374 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
Ultra-Fast Hadronic Calorimetry
Calorimeters for particle physics experiments with integration time of a few
ns will substantially improve the capability of the experiment to resolve event
pileup and to reject backgrounds. In this paper the time development of
hadronic showers induced by 30 and 60 GeV positive pions and 120 GeV protons is
studied using Monte Carlo simulation and beam tests with a prototype of a
sampling steel-scintillator hadronic calorimeter. In the beam tests,
scintillator signals induced by hadronic showers in steel are sampled with a
period of 0.2 ns and precisely time-aligned in order to study the average
signal waveform at various locations with respect to the beam particle impact.
Simulations of the same setup are performed using the MARS15 code. Both
simulation and test beam results suggest that energy deposition in steel
calorimeters develop over a time shorter than 2 ns providing opportunity for
ultra-fast calorimetry. Simulation results for an "ideal" calorimeter
consisting exclusively of bulk tungsten or copper are presented to establish
the lower limit of the signal integration window.Comment: 10 pages, 16 figures, accepted for publication in NIM
Detector Background at Muon Colliders
Physics goals of a Muon Collider (MC) can only be reached with appropriate
design of the ring, interaction region (IR), high-field superconducting
magnets, machine -detector interface (MDI) and detector. Results of the most
recent realistic simulation studies are presented for a 1.5-TeV MC. It is shown
that appropriately designed IR and MDI with sophisticated shielding in the
detector have a potential to substantially suppress the background rates in the
MC detector. The main characteristics of backgrounds are studied.Comment: 8 pp. 2nd International Conference on Technology and Instrumentation
in Particle Physics 2011: TIPP 2011, 9-14 Jun 2011: Chicago, Illinoi
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
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