IPAC2011 - List of Keywords (polarization)

Paper	Title	Other Keywords	Page
TUPC006	Production of Highly Polarized Positron Beams*	undulator, positron, photon, target	997
	A. Ushakov, O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick University of Hamburg, Hamburg, Germany A.F. Hartin DESY, Hamburg, Germany S. Riemann, A. Schälicke, F. Staufenbiel DESY Zeuthen, Zeuthen, Germany
	Funding: This work is supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Management", contract number 05H10GUE Using of polarized electron and positron beams significantly increases the physics potential of future linear colliders. The generation of an intense and highly polarized positron beam is a challenge. The undulator-based positron source located at the end of electron linac is the baseline source for the International Linear Collider. In case of a 250 GeV drive beam energy, an helical undulator with K = 0.92, an undulator period of 11.5 mm and a titanium alloy target of 0.4 radiation length thickness, the average polarization of the generated positrons is relatively low (about 22 percent). In this contribution, the possibilities of increasing the positron polarization have been considered by adjusting the undulator field and selecting those photons and positrons that yield a highly polarized beam. The detailed simulations have been performed with our developed Geant4-based application PPS-Sim. http://pps-sim.desy.de

TUPC072	Accurate Electron Beam Size Measurement at the Metrology Light Source	electron, photon, radiation, storage-ring	1165
	R. Klein, G. Brandt, R. Thornagel PTB, Berlin, Germany J. Feikes, M. Ries, G. Wüstefeld HZB, Berlin, Germany
	For the operation of the Metrology Light Source (MLS), the dedicated electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB), as the national primary radiation source standard from the near infrared to the vacuum ultraviolet spectral region, all storage ring parameters which are relevant for the calculation of the radiant intensity by the Schwinger equation have to be known absolutely with small uncertainties. For the measurement of the effective vertical electron beam size a Bragg polarimeter, operating at a photon energy of 1103 eV, has been designed and put into operation. This system also serves as a detection system for the image of the electron beam through a set of narrow slits. The results obtained with the new device are compared to those measured by an optical beam imaging system. R. Klein et al., Phys. Rev. ST-AB 11, 110701 (2008). ** C. Koschitzki et al., Proc. IPAC10, 894-896 (2010).

TUPC074	A New Counting Silicon Strip Detector System for Precise Compton Polarimetry	electron, photon, laser, scattering	1171
	R. Zimmermann, W. Hillert, J.C. Wittschen ELSA, Bonn, Germany
	Funding: Supported by the German Research Foundation within the SFB/TR16 A Compton polarimeter is currently being installed at the Electron Stretcher Facility ELSA to monitor the degree of polarization of the stored electron beam. For this purpose, circularly polarized light that is emitted by a laser and backscattered off the beam has to be detected. Above all, as a result of ELSA's beam energies, it is necessary to measure the shift of the center of the photon spatial distribution which is obtained when the polarization of the laser is switched from left-hand to right-hand circular polarization with an accuracy of a few microns. In order to meet the required specifications, a new counting silicon strip detector system has been developed in cooperation with the SiLab/ATLAS group of the Physics Institute of the University of Bonn. In this contribution, the design of the system will be presented and first results will be shown.

TUPC169	Single-shot Electro-optic Sampling of Coherent Transition Radiation at the A0 Photoinjector	laser, radiation, diagnostics, electron	1431
	T.J. Maxwell, P. Piot Northern Illinois University, DeKalb, Illinois, USA J. Ruan, R.M. Thurman-Keup Fermilab, Batavia, USA
	Funding: Work supported by Fermi Research Alliance, LLC under U.S. Dept. of Energy Contract No. DE-AC02-07CH11359, and Northern Illinois Univ. under US Dept. of Defense DURIP program Contract N00014-08-1-10⁶⁴. Future collider applications and present high-gradient laser plasma wakefield accelerators operating with picosecond bunch durations place a higher demand on the time resolution of bunch distribution diagnostics. This demand has led to significant advancements in the field of electro-optic sampling over the past ten years. These methods allow the probing of diagnostic light such as coherent transition radiation () or the bunch wakefields () with sub-picosecond time resolution. Potential applications in shot-to-shot, non-interceptive diagnostics continue to be pursued for live beam monitoring of collider and pump-probe experiments. Related to our developing work with electro-optic imaging, we present results on single-shot electro-optic sampling of the coherent transition radiation from bunches generated at the A0 photoinjector. J. van Tilborg et al., Phys. Rev. Lett. 96, 014801 (2006). ** M. J. Fitch et al., Phys. Rev. Lett. 87 034801 (2001).

