skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Development of a 3.8 Meter Variable Polarization Undulator (EPU)

Abstract

The design of a Variable Polarization Undulator (EPU) of the four row, pure permanent magnet undulator and a length of 3.8 m is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and magnetic considerations that influenced the design are then analyzed. This undulator will be installed on a new beam line for materials science research, designated BL13 at Stanford Synchrotron Radiation Laboratory (SSRL) BL13 is being designed for the photon energy range from 250 to 1600 eV, and to utilize an undulator source that produces linear polarized radiation at variable azimuthal angles as well as both left and right circularly and elliptically polarized radiation.

Authors:
; ; ;  [1]; ;  [2];
  1. Advanced Design Consulting USA, 126 Ridge Road, P.O. Box 187, Lansing, NY 14882 (United States)
  2. Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)
Publication Date:
OSTI Identifier:
21052535
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 879; Journal Issue: 1; Conference: 9. international conference on synchrotron radiation instrumentation, Daegu (Korea, Republic of), 28 May - 2 Jun 2006; Other Information: DOI: 10.1063/1.2436082; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 43 PARTICLE ACCELERATORS; BEAM PRODUCTION; DESIGN; EV RANGE; PERMANENT MAGNETS; PHOTON BEAMS; PHOTONS; POLARIZATION; POLARIZED BEAMS; SYNCHROTRON RADIATION; WIGGLER MAGNETS

