2011 Particle Accelerator Conference - Classification: Accelerator Technology / Tech 15: Insertion Devices (Undulators and Wigglers)

Paper

Title

Page

Super-Conducting Wigglers and the Effect on Injection Efficiency

1259

M.J. Sigrist, L.O. Dallin, W.A. Wurtz
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source has two superconducting wigglers (SCW) operating at 2.1T and 4.3T peak fields. Injection efficiency into the storage ring is reduced by either device operating at high fields. Currently the CLS operates with a Fill and Decay mode, injecting with both wigglers at reduced field to avoid low injection efficiencies. Future implementation of a Top-up mode will require both wigglers to be operating at full field and better injection efficiencies will be required. Simulations and experiments have shown that the poor injection efficiency is related to operating a high vertical chromaticity. Much improved efficiencies are observed at when the chromaticity is lowered. As well, small improvements to the injection efficiency have been achieved through local correction of the beta-beats and tune shifts caused by the wigglers and optimisation of the injection co-ordinates of the injected beam. Measurements of the injection efficiencies at various chromaticities will be presented along with the betatron oscillations before and after correction.

TUP235

Strategy for Neutralizing the Impact of Insertion Devices on the MAX IV 3 GeV Ring

1262

E.J. Wallén, S.C. Leemann
MAX-lab, Lund, Sweden

In order to prepare for the potentially negative influence on the beam lifetime, injection efficiency and beam size from the insertion devices (IDs) on the stored beam of the MAX IV 3 GeV storage ring strategy for neutralizing the foreseen effects of the IDs has been developed. In short the strategy involves a local correction of the betatron phase advance by adjusting the strength of the quadrupoles adjacent to the ID. There will also be a global tune correction in order to avoid drift in the working point of the storage ring during operation. Air coils with empirical feed forward tables for the excitation current in the coils will compensate for field integral errors. The lattice of the MAX IV 3 GeV storage ring appears to be robust and it tolerates the dynamic multipoles created by the expected initial set of IDs provided that the local correction of the betatron phase advance has been carried out.

TUP236

Progress of a Gradient Damping Wiggler of the ALPHA Storage Ring

1265

C.W. Huang, D.J. Huang
NTHU, Hsinchu, Taiwan
S.D. Chen
NCTU, Hsinchu, Taiwan
M.-H. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, Y.T. Yu
NSRRC, Hsinchu, Taiwan
S.-Y. Lee
IUCF, Bloomington, Indiana, USA

The main purpose of a gradient damping wiggler (GDW) to be installed in the Alpha storage ring in Indiana University is to correct the momentum-compaction factor and the damping partition in the Alpha storage ring. One middle pole and two outer poles in one set of the GDW are installed on the same girder. Two sets of GDW will be installed in the two short straight sections. The dipole and gradient-field strengths of the middle (outer) pole are 0.67 T (-0.67 T) and 1.273 T m^-1 (1.273 T m^-1), respectively. One completed set of GDW is already fabricated; we shall add an end shim to improve the region of effective good field within which the middle and outer poles along the transverse x-axis (△B/B = 0.1 %) are ±50 and ±40 mm respectively. We used a trim coil on the three poles to adjust the first and second integral fields to zero. Here we discuss the integral magnetic field features along the straight trajectory and the ideal orbital trajectory with a Hall probe mapping system, and present an analysis of the magnetic field.

TUP237

Development of Accurate and Precise In-Vacuum Undulator System

1268

A. Deyhim, J.D. Kulesza
Advanced Design Consulting, Inc, Lansing, New York, USA
K.I. Blomqvist
MAX-lab, Lund, Sweden

Typical in-vacuum undulators, especially long ones, have several associated engineering challenges to be accurate and precise; magnetic centerline stability, inner girder hangers, and magnet period to name a few. The following describes these issues in more detail and ADC’s methods solved these critical issues for long in vacuum undulators. ADC has designed, built and delivered Insertion Devices and Magnetic Measurement Systems to such facilities as; MAXLab (EPU, Planar-2, and Measurement System), ALBA and Australian Synchrotron Project (Wiggler), BNL (Cryo In-Vacuum), SSRF (In-Vacuum – 2, and Measurement System), PAL (In-Vacuum and Measurement System), NSRRC (In-Vacuum), and SRC (Planar and EPU). The information presented here uses data from a recent IVU we delivered to PAL. This IVU will be installed at Pohang Accelerator Laboratory (PAL) for U-SAXS (Ultra Small Angle X-ray Scattering) beamline in 2011. The IVU generates undulator radiation up to ~14 keV using higher harmonic (up to 9th) undulator radiation with 2.5 GeV PLS electron beam