TUPZ035	RHIC Polarized Proton Status and Operation Highlights	resonance, feedback, emittance, controls	1888
	H. Huang, L. A. Ahrens, I.G. Alekseev, E.C. Aschenauer, G. Atoian, M. Bai, A. Bazilevsky, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, A. Dion, K.A. Drees, W. Fischer, J.W. Glenn, X. Gu, L.T. Hoff, C. Liu, Y. Luo, W.W. MacKay, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, M.G. Minty, C. Montag, J. Morris, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, D. Smirnov, S. Tepikian, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, S.Y. Zhang BNL, Upton, Long Island, New York, USA D. Svirida ITEP, Moscow, Russia
	RHIC operation as the polarized proton collider presents unique challenges since both luminosity and spin polarization are important. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system has been installed to improve longitudinal match at injection and to increase luminosity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control has also been improved this year. AGS polarization transfer efficiency is improved by a horizontal tune jump system. To preserve polarization on the ramp, a new working point was chosen with the vertical tune near a third order resonance. The orbit and tune control are essential for polarization preservation. To calibrate the polarization level at 250 GeV, polarized protons were accelerated up to 250GeV and decelerated back to 100GeV. The tune, orbit and chromaticity feedback is essential for this operation. The new record of luminosity was achieved with higher polarization at 250 GeV in this run. The overview of the changes and operation results are presented in this paper.

WEOAB01	Highly Polarized and High Quantum Efficiency Electron Source Using Transmission-type Photocathode	electron, laser, gun, brightness	1950
	N. Yamamoto, F. Ichihashi, A. Mano, T. Nakanishi, Y. Takeda, T. Ujihara Nagoya University, Nagoya, Japan X.G. Jin Institute for Advanced Research, Nagoya, Japan
	The GaAs-type semiconductor photocathodes (PCs) with a negative electron affinity surface have been used as a polarized electron source and are expected as electron sources for next generation accelerators, such as Linear Colliders and Energy Recovery Linacs. Recently, we have developed transmission-type photocathodes (T-PCs).　By using T-PCs, polarized electron beam is extracted from the back-side of laser irradiation-side.　This scheme offers great merits in designing electron guns, such as short focusing of the laser light for a high brilliance electron beam and a simple geometrical structure avoiding an interference problem between the laser and the electron beam. The layer structure of the MOVPE-grown superlattice photocathode and the performance of 90% polarization, a super high brilliance, and a high quantum efficiency will be reported.
	Slides WEOAB01 [6.007 MB]

WEYB01	Diagnostics for Ultra-low Emittance Beams	laser, radiation, emittance, optics	1959
	J.W. Flanagan KEK, Ibaraki, Japan
	The achievement in recent years of beams with vertical emittance of a few pico-meters in a number of electron storage rings has presented challenges for diagnostics capable of beam size measurements in this regime. A number of different approaches have been developed for various machines (e.g. laser wire; interferometer; Shintake monitor; coded aperture; compound refractive lens). This presentation will review and compare the different methods, and discuss their strengths, weaknesses, ultimate limitations, and the situations where they might be appropriate; and consider possible future directions.
	Slides WEYB01 [2.553 MB]

