245 research outputs found
On the Theory and Simulation of Multiple Coulomb Scattering of Heavy Charged Particles
The Moliere theory of multiple Coulomb scattering is modified to take into
account difference between scattering off atomic nuclei and electron. A simple
analytical expression for angular distribution of charged particles passing
through a thick absorber is found. It does not assume any special form for a
differential cross section and has wider range of applicability than a Gaussian
approximation. A well-known method to simulate multiple Coulomb scattering is
based on the different treatment of soft and hard collisions. An angular
deflection in a large number of soft collisions is sampled using the proposed
distribution function, a small number of hard collisions are simulated
directly. A boundary between hard and soft collisions is defined providing a
precise sampling of scattering angle (1% level) and small number of hard
collisions. A corresponding simulation module takes into account projectile and
nucleus charge distributions and exact kinematics of a projectile-electron
interaction.Comment: 5 pages, 4 figures. Presented paper at the 10th International
Conference on Radiation Shielding, Funchal (Madeira), Portugal, May 9-14,
200
Optimization of the Target Subsystem for the New g-2 Experiment
A precision measurement of the muon anomalous magnetic moment, , was previously performed at BNL with a result of 2.2 - 2.7 standard
deviations above the Standard Model (SM) theoretical calculations. The same
experimental apparatus is being planned to run in the new Muon Campus at
Fermilab, where the muon beam is expected to have less pion contamination and
the extended dataset may provide a possible deviation from the SM,
creating a sensitive and complementary bench mark for proposed SM extensions.
We report here on a preliminary study of the target subsystem where the
apparatus is optimized for pions that have favorable phase space to create
polarized daughter muons around the magic momentum of 3.094 GeV/c, which is
needed by the downstream g 2 muon ring.Comment: 4 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
Energy Deposition Studies for the Hi-Lumi LHC Inner Triplet Magnets
A detailed model of the High Luminosity LHC inner triplet region with new
large-aperture Nb3Sn magnets, field maps, corrector packages, and segmented
tungsten inner absorbers was built and implemented into the FLUKA and MARS15
codes. In the optimized configuration, the peak power density averaged over the
magnet inner cable width is safely below the quench limit. For the integrated
luminosity of 3000 fb -1, the peak dose in the innermost magnet insulator
ranges from 20 to 35 MGy. Dynamic heat loads to the triplet magnet cold mass
are calculated to evaluate the cryogenic capability. In general, FLUKA and MARS
results are in a very good agreement.Comment: 4 pp. Presented paper at the 5th International Particle Accelerator
Conference, June 15 -20, 2014, Dresden, German
Update On The Code Intercomparison and Benchmark For Muon Fluence and Absorbed Dose Induced By An 18-GeV Electron Beam After Massive Iron Shielding
In 1974, Nelson, Kase and Svensson published an experimental investigation on
muon shielding around SLAC high-energy electron accelerators. They measured
muon fluence and absorbed dose induced by 14 and 18 GeV electron beams hitting
a copper/water beamdump and attenuated in a thick steel shielding. In their
paper, they compared the results with the theoretical models available at that
time.
In order to compare their experimental results with present model
calculations, we use the modern transport Monte Carlo codes MARS15, FLUKA2011
and GEANT4 to model the experimental setup and run simulations. The results are
then compared between the codes, and with the SLAC data.Comment: 14 pp. Presented paper at the 13th Meeting of the task-force on
Shielding aspects of Accelerators, Targets and Irradiation Facilities
(SATIF-13), HZDR, October 10-12, 2016, Dresden, Germany. arXiv admin note:
substantial text overlap with arXiv:1502.0168
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