1,153 research outputs found
Beam-Material Interaction
Th is paper is motivated by the growing importance of better understanding of
the phenomena and consequences of high- intensity energetic particle beam
interactions with accelerator, generic target , and detector components. It
reviews the principal physical processes of fast-particle interactions with
matter, effects in materials under irradiation, materials response, related to
component lifetime and performance, simulation techniques, and methods of
mitigating the impact of radiation on the components and envir onment in
challenging current and future applicationComment: 28 pages, contribution to the 2014 Joint International Accelerator
School: Beam Loss and Accelerator Protection, Newport Beach, CA, USA , 5-14
Nov 201
A new approach to calculate the transport matrix in RF cavities
A realistic approach to calculate the transport matrix in RF cavities is
developed. It is based on joint solution of equations of longitudinal and
transverse motion of a charged particle in an electromagnetic field of the
linac. This field is a given by distribution (measured or calculated) of the
component of the longitudinal electric field on the axis of the linac. New
approach is compared with other matrix methods to solve the same problem. The
comparison with code ASTRA has been carried out. Complete agreement for
tracking results for a TESLA-type cavity is achieved. A corresponding algorithm
will be implemented into the MARS15 code.Comment: 4 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1
Apr 2011. New York, US
Summary of working group g: beam material interaction
For the first time, the workshop on High-Intensity and High-Brightness Hadron
Beams (HB2010), held at Morschach, Switzerland and organized by the Paul
Scherrer Institute, included a Working group dealing with the interaction
between beam and material. Due to the high power beams of existing and future
facilities, this topic is already of great relevance for such machines and is
expected to become even more important in the future. While more specialized
workshops related to topics of radiation damage, activation or thermo -
mechanical calculations, already exist, HB2010 provided the occasion to discuss
the interplay of these topics, focusing on components like targets, beam dumps
and collimators, whose reliability are crucial for a user facility. In
addition, a broader community of people working on a variety of issues related
to the operation of accelerators could be informed and their interest sparked.Comment: 3 pp. 46th ICFA Advanced Beam Dynamics Workshop HB2010, Sep 27 - Oct
1 2010: Morschach, Switzerlan
Towards the optimal energy of the proton driver for a neutrino factory and muon collider
Cross section data from the HARP experiment for pion production by protons
from a tantalum target have been convoluted with the acceptance of the
front-end channel for the proposed neutrino factory or muon collider and
integrated over the full phase space measured by HARP, to determine the
beam-energy dependence of the muon yield. This permits a determination of the
optimal beam energy for the proton driver for these projects. The cross section
data are corrected for the beam-energy dependent amplification due to the
development of hadronic showers in a thick target. The conclusion is that, for
constant beam power, the yield is maximum for a beam energy of about 7 GeV, but
it is within 10% of this maximum for 4<Tbeam < 11 GeV, and within 20% of the
maximum for Tbeam as low as 2 GeV. This result is insensitive to which of the
two HARP groups' results are used, and to which pion generator is used to
compute the thick target effects
Doping of SiC Crystals during Sublimation Growth and Diffusion
The preparation of SiC crystals doped with various impurities introduced during the process of sublimation growth and diffusion is described. The growth of SiC crystals was carried out by a sublimation-sandwich method, proposed by us in 1970. Crystals of the n- and p-type conductivity with maximum content of electrically active impurities (of the order of 1021 cm−3) were obtained. The solubility values of more than 15 impurities were determined. Special tantalum containers with several temperature zones, allowing to introduce any impurity into SiC practically, are developed. The dependences of the impurities concentration on the temperature, growth rate and seed orientation are found. Diffusion of impurities of boron, aluminum, gallium, beryllium, lithium, nitrogen and phosphorus in silicon carbide polytypes was studied. Diffusion coefficients of these impurities in a wide temperature range are determined. It is shown that for a number of impurities diffusion cannot be described by standard distributions that are explained by the presence of several states of diffusing centers. Fast-diffusing states are atoms located in interstices, as well as centers, including the impurity atom and point defect. The extremely low diffusion mobility of lattice point atoms in the SIC lattice is noted
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