EPAC 2004 - List of Keywords

A B C D E F G H I K L M N O P Q R S T U V W

permanent-magnet

Paper	Title	Other Keywords	Page
MOPKF004	Magnet Sorting Algorithm Applied to the LNLS EPU	undulator, radiation, polarization, wiggler	303
	X.R. Resende, R.M. Dias LNLS, Campinas
	The Brazilian Synchrotron Light Laboratory is about to begin the construction of the first Undulator for its 1.37 GeV electron storage ring. This device will be of the EPU type with a period of 50 milimeters and 22 milimeters minimum magnetic gap. In this work we report on the sorting algorithm applied in the construction of a 10-period undulator prototype.

MOPKF064	Design Considerations for a Helical Undulator for the Production of Polarised Positrons for TESLA	undulator, photon, positron, electron	458
	D.J. Scott, S.C. Appleton, J.A. Clarke, B. Todd CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire E. Baynham, T.W. Bradshaw, S.C. Carr, Y. Ivanyushenkov, J. Rochford CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	An efficient and simple method for the production of positrons, in the necessary quantities, is one of the problems facing proposals for any future e⁺ e^- Linear Collider project. The possibility of colliding polarised beams would also be an advantage. One method to produce a polarised positron beam uses circularly polarised radiation generated by the main electron beam passing through a helical undulator. Design considerations and calculations for two undulators, based on super-conducting and pure permanent magnet technologies, for the TESLA machine, are presented.

MOPKF066	Magnetic Design of a Focusing Undulator for ALPHA-X	undulator, focusing, electron, quadrupole	464
	B.J.A. Shepherd, J.A. Clarke CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
	ALPHA-X is a four-year project shared between several research groups in the UK to build a laser-plasma accelerator and produce coherent short-wavelength radiation in an FEL. The FEL undulator will be a 1.5m long, 100 period permanent magnet device with a minimum gap of 3.5mm and a peak field of 0.7T. To focus the beam inside the undulator, several schemes were examined. In the scheme that was selected, the magnet blocks are designed so that the pole face is an approximation of a parabola. This focuses the beam horizontally and vertically. The magnetic design of the undulator is complete; design of the support structure is well under way. Test pieces have been built to ensure that the clamping arrangement is strong enough to cope with the magnetic forces involved. The complete undulator will be built in late 2004 at Daresbury Laboratory, and tested on-site in the new magnet test facility.

MOPLT103	Radiation Resistant Magnetic Sensors for Accelerators	radiation, monitoring, electron, background	773
	I. Bolshakova, R. Holyaka LPNU, Lviv S. Kulikov JINR, Dubna, Moscow Region M. Kumada NIRS, Chiba-shi C. Leroy Université de Montréal, Groupe de la Physique des Particules, Montréal, Québec
	The technology of obtaining the radiation resistant magnetic sensors, which characteristics remain stable under the irradiation with high dose of fast neutrons was designed. Radiation resistant sensors are developed on the base of InSb. While irradiation with neutron flux of 10¹⁰ ncm-2c-1 with energies 0.1…13�MeV, with the thermal neutrons part in the general flux of 20% and intermediate fluxes of 25%, the main sensors’ characteristics, that is their sensitivity to the magnetic field, change no more than for 0.05% up to the fluence of 110¹⁵ ncm-2 and no more than for 1% up to the fluence of 310¹⁶ ncm-2. Radiation resistant sensors are used for development of magnetic field monitoring system with measuring channels accuracy of 0,01%, which have a function of temperature measurement with the accuracy of 0.1�С at the place of sensor location, moreover, it has self diagnostics and self correction functions. This system passed the long-term testing of continuous 3 months operation at the Neutron Physics Laboratory, JINR, Dubna at the IBR-2 neutron reactor.

MOPLT141	IR Upgrade Plans for the PEP-II B-Factory	luminosity, interaction-region, beam-beam-effects, dipole	869
	M.K. Sullivan, S. Ecklund, N. Kurita, A. Ringwall, J. Seeman, U. Wienands SLAC, Menlo Park, California M.E. Biagini INFN/LNF, Frascati (Roma)
	PEP-II, the SLAC, LBNL, LLNL B-factory has achieved a peak luminosity of over 7e33, more than twice the design luminosity, and plans to obtain a luminosity of over 1·10³⁴ in the next year. In order to push the luminosity performance of PEP-II to even higher levels an upgrade to the interaction region is being designed. In the present design, the interaction point is a head-on collision with two strong horizontal dipole magnets (B1) located between 20-70 cm from the IP that bring the beams together and separate the beams after the collision. The first parasitic crossing (PC) is at 63 cm from the IP in the present by2 bunch spacing. The B1 magnets supply all of the beam separation under the present design. Future improvements to PEP-II performance include lowering the beta y * values of both rings. This will increase the beta y value at the PCs which increases the beam-beam effect at these non-colliding crossings. Introducing a horizontal crossing angle at the IP quickly increases the beam separation at the PCs but recent beam-beam studies indicate a significant luminosity reduction occurs when a crossing angle is introduced at the IP. We will discuss these issues and describe the present interaction region upgrade design.