Citation Formats

Deyhim, Alex, Lyndaker, Aaron, Waterman, Dave, Caletka, Dave, Rowen, Michael, Rabedeau, Thomas, and Blomqvist, K. Ingvar. Development of a 3.8 Meter Variable Polarization Undulator (EPU). United States: N. p., 2007. Web. doi:10.1063/1.2436082.
Deyhim, Alex, Lyndaker, Aaron, Waterman, Dave, Caletka, Dave, Rowen, Michael, Rabedeau, Thomas, & Blomqvist, K. Ingvar. Development of a 3.8 Meter Variable Polarization Undulator (EPU). United States. doi:10.1063/1.2436082.
Deyhim, Alex, Lyndaker, Aaron, Waterman, Dave, Caletka, Dave, Rowen, Michael, Rabedeau, Thomas, and Blomqvist, K. Ingvar. Fri . "Development of a 3.8 Meter Variable Polarization Undulator (EPU)". United States. doi:10.1063/1.2436082.
@article{osti_21052535,
title = {Development of a 3.8 Meter Variable Polarization Undulator (EPU)},
author = {Deyhim, Alex and Lyndaker, Aaron and Waterman, Dave and Caletka, Dave and Rowen, Michael and Rabedeau, Thomas and Blomqvist, K. Ingvar},
abstractNote = {The design of a Variable Polarization Undulator (EPU) of the four row, pure permanent magnet undulator and a length of 3.8 m is presented. The design requirements and mechanical difficulties for holding, positioning, and driving the magnetic arrays are explored. The structural and magnetic considerations that influenced the design are then analyzed. This undulator will be installed on a new beam line for materials science research, designated BL13 at Stanford Synchrotron Radiation Laboratory (SSRL) BL13 is being designed for the photon energy range from 250 to 1600 eV, and to utilize an undulator source that produces linear polarized radiation at variable azimuthal angles as well as both left and right circularly and elliptically polarized radiation.},
doi = {10.1063/1.2436082},
journal = {AIP Conference Proceedings},
number = 1,
volume = 879,
place = {United States},
year = {Fri Jan 19 00:00:00 EST 2007},
month = {Fri Jan 19 00:00:00 EST 2007}
}
  • The design of a high end, very sophisticated controller, that consists of an Allen Bradley ControlLogix PLC with a Kinetix servo controller for a 4.16 m EPU is presented. Four servo motors control the gap - 2 on the upper girder and 2 on the lower girder, and another 4 servos controls the phase - 2 on the upper girder inner and outer and 2 on the lower girder, inner and outer. This system is designed for The Taiwan Light Source (TLS) a synchrotron radiation machine of the National Synchrotron Radiation Research Center (NSRRC) at the energy of 1.5 GeVmore » with electron beam current of 200 {approx} 400 mA.« less
  • The soft x-ray beamline 5U1 on the Daresbury Laboratory SRS currently uses a planar undulator, producing linearly polarized radiation in the range 100 to 1000 eV. The undulator is soon to be replaced by a variable-polarization device of the Apple II design. The aim is to produce circularly polarized light in the energy range 265 to 1000 eV, covering the K-edges of C, N and O, and the first row transition element L-edges. This will greatly enhance the provision of circularly polarized soft-x-rays on the SRS and open up new opportunities for experimenters. The device will also produce linear polarizationmore » with a selectable angle of polarization with respect to the orbit plane, which is currently unavailable on the SRS. In order to provide the coverage over this energy range, we are exploiting the relatively large emittance of the SRS to allow us to use the second and third harmonics even in circular polarization mode. This paper presents the expected beamline output in various polarization modes and the predicted degree of polarization.« less
  • An integrated system to produce and utilize variable-polarization radiation from a crossed undulator source on the Aladdin storage ring is being designed in a multilaboratory collaboration. Brief discussions of the motivation and options available precede a description of the source. Comments on ongoing work are also presented.
  • We have reanalyzed data from observations of PSR B1706-44, SN 1006, and the Vela pulsar region made with the CANGAROO 3.8 m Imaging Atmospheric Cherenkov Telescope between 1993 and 1998 in response to the results reported for these sources by the H.E.S.S. Collaboration. Although detections of TeV gamma-ray emission from these sources were claimed by CANGAROO more than 10 years ago, upper limits to the TeV gamma-ray signals from PSR B1706-44 and SN 1006 derived by H.E.S.S. are about an order of magnitude lower. The H.E.S.S. group detected strong diffuse TeV gamma-ray emission from Vela but with a morphology differingmore » from the CANGAROO result. In our reanalysis, in which gamma-ray selection criteria have been determined exclusively using gamma-ray simulations and OFF-source data as background samples, no significant TeV gamma-ray signals have been detected from compact regions around PSR B1706-44 or within the northeast rim of SN 1006. The upper limits to the integral gamma-ray fluxes at the 95% confidence level have been estimated for the 1993 data of PSR B1706-44 to be F(>3.2 {+-} 1.6 TeV) < 8.03 x 10{sup -13} photons cm{sup -2} s{sup -1}, for the 1996 and 1997 data of SN 1006 to be F(>3.0 {+-} 1.5 TeV) < 1.20 x 10{sup -12} photons cm{sup -2} s{sup -1} and F(>1.8 {+-} 0.9 TeV) < 1.96 x 10{sup -12} photons cm{sup -2} s{sup -1}, respectively. We discuss reasons why the original analyses gave the source detections. The reanalysis did result in a TeV gamma-ray signal from the Vela pulsar region at the 4.5{sigma} level using 1993, 1994, and 1995 data. The excess was located at the same position, 0.{sup 0}13 to the southeast of the Vela pulsar, as that reported in the original analysis. We have investigated the effect of the acceptance distribution in the field of view of the 3.8 m telescope, which rapidly decreases toward the edge of the field of the camera, on the detected gamma-ray morphology. The expected excess distribution for the 3.8 m telescope has been obtained by reweighting the distribution of HESS J0835-455 measured by H.E.S.S. with the acceptance of the 3.8 m telescope. The result is morphologically comparable to the CANGAROO excess distribution, although the profile of the acceptance-reweighted H.E.S.S. distribution is more diffuse than that of CANGAROO. The integral gamma-ray flux from HESS J0835-455 has been estimated for the same region as defined by H.E.S.S. from the 1993-1995 data of CANGAROO to be F(>4.0 {+-} 1.6 TeV) = (3.28 {+-} 0.92) x 10{sup -12} photons cm{sup -2} s{sup -1}, which is statistically consistent with the integral flux obtained by H.E.S.S.« less
  • A novel undulator has been developed for the soft X-ray beamline BL17SU of SPring-8. Experiments to be done at the BL17SU require linearly/circularly polarized light and fast helicity switching of circular polarized light. In addition, it must have low power density on axis to avoid a heat load problem. Therefore, the undulator has three operation modes; it works as a helical undulator for circular polarized light, figure-8 undulator for linear polarized light and asymmetric figure-8 undulator for fast helicity switching. In order to realize three types of undulator, the novel undulator consists of electromagnets and permanent magnets. The magnetic fieldmore » has been measured at each operation mode and performances have been calculated from the measurement results.« less