WEIB01	Chasing Femtoseconds – How Accelerators Can Benefit from Economies of Scale in Other Industries	laser, optics, scattering, controls	1973
	M. Vidmar, J. Tratnik University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia P.L. Lemut COBIK, Solkan, Slovenia
	Building accelerators we frequently push the limits of what is possible in terms of performance. When trying to solve a very challenging engineering problem, we normally resort to specialization; we narrow our focus. This talk suggests a possible alternative path. Huge benefits and great results can be achieved by combining creative ideas and approaches with ideas and solutions borrowed from the economies of scale like telecommunications. The aim of the talk is to show possibilities for combining ideas, technologies and components from different industries into innovative products.
	Slides WEIB01 [0.799 MB]

WEPC052	Spinor Based Calculation of Depolarizing Effects in Circular Lepton Accelerators	synchrotron, resonance, lepton, photon	2130
	O. Boldt, A. Dieckmann, F. Frommberger, W. Hillert ELSA, Bonn, Germany
	Funding: BMBF The emission of synchrotron radiation strongly influences the beam dynamics in case of ultra relativistic leptons. When storing or accelerating leptons in circular accelerators, the acting magnetic field shows an oscillating behavior in the rest frame of the leptons. Its properties can be determined by a spectral analysis. The stochastic emission of synchrotron light leads to a line broadening within the magnetic field spectrum. This spectrum can be used to simulate depolarizing effects in circular accelerators. Our contribution will present a tracking based calculation of the mentioned spectrum and a spinor-based determination of the resulting population of the spin-up state. These calculations base on the lattice of the electron stretcher accelerator (ELSA, Bonn) and are confirmed by measurements of the polarization.

WEPC053	Crossing of Depolarizing Resonances in Circular Electron Accelerators	resonance, electron, closed-orbit, quadrupole	2133
	W. Hillert, A. Balling, O. Boldt, A. Dieckmann, F. Frommberger ELSA, Bonn, Germany
	Funding: Supported by the German Research Foundation (DFG) through SFB/TR 16 In flat electron storage rings, only the vertical component of the beam polarization is preserved. During acceleration, the crossing of several depolarizing resonances may cause severe beam depolarization. Even in case of fast ramping speeds of up to 6 GeV/sec, first order effects like imperfection and intrinsic resonances have to be compensated by dedicated measures. At the accelerator facility ELSA, schemes like fast tune jumping and harmonic orbit correction are successfully applied on the fast energy ramp up to 3.2 GeV. Characteristics of the setup as well as the optimization efforts to improve the resonance compensation will be reported in detail.

WEPC137	Undulator Radiation Simulation by QUINDI	undulator, radiation, electron, simulation	2316
	D. Schiller, E. Hemsing, J.B. Rosenzweig UCLA, Los Angeles, California, USA
	QUINDI, a code developed to simulate coherent emission from bending systems, has been upgraded to include undulators as a beamline element. This approach allows us to better model the radiation produced by a relativistic electron bunch propagating through such a device.

THPC006	Experiments to Measure Electron Beam Energy using Spin Depolarization Method on SOLEIL Storage Ring	storage-ring, electron, beam-losses, synchrotron	2915
	J.F. Zhang, L. Cassinari, M. Labat, A. Nadji, L.S. Nadolski, D. Pédeau SOLEIL, Gif-sur-Yvette, France
	The electron beam energy on SOLEIL storage ring was successfully measured using spin depolarization method after several attempts over the past few years. The experimental results demonstrate that the effective polarization was 91.3%±3% and polarization time was 17±2.3 minutes as expected from the simulation using SLIM code. The beam was depolarized using an AC shaker and the depolarization was monitored using DCCT and beam loss monitors. The beam energy was measured with accuracy up to a few 10^-5.