TUP238

Development of an Integrated Field Measurement System (IFMS) for NSLS II

1271

A. Deyhim, S.W. Hartman, J.D. Kulesza
Advanced Design Consulting, Inc, Lansing, New York, USA

This paper describes the mechanical design, control instrumentation and software for the Integrated Field Measurement System (IFMS) for the Magnetic Measurement Lab for the National Synchrotron Light Source II (NSLS-II) project at Brookhaven National Laboratory. Insertion devices (IDs) at NSLS II need to be accurately surveyed using an integrated field measurement system prior to insertion into the storage ring and can also be used in the tunnel for final tuning of IDs. It is a fast and precise measurement system required in determining the ID magnetic field integrals. The design is a set of long coils supported by two 3-axis X-Y-Z precision linear and two precision rotary positioning stages. The PC is the primary control unit. Eight stepping motor control cards, eight drivers, one digital I/O board, one 6U PXI card, and one integrator are installed to perform remote control and data acquisition.

TUP239

Development of a Super-Mini Undulator

1274

A. Deyhim, J.D. Kulesza
Advanced Design Consulting, Inc, Lansing, New York, USA
C. Diao, H.O. Moser
SSLS, Singapore, Singapore

This paper describes development and initial results for a small prototype of a superconducting undulator with a period less than 1 cm, referred to here as a “super-mini” undulator. The development of superconducting mini-undulators started in the early 1990s with work at BNL and KIT (Germany). In 1998, KIT demonstrated the first photon production with a super-mini of 3.8 mm period length *. This super-mini consisted of two coils wound bi-filarly in analogy to a solenoid. If such coils are arranged alongside each other, separated only by a small gap of the order of a couple of millimeters, a spatially alternating magnetic field is produced that makes a passing electron beam undulate and emit undulator radiation. Owing to the short period length, the photon energy is much higher than with conventional undulators at the same electron energy. Likewise, for a given photon energy, the electron energy can be much smaller entailing considerable cost savings of accelerator, building, and operations.
* T. Hezel, B. Krevet, H.O. Moser, J.A. Rossmanith, R. Rossmanith, and Th. Schneider, A superconductive undulator with a period length of 3.8 mm, J. Synchrotron Rad. 5(1998) pp. 448-450.

TUP240

Coil Energizing Patterns for an Electromagnetic Variably Polarizing Undulator

1277

R.J. Dejus, M.S. Jaski, E.R. Moog
ANL, Argonne, USA
S. Sasaki
HSRC, Higashi-Hiroshima, Japan

Funding: The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”).
A new electromagnetic insertion device optimized for producing intense soft x-rays of variable polarization is under construction at the Advanced Photon Source. Most of the coil packs are powered by a main power supply; a few are powered separately so that magnetic fields at certain pole positions can be different. The undulator radiation depends sensitively on the chosen magnetic field pattern, and higher spectral harmonics may be shifted in energy. For some beamline experiments, it is important to reduce the so-called higher-order contamination to increase the signal-to-noise ratio. We present spectra and power densities calculated directly from realistic magnetic fields and discuss coil energizing patterns.
Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

TUP241

End-Field Analysis and Implementation of Correction Coils for a Short-Period NbTi Superconducting Undulator

1280

C.L. Doose, M. Kasa, S.H. Kim
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A short period superconducting undulator (SCU) is being developed at the Advanced Photon Source (APS). The on-axis field of the prototype 1.6-cm period 42-pole SCU0 was measured with a cryogenic Hall probe system. Typical permanent magnet undulators provide end-field correction by decreasing the strength of the magnets on both ends of each jaw. In the case of the SCU0, a set of correction coils was wound on the two end grooves of each of the steel cores along with the main coils to provide the required end fields. These correction coils were connected in series and energized with one power supply to provide simple and symmetrical operation. The measured phase errors of the SCU0 were below 2 degrees rms without any local magnetic tuning of the device.

