro A Variola E Voutier Y Wang Y Zhang

The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an ...

Journal: :Frontiers in Medicine 2021

The pair of copper radionuclides 64 Cu/ 67 Cu (T 1/2 = 12. 7 h/61.8 h) allows, respectively, PET imaging and targeted beta therapy. An analysis the different production routes with charged particles was performed reaction 70 Zn(d,x) route identified as a promising one. It may allow without Cu. cross section has been measured up to 28.7 MeV. Measurements were done using well-known stacked-foils ...

Journal: :Physical Review Letters 2021

We have performed the first direct measurement of Rb83(p,γ) radiative capture reaction cross section in inverse kinematics using a radioactive beam Rb83 at incident energies 2.4 and 2.7A MeV. The measured an effective relative kinetic energy Ecm=2.393 MeV, which lies within relevant window for core collapse supernovae, is smaller than prediction statistical model calculations. This leads to abu...

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