THPC164	Phase Shifters for the FERMI@Elettra Undulators	undulator, electron, FEL, radiation	3278
	B. Diviacco, R. Bracco, D. Millo, M.M. Musardo ELETTRA, Basovizza, Italy
	The variable gap undulator system in operation at the FERMI@Elettra Free Electron Laser facility requires adjustable phase matching devices between consecutive radiator segments in order to maintain optimal lasing conditions while changing the radiation properties. A permanent magnet phase shifter has been designed to achieve the required electron beam delay in a compact structure that could be installed in close proximity to the undulators. In this paper we present the design of the phasing units and the results of the magnetic measurements performed on the five devices installed so far. We also describe the method used to properly set their field strength for any given electron energy, radiation wavelength and polarization.

THPC184	Progress of the Coherent Soft X Ray Straight Section at NSLS-II	undulator, electron, photon, insertion	3329
	C.A. Kitegi, P. Cappadoro, O.V. Chubar, T.M. Corwin, D.A. Harder, P. He, Y. Li, C. Meyer, G. Rakowsky, J. Rank, C. Rhein, C.J. Spataro, T. Tanabe BNL, Upton, Long Island, New York, USA
	The National Synchrotron Light Source II (NSLS-II) is the new light source under construction at Brookhaven National Laboratory (BNL). The Coherent Soft X rays beam line (CSX) is one of the six beamlines included in the baseline project. Following the request of CSX scientists for a source providing adjustable polarized radiation from 160 eV to 1.7 keV, two Advanced Planar Polarized Light Emitter II (APPLE-II)-type undulators will be installed in a 6.6 m long straight section. Each device is 2 m long, the period is 49.2 mm and the minimum gap is 11.5 mm. The different operation modes of the beamline and the layout of the straight section are reviewed here.

THPS101	Present and Perspectives of the Sparc THz Source	radiation, electron, linac, single-bunch	3669
	E. Chiadroni, M. Bellaveglia, M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, G. Gatti, E. Pace, C. Vaccarezza INFN/LNF, Frascati (Roma), Italy P. Calvani, S. Lupi, A. Nucara Università di Roma I La Sapienza, Roma, Italy L. Catani, B. Marchetti INFN-Roma II, Roma, Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy O. Limaj University of Rome La Sapienza, Rome, Italy A. Mostacci, L. Palumbo Rome University La Sapienza, Roma, Italy C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy
	The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). Its measured peak power is of the order of 10⁸ W, very competitive with respect to other present sources. The present status of the source is presented and future perspectives are presented.

THPZ001	Spin Dynamic Tool Developments and Study Regarding the Super-B Project	closed-orbit, simulation, lattice, collider	3681
	N. Monseu, J.-M. De Conto LPSC, Grenoble Cedex, France F. Méot BNL, Upton, Long Island, New York, USA U. Wienands SLAC, Menlo Park, California, USA
	The study of polarization is essential for e+/e^- colliders like the SuperB machine. The ZGOUBI integrator is a good and universal tool for particle tracking as well as spin tracking, and takes into account all machine realistic aspects, like real fields, non-linearities, fringing fields or misalignments. We present ZGOUBI implementation and the methods carried out to estimate invariant spin field and beam polarization evolution on some simple models (for validation) and on SuperB, and we investigate for some specific polarization behavior.

Paper

Title

Other Keywords

Page

TUPC006

Production of Highly Polarized Positron Beams*

undulator, positron, photon, target

997

A. Ushakov, O.S. Adeyemi, V.S. Kovalenko, L.I. Malysheva, G.A. Moortgat-Pick
University of Hamburg, Hamburg, Germany
A.F. Hartin
DESY, Hamburg, Germany
S. Riemann, A. Schälicke, F. Staufenbiel
DESY Zeuthen, Zeuthen, Germany