TUP242

Electron Cloud Issues for the APS Superconducting Undulator

1283

K.C. Harkay, Y. Ivanyushenkov, R. Kustom, E.R. Moog, E. Trakhtenberg
ANL, Argonne, USA
L.E. Boon, A.F. Garfinkel
Purdue University, West Lafayette, Indiana, USA

Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS Upgrade calls for the development and commissioning of a superconducting undulator (SCU) at the Advanced Photon Source (APS), a 7-GeV electron synchrotron. Operation of an SCU at Angstromquelle Karlsruhe (ANKA), also an electron ring, suggests that electron multipacting is consistent with the observed heat load and pressure rise, but this effect is not predicted by an electron cloud generation code. At APS it was found that while the cloud code POSINST agreed fairly well with retarding field analyzer (RFA) data for a positron beam (operated 1996-98), the agreement was less satisfactory for the electron beam. The APS data suggest that the photoelectron model is not complete. Given that the heat load is a critical parameter in designing the cryosystem for the SCU and given the experience at ANKA, a study is underway to minimize the possible contribution to the heat load by the electron cloud at the APS, the photoelectrons in particular. In this talk, the results from POSINST are presented. Preliminary tracking of the photon flux using SYNRAD3D for the APS SCU chamber is presented, and possible ways to mitigate the photoelectrons are discussed.

TUP243

Development Status of a Magnetic Measurement System for the APS Superconducting Undulator

1286

Y. Ivanyushenkov, M. Abliz, C.L. Doose, M. Kasa, E. Trakhtenberg, I. Vasserman
ANL, Argonne, USA
V.K. Lev, N.A. Mezentsev, V.M. Tsukanov
BINP SB RAS, Novosibirsk, Russia

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
Short-period superconducting undulators are being developed as part of the Advanced Photon Source (APS) upgrade program. The first test device is in fabrication. Before installation into the storage ring, the magnetic performance of the undulators will be characterized. The magnetic measurement facility routinely used for measuring and tuning conventional undulators cannot be employed for superconducting devices, so a new measurement system is being designed and built. The system is mechanically mounted on the undulator cryostat and uses a heated tube in the cold undulator bore to guide a Hall probe or measuring coils. A specially designed three-Hall sensor assembly allows measurement of the vertical and horizontal components of the magnetic field and the determination of the height of the magnetic midplane. A set of measuring coils is mounted on carbon-fiber tubes that can be translated and rotated in the undulator bore to measure the field integrals and their multipole components. The design of the measurement system and its construction status is described in this paper.

TUP244

Magnetic Simulation of an Electromagnetic Variably Polarizing Undulator *

1289

M.S. Jaski, R.J. Dejus, E.R. Moog
ANL, Argonne, USA

Development of an all-electromagnetic variable polarizing undulator is underway at the Advanced Photon Source (APS). This device has a set of Bx poles and coils and a set of By poles and coils. The Bx coils are powered separately from the By coils. Modifying the geometry of the Bx coils or poles changes not only the Bx field but changes the By field as well and vice-versa. Magnetic modeling with OPERA 3-D software was used to optimize the coil and pole geometries. Results of the magnetic field simulation and optimization are presented in this paper.
* Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC02-06CH11357.

TUP245

Comparison of Standard S-Glass and Ceramic Coating as Insulation in Short-Period Superconducting Undulators Based on Nb3Sn

1292

S.H. Kim, C.L. Doose, M. Kasa, R. Kustom, E.R. Moog
ANL, Argonne, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
This paper compares calculated on-axis fields for short- period superconducting undulators (SCUs) using Nb3Sn superconductor with two different insulation thicknesses, 0.02 mm and 0.05 mm. When the insulated conductor diameter remained the same, the on-axis fields using the thinner insulation were higher by about 8 – 15% for a period range of 15 – 10 mm. When the conductor diameters with the thicker insulation were made larger than the conductors with the thinner insulation, the differences were reduced to be about 6 – 12%.

TUP248

SC Undulator with the Possibility To Change Its Strength and Polarization by Feeding Current

1295

A.A. Mikhailichenko
CLASSE, Ithaca, New York, USA

Funding: NSF
We describe the design of optimized undulator with SC windings able to generate the magnetic field of opposite helicities, including an elliptic and a linear ones oriented as desired. For the undulator period 25mm and aperture 8mm, K factor could be changed from zero up to 1.5 by changing the feeding current. Polarization changed by changing the currents in additional helical windings.