WEPKF033	Application of Finite Volume Integral Approach to Computing of 3D Magnetic Fields Created by Distributed Iron-dominated Electromagnet Structures	undulator, dipole, insertion-device, insertion	1675
	O.V. Chubar, C. Benabderrahmane, O. Marcouillé, F. Marteau SOLEIL, Gif-sur-Yvette J. Chavanne, P. Elleaume ESRF, Grenoble
	Iron-dominated electromagnet structures are traditionally considered as a domain of applications of the Finite-Element Method (FEM). FEM computer codes provide high accuracy for "close circuit" type geometries, however they are much less efficient for distributed geometries consisting of many spatially separated magnets interacting with each other. Examples of such geometries related to particle accelerators are insertion devices, quadrupole and sextupole magnets located close to each other, magnets with combined functions. Application of the finite volume integral approach implemented in the Radia 3D magnetostatics code to solving such geometries is described. In this approach, space around individual magnets does not require any meshing. An adaptive segmentation of iron parts, with the segmenting planes being roughly perpendicular or parallel to the expected directions of magnetic flux lines, minimizes dramatically the necessary CPU and memory resources. If a geometry is, nevertheless, too big for its complete interaction matrix to fit into memory, a special scheme of relaxation "by parts" can be applied. The results of calculations made for the SOLEIL electromagnet undulator HU256 will be presented.

WEPKF041	Permanent Magnet Generating High and Variable Septum Magnetic Field and its Deterioration by Radiation	radiation, septum, booster, beam-losses	1696
	T. Kawakubo, E. Nakamura, M. Numajiri KEK, Ibaraki M. Aoki, T. Hisamura, E. Sugiyama NEOMAX Co., Ltd., Mishima-gun, Osaka
	Conventional high field septum magnet is fed by DC current or pulse current. In the case of DC, the problem of coil support is not very important, but the cooling of the coil is serious problem. While, in the case of pulse, the problem of support is much important than that of cooling. However, if the septum magnet is made of permanent magnet, those problems are dissolved. And the cost for electricity and cooling water can be exceedingly decreased. Therefore, we made the model septum magnet which has 1/4 scale of the real size and generates 1[T] with the variable range of ± 10%. The magnetic field distribution in the gap by changing the representative field is reported. When this permanent magnet is set in an accelerator, the deterioration of the permanent magnet by radiation will be serious problem. We also report the dependence of the magnetic fields generated by permanent magnet samples on accumulated radiation by various types of radiation source.

WEPKF047	A Super Strong Adjustable Permanent Magnet for the Final Focus Quadrupole in a Linear Collider	quadrupole, linear-collider, collider, simulation	1708
	T. Mihara, Y. Iwashita Kyoto ICR, Uji, Kyoto E. Antokhin, M. Kumada NIRS, Chiba-shi C.M. Spencer SLAC, Menlo Park, California E. Sugiyama NEOMAX Co., Ltd., Mishima-gun, Osaka
	A super strong magnet, which utilizes permanent magnet material and saturated iron, is considered as a candidate for the final focus quadrupole in a linear collider beamline. This modified Halbach magnet configuration can have a higher magnetic field gradient than a normal permanent magnet quadrupole (PMQ) or electromagnet. There are some issues to be solved if a PMQ is to be used as a final focus quadrupole: the variation of its strength with temperature and the need for the field strength to be deliberately changed. One can use special temperature compensation material to improve the temperature dependence with just a small decrease in field gradient compared to a magnet without temperature compensation. The required field variability can be obtained by slicing the magnet into pieces along the beamline direction and rotating these slices. Results of performance measurements on the PMQ with variable strength will be reported including the realization of the temperature compensation technique.

WEPKF082	Radiation Damage Studies with Hadrons on Materials and Electronics	radiation, multipole, radioactivity, hadron	1795
	J.E. Spencer, J. Allan, S. Anderson, R. Wolf SLAC, Menlo Park, California M. Boussoufi UCD/MNRC, McClellan, California D.E. Pellet UCD, Davis J.T. Volk Fermilab, Batavia, Illinois
	Many materials and electronic devices need to be tested for the radiation environment expected at the proposed linear colliders (LC) where the accelerator and detectors will be subjected to large fluences of hadrons, electrons and gammas during the life of the facility. Examples are NdFeB permanent magnets which are being considered for the damping rings and final focus, electronic and electro-optical devices which will be utilized in the detector readout and accelerator control systems and CCDs required for the vertex detector. The effects of gammas on a broad range of materials was presented at NSREC2002 and our understanding of the current situation concerning rare earth permanent magnets at PAC2003 where a program was proposed using neutrons from the McClellan Nuclear Reactor Center (MNRC) that has a number of areas for irradiating samples with neutron fluxes up to 4.5·10¹³ n/cm2s. A specialized area allows irradiation with 1 MeV-equivalent neutrons with fluxes of 4.2·10¹⁰ n/cm2s while suppressing thermal neutrons and gammas by large factors. We give our latest results and their interpretation using this facility.

WEPLT103	Radiation Damage in Magnets for Undulators at Low Temperature	radiation, electron, undulator, linac	2092
	T. Bizen, X. Maréchal, T. Seike JASRI/SPring-8, Hyogo Y. Asano JAERI/SPring-8, Hyogo T. Hara, H. Kitamura, T. Tanaka RIKEN Spring-8 Harima, Hyogo D.E. Kim, H.S. Lee PAL, Pohang
	Nd2Fe14B permanent magnets are used in many insertion devices for its good magnetic and mechanical properties. However, the radiation sensitivity of the magnets would be concern when they are used in a strong radiation environment. It is known that these magnets with very high coercivity show high resistance to radiation, though the substance for increasing the coercivity decrease the remanence. The coercivity and remanence of this magnet exhibit negative dependence against temperature, so it is expected to these magnets to show high remanence and high resistance to radiation at low temperature. The idea of using magnets at low temperature leads the new concept of the cryogenic undulators. In this report, the experimental results of the radiation damage of permanent magnets at low temperature are shown.