Funding: This work is supported by the German Federal Ministry of Education and Research, Joint Research Project R&D Accelerator "Spin Management", contract number 05H10GUE
Using of polarized electron and positron beams significantly increases the physics potential of future linear colliders. The generation of an intense and highly polarized positron beam is a challenge. The undulator-based positron source located at the end of electron linac is the baseline source for the International Linear Collider. In case of a 250 GeV drive beam energy, an helical undulator with K = 0.92, an undulator period of 11.5 mm and a titanium alloy target of 0.4 radiation length thickness, the average polarization of the generated positrons is relatively low (about 22 percent). In this contribution, the possibilities of increasing the positron polarization have been considered by adjusting the undulator field and selecting those photons and positrons that yield a highly polarized beam. The detailed simulations have been performed with our developed Geant4-based application PPS-Sim*.
* http://pps-sim.desy.de

TUPC072

Accurate Electron Beam Size Measurement at the Metrology Light Source

electron, photon, radiation, storage-ring

1165

R. Klein, G. Brandt, R. Thornagel
PTB, Berlin, Germany
J. Feikes, M. Ries, G. Wüstefeld
HZB, Berlin, Germany

For the operation of the Metrology Light Source (MLS)*, the dedicated electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB), as the national primary radiation source standard from the near infrared to the vacuum ultraviolet spectral region, all storage ring parameters which are relevant for the calculation of the radiant intensity by the Schwinger equation have to be known absolutely with small uncertainties. For the measurement of the effective vertical electron beam size a Bragg polarimeter, operating at a photon energy of 1103 eV, has been designed and put into operation. This system also serves as a detection system for the image of the electron beam through a set of narrow slits. The results obtained with the new device are compared to those measured by an optical beam imaging system**.
* R. Klein et al., Phys. Rev. ST-AB 11, 110701 (2008).
** C. Koschitzki et al., Proc. IPAC10, 894-896 (2010).

TUPC074

A New Counting Silicon Strip Detector System for Precise Compton Polarimetry

electron, photon, laser, scattering

1171

R. Zimmermann, W. Hillert, J.C. Wittschen
ELSA, Bonn, Germany

Funding: Supported by the German Research Foundation within the SFB/TR16
A Compton polarimeter is currently being installed at the Electron Stretcher Facility ELSA to monitor the degree of polarization of the stored electron beam. For this purpose, circularly polarized light that is emitted by a laser and backscattered off the beam has to be detected. Above all, as a result of ELSA's beam energies, it is necessary to measure the shift of the center of the photon spatial distribution which is obtained when the polarization of the laser is switched from left-hand to right-hand circular polarization with an accuracy of a few microns. In order to meet the required specifications, a new counting silicon strip detector system has been developed in cooperation with the SiLab/ATLAS group of the Physics Institute of the University of Bonn. In this contribution, the design of the system will be presented and first results will be shown.

TUPC169

Single-shot Electro-optic Sampling of Coherent Transition Radiation at the A0 Photoinjector

laser, radiation, diagnostics, electron

1431

T.J. Maxwell, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J. Ruan, R.M. Thurman-Keup
Fermilab, Batavia, USA

Funding: Work supported by Fermi Research Alliance, LLC under U.S. Dept. of Energy Contract No. DE-AC02-07CH11359, and Northern Illinois Univ. under US Dept. of Defense DURIP program Contract N00014-08-1-10⁶⁴.
Future collider applications and present high-gradient laser plasma wakefield accelerators operating with picosecond bunch durations place a higher demand on the time resolution of bunch distribution diagnostics. This demand has led to significant advancements in the field of electro-optic sampling over the past ten years. These methods allow the probing of diagnostic light such as coherent transition radiation (*) or the bunch wakefields (**) with sub-picosecond time resolution. Potential applications in shot-to-shot, non-interceptive diagnostics continue to be pursued for live beam monitoring of collider and pump-probe experiments. Related to our developing work with electro-optic imaging, we present results on single-shot electro-optic sampling of the coherent transition radiation from bunches generated at the A0 photoinjector.
* J. van Tilborg et al., Phys. Rev. Lett. 96, 014801 (2006).
** M. J. Fitch et al., Phys. Rev. Lett. 87 034801 (2001).