THOBS1

Developments in Superconducting Insertion Devices

2077

E.R. Moog, Y. Ivanyushenkov
ANL, Argonne, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A number of superconducting wigglers are installed and in operation worldwide. Superconducting undulators, with their shorter periods and more demanding field quality requirements, present additional challenges and are still under development. Superconducting technology can produce a higher magnetic field strength on the beam axis than can a permanent-magnet-based undulator. This makes shorter period undulators feasible – they will still reach high enough field to have a reasonable photon energy tuning range. The shorter period device gives higher photon brightness at higher photon energies, opening up new opportunities for photon-hungry applications that require higher photon energies. Many light sources are interested in having a superconducting undulator; a few, including the Advanced Photon Source, have ongoing projects and are making significant progress. The status of these projects will be discussed.

Slides THOBS1 [3.427 MB]

THOBS4

Current Status of Insertion Device Development at the NSLS-II and its Future Plans

2090

T. Tanabe, O.V. Chubar, T.M. Corwin, D.A. Harder, P. He, C.A. Kitegi, G. Rakowsky, J. Rank, C. Rhein, C.J. Spataro
BNL, Upton, Long Island, New York, USA

Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH1-886 with the U.S. Department of Energy.
National Synchrotron Light Source-II (NSLS-II) project is currently under construction. Procurement of various insertion devices (IDs) has begun. IDs in the project baseline scope include six 3.5m long damping wigglers (DWs) with 100mm period, two 2.0m Elliptically Polarizing Undulator (EPU) with 49mm period, two 3.0m-20mm period IVUs and one 1.5m-21mm IVU. Recently a special device for inelastic X-ray scattering beamline has been added to the collection of baseline devices. This is a special wide pole IVU with 22mm period for a long straight section. Three pole wigglers with 28mm gap and peak field over 1T will be utilized for NSLS bending magnet users. Examples of R&D work for future devices are: 1) Development of in-vacuum magnetic measurement system (IVMMS), 2) Use of new type of magnet such as PrFeB for improved performance on cryo-permanent magnet undulator (CPMU), 3) Development of closed loop He gas refrigerator with a linear motor actuator, 4) Adaptive gap undulator (AGU) 5) Various field measurement technique improvement. Design features of the baseline devices, ID-Magnetic Measurement Facility and the future plans for NSLS-II ID activities are described.

Slides THOBS4 [4.171 MB]

Paper	Title	Page
TUP232	Super-Conducting Wigglers and the Effect on Injection Efficiency	1259
	M.J. Sigrist, L.O. Dallin, W.A. Wurtz CLS, Saskatoon, Saskatchewan, Canada
	The Canadian Light Source has two superconducting wigglers (SCW) operating at 2.1T and 4.3T peak fields. Injection efficiency into the storage ring is reduced by either device operating at high fields. Currently the CLS operates with a Fill and Decay mode, injecting with both wigglers at reduced field to avoid low injection efficiencies. Future implementation of a Top-up mode will require both wigglers to be operating at full field and better injection efficiencies will be required. Simulations and experiments have shown that the poor injection efficiency is related to operating a high vertical chromaticity. Much improved efficiencies are observed at when the chromaticity is lowered. As well, small improvements to the injection efficiency have been achieved through local correction of the beta-beats and tune shifts caused by the wigglers and optimisation of the injection co-ordinates of the injected beam. Measurements of the injection efficiencies at various chromaticities will be presented along with the betatron oscillations before and after correction.

TUP235	Strategy for Neutralizing the Impact of Insertion Devices on the MAX IV 3 GeV Ring	1262
	E.J. Wallén, S.C. Leemann MAX-lab, Lund, Sweden
	In order to prepare for the potentially negative influence on the beam lifetime, injection efficiency and beam size from the insertion devices (IDs) on the stored beam of the MAX IV 3 GeV storage ring strategy for neutralizing the foreseen effects of the IDs has been developed. In short the strategy involves a local correction of the betatron phase advance by adjusting the strength of the quadrupoles adjacent to the ID. There will also be a global tune correction in order to avoid drift in the working point of the storage ring during operation. Air coils with empirical feed forward tables for the excitation current in the coils will compensate for field integral errors. The lattice of the MAX IV 3 GeV storage ring appears to be robust and it tolerates the dynamic multipoles created by the expected initial set of IDs provided that the local correction of the betatron phase advance has been carried out.

