99,080 research outputs found
Machine Protection
The protection of accelerator equipment is as old as accelerator technology
and was for many years related to high-power equipment. Examples are the
protection of powering equipment from overheating (magnets, power converters,
high-current cables), of superconducting magnets from damage after a quench and
of klystrons. The protection of equipment from beam accidents is more recent.
It is related to the increasing beam power of high-power proton accelerators
such as ISIS, SNS, ESS and the PSI cyclotron, to the emission of synchrotron
light by electron-positron accelerators and FELs, and to the increase of energy
stored in the beam (in particular for hadron colliders such as LHC). Designing
a machine protection system requires an excellent understanding of accelerator
physics and operation to anticipate possible failures that could lead to
damage. Machine protection includes beam and equipment monitoring, a system to
safely stop beam operation (e.g. dumping the beam or stopping the beam at low
energy) and an interlock system providing the glue between these systems. The
most recent accelerator, the LHC, will operate with about 3x10 14 protons per
beam, corresponding to an energy stored in each beam of 360 MJ. This energy can
cause massive damage to accelerator equipment in case of uncontrolled beam
loss, and a single accident damaging vital parts of the accelerator could
interrupt operation for years. This article provides an overview of the
requirements for protection of accelerator equipment and introduces the various
protection systems. Examples are mainly from LHC, SNS and ESS.Comment: 23 pages, contribution to the CAS - CERN Accelerator School: Advanced
Accelerator Physics Course, Trondheim, Norway, 18-29 Aug 201
Machine Protection and Interlock Systems for Circular Machines - Example for LHC
This paper introduces the protection of circular particle accelerators from
accidental beam losses. Already the energy stored in the beams for accelerators
such as the TEVATRON at Fermilab and Super Proton Synchrotron (SPS) at CERN
could cause serious damage in case of uncontrolled beam loss. With the CERN
Large Hadron Collider (LHC), the energy stored in particle beams has reached a
value two orders of magnitude above previous accelerators and poses new threats
with respect to hazards from the energy stored in the particle beams. A single
accident damaging vital parts of the accelerator could interrupt operation for
years. Protection of equipment from beam accidents is mandatory. Designing a
machine protection system requires an excellent understanding of accelerator
physics and operation to anticipate possible failures that could lead to
damage. Machine protection includes beam and equipment monitoring, a system to
safely stop beam operation (e.g. extraction of the beam towards a dedicated
beam dump block or stopping the beam at low energy) and an interlock system
providing the glue between these systems. This lecture will provide an overview
of the design of protection systems for accelerators and introduce various
protection systems. The principles are illustrated with examples from LHC.Comment: 23 pages, contribution to the 2014 Joint International Accelerator
School: Beam Loss and Accelerator Protection, Newport Beach, CA, USA , 5-14
Nov 201
Bidirectional zoom antenna
Antenna comprises two parabolic cylinders placed orthogoanlly to each other. One cylinder serves as main reflector, and the other as subreflector. Cylinders have telescoping sections to vary antenna beamwidth. Beamwidth can be adjusted in elevation, azimuth, or both. Design has no restriction as to choice of polarization
An improvement in blackbody cavity design
Setting the axis of the conical cavity at an angle to the axis of observation removes the imperfection at the apex of the cone from the direct observation area of the radiometer. Fillet no longer behaves as a nonuniformity in the blackbody
Electronic scanning of 2-channel monopulse patterns
Scanning method involves separation of scanning capability into two independent degrees of freedom. One degree of freedom corresponds to azimuthal scanning and other to elevation scanning on spiral coordinate axes. Scanning of both prime-feed and mirrored patterns is accomplished with reduction of mechanical vibration damage to large antennas
Electronic scanning of 2-channel monopulse patterns Patent
Monopulse scanning network for scanning volumetric antenna patter
Dish antenna having switchable beamwidth
A switchable beamwidth antenna includes a concave parabolic main reflecting dish which has a central circular region and a surrounding coaxial annular region. A feed means selectively excites only the central region of the main dish via a truncated subreflector for wide beamwidth or substantially the entire main dish for narrow beamwidth. In one embodiment, the feed means comprises a truncated concave ellipsoid subreflector and separate feed terminations located at two foci of the ellipsoid. One feed termination directly views all of the main dish while the other feed termination, exciting the main dish via the subreflector, excites only the central region because of the subreflector truncation. In the another embodiment, the feed means comprises one feed termination and a convex hyperboloid subreflector via which the feed excites the main dish
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