TUPZ035

RHIC Polarized Proton Status and Operation Highlights

resonance, feedback, emittance, controls

1888

H. Huang, L. A. Ahrens, I.G. Alekseev, E.C. Aschenauer, G. Atoian, M. Bai, A. Bazilevsky, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, A. Dion, K.A. Drees, W. Fischer, J.W. Glenn, X. Gu, L.T. Hoff, C. Liu, Y. Luo, W.W. MacKay, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, M.G. Minty, C. Montag, J. Morris, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, D. Smirnov, S. Tepikian, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, S.Y. Zhang
BNL, Upton, Long Island, New York, USA
D. Svirida
ITEP, Moscow, Russia

RHIC operation as the polarized proton collider presents unique challenges since both luminosity and spin polarization are important. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system has been installed to improve longitudinal match at injection and to increase luminosity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control has also been improved this year. AGS polarization transfer efficiency is improved by a horizontal tune jump system. To preserve polarization on the ramp, a new working point was chosen with the vertical tune near a third order resonance. The orbit and tune control are essential for polarization preservation. To calibrate the polarization level at 250 GeV, polarized protons were accelerated up to 250GeV and decelerated back to 100GeV. The tune, orbit and chromaticity feedback is essential for this operation. The new record of luminosity was achieved with higher polarization at 250 GeV in this run. The overview of the changes and operation results are presented in this paper.

WEOAB01

Highly Polarized and High Quantum Efficiency Electron Source Using Transmission-type Photocathode

electron, laser, gun, brightness

1950

N. Yamamoto, F. Ichihashi, A. Mano, T. Nakanishi, Y. Takeda, T. Ujihara
Nagoya University, Nagoya, Japan
X.G. Jin
Institute for Advanced Research, Nagoya, Japan

The GaAs-type semiconductor photocathodes (PCs) with a negative electron affinity surface have been used as a polarized electron source and are expected as electron sources for next generation accelerators, such as Linear Colliders and Energy Recovery Linacs. Recently, we have developed transmission-type photocathodes (T-PCs).　By using T-PCs, polarized electron beam is extracted from the back-side of laser irradiation-side.　This scheme offers great merits in designing electron guns, such as short focusing of the laser light for a high brilliance electron beam and a simple geometrical structure avoiding an interference problem between the laser and the electron beam. The layer structure of the MOVPE-grown superlattice photocathode and the performance of 90% polarization, a super high brilliance, and a high quantum efficiency will be reported.

Slides WEOAB01 [6.007 MB]

WEYB01

Diagnostics for Ultra-low Emittance Beams

laser, radiation, emittance, optics

1959

J.W. Flanagan
KEK, Ibaraki, Japan

The achievement in recent years of beams with vertical emittance of a few pico-meters in a number of electron storage rings has presented challenges for diagnostics capable of beam size measurements in this regime. A number of different approaches have been developed for various machines (e.g. laser wire; interferometer; Shintake monitor; coded aperture; compound refractive lens). This presentation will review and compare the different methods, and discuss their strengths, weaknesses, ultimate limitations, and the situations where they might be appropriate; and consider possible future directions.

Slides WEYB01 [2.553 MB]

WEIB01

Chasing Femtoseconds – How Accelerators Can Benefit from Economies of Scale in Other Industries

laser, optics, scattering, controls

1973

M. Vidmar, J. Tratnik
University of Ljubljana, Faculty of Electrical Engineering, Ljubljana, Slovenia
P.L. Lemut
COBIK, Solkan, Slovenia

Building accelerators we frequently push the limits of what is possible in terms of performance. When trying to solve a very challenging engineering problem, we normally resort to specialization; we narrow our focus. This talk suggests a possible alternative path. Huge benefits and great results can be achieved by combining creative ideas and approaches with ideas and solutions borrowed from the economies of scale like telecommunications. The aim of the talk is to show possibilities for combining ideas, technologies and components from different industries into innovative products.