TUP236	Progress of a Gradient Damping Wiggler of the ALPHA Storage Ring	1265
	C.W. Huang, D.J. Huang NTHU, Hsinchu, Taiwan S.D. Chen NCTU, Hsinchu, Taiwan M.-H. Huang, C.-S. Hwang, C.Y. Kuo, F.-Y. Lin, Y.T. Yu NSRRC, Hsinchu, Taiwan S.-Y. Lee IUCF, Bloomington, Indiana, USA
	The main purpose of a gradient damping wiggler (GDW) to be installed in the Alpha storage ring in Indiana University is to correct the momentum-compaction factor and the damping partition in the Alpha storage ring. One middle pole and two outer poles in one set of the GDW are installed on the same girder. Two sets of GDW will be installed in the two short straight sections. The dipole and gradient-field strengths of the middle (outer) pole are 0.67 T (-0.67 T) and 1.273 T m^-1 (1.273 T m^-1), respectively. One completed set of GDW is already fabricated; we shall add an end shim to improve the region of effective good field within which the middle and outer poles along the transverse x-axis (△B/B = 0.1 %) are ±50 and ±40 mm respectively. We used a trim coil on the three poles to adjust the first and second integral fields to zero. Here we discuss the integral magnetic field features along the straight trajectory and the ideal orbital trajectory with a Hall probe mapping system, and present an analysis of the magnetic field.

TUP237	Development of Accurate and Precise In-Vacuum Undulator System	1268
	A. Deyhim, J.D. Kulesza Advanced Design Consulting, Inc, Lansing, New York, USA K.I. Blomqvist MAX-lab, Lund, Sweden
	Typical in-vacuum undulators, especially long ones, have several associated engineering challenges to be accurate and precise; magnetic centerline stability, inner girder hangers, and magnet period to name a few. The following describes these issues in more detail and ADC’s methods solved these critical issues for long in vacuum undulators. ADC has designed, built and delivered Insertion Devices and Magnetic Measurement Systems to such facilities as; MAXLab (EPU, Planar-2, and Measurement System), ALBA and Australian Synchrotron Project (Wiggler), BNL (Cryo In-Vacuum), SSRF (In-Vacuum – 2, and Measurement System), PAL (In-Vacuum and Measurement System), NSRRC (In-Vacuum), and SRC (Planar and EPU). The information presented here uses data from a recent IVU we delivered to PAL. This IVU will be installed at Pohang Accelerator Laboratory (PAL) for U-SAXS (Ultra Small Angle X-ray Scattering) beamline in 2011. The IVU generates undulator radiation up to ~14 keV using higher harmonic (up to 9th) undulator radiation with 2.5 GeV PLS electron beam

TUP238	Development of an Integrated Field Measurement System (IFMS) for NSLS II	1271
	A. Deyhim, S.W. Hartman, J.D. Kulesza Advanced Design Consulting, Inc, Lansing, New York, USA
	This paper describes the mechanical design, control instrumentation and software for the Integrated Field Measurement System (IFMS) for the Magnetic Measurement Lab for the National Synchrotron Light Source II (NSLS-II) project at Brookhaven National Laboratory. Insertion devices (IDs) at NSLS II need to be accurately surveyed using an integrated field measurement system prior to insertion into the storage ring and can also be used in the tunnel for final tuning of IDs. It is a fast and precise measurement system required in determining the ID magnetic field integrals. The design is a set of long coils supported by two 3-axis X-Y-Z precision linear and two precision rotary positioning stages. The PC is the primary control unit. Eight stepping motor control cards, eight drivers, one digital I/O board, one 6U PXI card, and one integrator are installed to perform remote control and data acquisition.

TUP239	Development of a Super-Mini Undulator	1274
	A. Deyhim, J.D. Kulesza Advanced Design Consulting, Inc, Lansing, New York, USA C. Diao, H.O. Moser SSLS, Singapore, Singapore
	This paper describes development and initial results for a small prototype of a superconducting undulator with a period less than 1 cm, referred to here as a “super-mini” undulator. The development of superconducting mini-undulators started in the early 1990s with work at BNL and KIT (Germany). In 1998, KIT demonstrated the first photon production with a super-mini of 3.8 mm period length . This super-mini consisted of two coils wound bi-filarly in analogy to a solenoid. If such coils are arranged alongside each other, separated only by a small gap of the order of a couple of millimeters, a spatially alternating magnetic field is produced that makes a passing electron beam undulate and emit undulator radiation. Owing to the short period length, the photon energy is much higher than with conventional undulators at the same electron energy. Likewise, for a given photon energy, the electron energy can be much smaller entailing considerable cost savings of accelerator, building, and operations. T. Hezel, B. Krevet, H.O. Moser, J.A. Rossmanith, R. Rossmanith, and Th. Schneider, A superconductive undulator with a period length of 3.8 mm, J. Synchrotron Rad. 5(1998) pp. 448-450.

TUP240	Coil Energizing Patterns for an Electromagnetic Variably Polarizing Undulator	1277
	R.J. Dejus, M.S. Jaski, E.R. Moog ANL, Argonne, USA S. Sasaki HSRC, Higashi-Hiroshima, Japan
	Funding: The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). A new electromagnetic insertion device optimized for producing intense soft x-rays of variable polarization is under construction at the Advanced Photon Source. Most of the coil packs are powered by a main power supply; a few are powered separately so that magnetic fields at certain pole positions can be different. The undulator radiation depends sensitively on the chosen magnetic field pattern, and higher spectral harmonics may be shifted in energy. For some beamline experiments, it is important to reduce the so-called higher-order contamination to increase the signal-to-noise ratio. We present spectra and power densities calculated directly from realistic magnetic fields and discuss coil energizing patterns. Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.

TUP241	End-Field Analysis and Implementation of Correction Coils for a Short-Period NbTi Superconducting Undulator	1280
	C.L. Doose, M. Kasa, S.H. Kim ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A short period superconducting undulator (SCU) is being developed at the Advanced Photon Source (APS). The on-axis field of the prototype 1.6-cm period 42-pole SCU0 was measured with a cryogenic Hall probe system. Typical permanent magnet undulators provide end-field correction by decreasing the strength of the magnets on both ends of each jaw. In the case of the SCU0, a set of correction coils was wound on the two end grooves of each of the steel cores along with the main coils to provide the required end fields. These correction coils were connected in series and energized with one power supply to provide simple and symmetrical operation. The measured phase errors of the SCU0 were below 2 degrees rms without any local magnetic tuning of the device.

TUP242	Electron Cloud Issues for the APS Superconducting Undulator	1283
	K.C. Harkay, Y. Ivanyushenkov, R. Kustom, E.R. Moog, E. Trakhtenberg ANL, Argonne, USA L.E. Boon, A.F. Garfinkel Purdue University, West Lafayette, Indiana, USA
	Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The APS Upgrade calls for the development and commissioning of a superconducting undulator (SCU) at the Advanced Photon Source (APS), a 7-GeV electron synchrotron. Operation of an SCU at Angstromquelle Karlsruhe (ANKA), also an electron ring, suggests that electron multipacting is consistent with the observed heat load and pressure rise, but this effect is not predicted by an electron cloud generation code. At APS it was found that while the cloud code POSINST agreed fairly well with retarding field analyzer (RFA) data for a positron beam (operated 1996-98), the agreement was less satisfactory for the electron beam. The APS data suggest that the photoelectron model is not complete. Given that the heat load is a critical parameter in designing the cryosystem for the SCU and given the experience at ANKA, a study is underway to minimize the possible contribution to the heat load by the electron cloud at the APS, the photoelectrons in particular. In this talk, the results from POSINST are presented. Preliminary tracking of the photon flux using SYNRAD3D for the APS SCU chamber is presented, and possible ways to mitigate the photoelectrons are discussed.

TUP243	Development Status of a Magnetic Measurement System for the APS Superconducting Undulator	1286
	Y. Ivanyushenkov, M. Abliz, C.L. Doose, M. Kasa, E. Trakhtenberg, I. Vasserman ANL, Argonne, USA V.K. Lev, N.A. Mezentsev, V.M. Tsukanov BINP SB RAS, Novosibirsk, Russia
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Short-period superconducting undulators are being developed as part of the Advanced Photon Source (APS) upgrade program. The first test device is in fabrication. Before installation into the storage ring, the magnetic performance of the undulators will be characterized. The magnetic measurement facility routinely used for measuring and tuning conventional undulators cannot be employed for superconducting devices, so a new measurement system is being designed and built. The system is mechanically mounted on the undulator cryostat and uses a heated tube in the cold undulator bore to guide a Hall probe or measuring coils. A specially designed three-Hall sensor assembly allows measurement of the vertical and horizontal components of the magnetic field and the determination of the height of the magnetic midplane. A set of measuring coils is mounted on carbon-fiber tubes that can be translated and rotated in the undulator bore to measure the field integrals and their multipole components. The design of the measurement system and its construction status is described in this paper.

TUP244	Magnetic Simulation of an Electromagnetic Variably Polarizing Undulator *	1289
	M.S. Jaski, R.J. Dejus, E.R. Moog ANL, Argonne, USA
	Development of an all-electromagnetic variable polarizing undulator is underway at the Advanced Photon Source (APS). This device has a set of Bx poles and coils and a set of By poles and coils. The Bx coils are powered separately from the By coils. Modifying the geometry of the Bx coils or poles changes not only the Bx field but changes the By field as well and vice-versa. Magnetic modeling with OPERA 3-D software was used to optimize the coil and pole geometries. Results of the magnetic field simulation and optimization are presented in this paper. * Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract number DE-AC02-06CH11357.

TUP245	Comparison of Standard S-Glass and Ceramic Coating as Insulation in Short-Period Superconducting Undulators Based on Nb3Sn	1292
	S.H. Kim, C.L. Doose, M. Kasa, R. Kustom, E.R. Moog ANL, Argonne, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. This paper compares calculated on-axis fields for short- period superconducting undulators (SCUs) using Nb3Sn superconductor with two different insulation thicknesses, 0.02 mm and 0.05 mm. When the insulated conductor diameter remained the same, the on-axis fields using the thinner insulation were higher by about 8 – 15% for a period range of 15 – 10 mm. When the conductor diameters with the thicker insulation were made larger than the conductors with the thinner insulation, the differences were reduced to be about 6 – 12%.

TUP248	SC Undulator with the Possibility To Change Its Strength and Polarization by Feeding Current	1295
	A.A. Mikhailichenko CLASSE, Ithaca, New York, USA
	Funding: NSF We describe the design of optimized undulator with SC windings able to generate the magnetic field of opposite helicities, including an elliptic and a linear ones oriented as desired. For the undulator period 25mm and aperture 8mm, K factor could be changed from zero up to 1.5 by changing the feeding current. Polarization changed by changing the currents in additional helical windings.

THOBS1	Developments in Superconducting Insertion Devices	2077
	E.R. Moog, Y. Ivanyushenkov ANL, Argonne, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A number of superconducting wigglers are installed and in operation worldwide. Superconducting undulators, with their shorter periods and more demanding field quality requirements, present additional challenges and are still under development. Superconducting technology can produce a higher magnetic field strength on the beam axis than can a permanent-magnet-based undulator. This makes shorter period undulators feasible – they will still reach high enough field to have a reasonable photon energy tuning range. The shorter period device gives higher photon brightness at higher photon energies, opening up new opportunities for photon-hungry applications that require higher photon energies. Many light sources are interested in having a superconducting undulator; a few, including the Advanced Photon Source, have ongoing projects and are making significant progress. The status of these projects will be discussed.
	Slides THOBS1 [3.427 MB]

THOBS4	Current Status of Insertion Device Development at the NSLS-II and its Future Plans	2090
	T. Tanabe, O.V. Chubar, T.M. Corwin, D.A. Harder, P. He, C.A. Kitegi, G. Rakowsky, J. Rank, C. Rhein, C.J. Spataro BNL, Upton, Long Island, New York, USA
	Funding: This manuscript has been authored by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH1-886 with the U.S. Department of Energy. National Synchrotron Light Source-II (NSLS-II) project is currently under construction. Procurement of various insertion devices (IDs) has begun. IDs in the project baseline scope include six 3.5m long damping wigglers (DWs) with 100mm period, two 2.0m Elliptically Polarizing Undulator (EPU) with 49mm period, two 3.0m-20mm period IVUs and one 1.5m-21mm IVU. Recently a special device for inelastic X-ray scattering beamline has been added to the collection of baseline devices. This is a special wide pole IVU with 22mm period for a long straight section. Three pole wigglers with 28mm gap and peak field over 1T will be utilized for NSLS bending magnet users. Examples of R&D work for future devices are: 1) Development of in-vacuum magnetic measurement system (IVMMS), 2) Use of new type of magnet such as PrFeB for improved performance on cryo-permanent magnet undulator (CPMU), 3) Development of closed loop He gas refrigerator with a linear motor actuator, 4) Adaptive gap undulator (AGU) 5) Various field measurement technique improvement. Design features of the baseline devices, ID-Magnetic Measurement Facility and the future plans for NSLS-II ID activities are described.
	Slides THOBS4 [4.171 MB]