Slides WEIB01 [0.799 MB]

WEPC052

Spinor Based Calculation of Depolarizing Effects in Circular Lepton Accelerators

synchrotron, resonance, lepton, photon

2130

O. Boldt, A. Dieckmann, F. Frommberger, W. Hillert
ELSA, Bonn, Germany

Funding: BMBF
The emission of synchrotron radiation strongly influences the beam dynamics in case of ultra relativistic leptons. When storing or accelerating leptons in circular accelerators, the acting magnetic field shows an oscillating behavior in the rest frame of the leptons. Its properties can be determined by a spectral analysis. The stochastic emission of synchrotron light leads to a line broadening within the magnetic field spectrum. This spectrum can be used to simulate depolarizing effects in circular accelerators. Our contribution will present a tracking based calculation of the mentioned spectrum and a spinor-based determination of the resulting population of the spin-up state. These calculations base on the lattice of the electron stretcher accelerator (ELSA, Bonn) and are confirmed by measurements of the polarization.

WEPC053

Crossing of Depolarizing Resonances in Circular Electron Accelerators

resonance, electron, closed-orbit, quadrupole

2133

W. Hillert, A. Balling, O. Boldt, A. Dieckmann, F. Frommberger
ELSA, Bonn, Germany

Funding: Supported by the German Research Foundation (DFG) through SFB/TR 16
In flat electron storage rings, only the vertical component of the beam polarization is preserved. During acceleration, the crossing of several depolarizing resonances may cause severe beam depolarization. Even in case of fast ramping speeds of up to 6 GeV/sec, first order effects like imperfection and intrinsic resonances have to be compensated by dedicated measures. At the accelerator facility ELSA, schemes like fast tune jumping and harmonic orbit correction are successfully applied on the fast energy ramp up to 3.2 GeV. Characteristics of the setup as well as the optimization efforts to improve the resonance compensation will be reported in detail.

WEPC137

Undulator Radiation Simulation by QUINDI

undulator, radiation, electron, simulation

2316

D. Schiller, E. Hemsing, J.B. Rosenzweig
UCLA, Los Angeles, California, USA

QUINDI, a code developed to simulate coherent emission from bending systems, has been upgraded to include undulators as a beamline element. This approach allows us to better model the radiation produced by a relativistic electron bunch propagating through such a device.

THPC006

Experiments to Measure Electron Beam Energy using Spin Depolarization Method on SOLEIL Storage Ring

storage-ring, electron, beam-losses, synchrotron

2915

J.F. Zhang, L. Cassinari, M. Labat, A. Nadji, L.S. Nadolski, D. Pédeau
SOLEIL, Gif-sur-Yvette, France

The electron beam energy on SOLEIL storage ring was successfully measured using spin depolarization method after several attempts over the past few years. The experimental results demonstrate that the effective polarization was 91.3%±3% and polarization time was 17±2.3 minutes as expected from the simulation using SLIM code. The beam was depolarized using an AC shaker and the depolarization was monitored using DCCT and beam loss monitors. The beam energy was measured with accuracy up to a few 10^-5.

THPC164

Phase Shifters for the FERMI@Elettra Undulators

undulator, electron, FEL, radiation

3278

B. Diviacco, R. Bracco, D. Millo, M.M. Musardo
ELETTRA, Basovizza, Italy

The variable gap undulator system in operation at the FERMI@Elettra Free Electron Laser facility requires adjustable phase matching devices between consecutive radiator segments in order to maintain optimal lasing conditions while changing the radiation properties. A permanent magnet phase shifter has been designed to achieve the required electron beam delay in a compact structure that could be installed in close proximity to the undulators. In this paper we present the design of the phasing units and the results of the magnetic measurements performed on the five devices installed so far. We also describe the method used to properly set their field strength for any given electron energy, radiation wavelength and polarization.

THPC184

Progress of the Coherent Soft X Ray Straight Section at NSLS-II

undulator, electron, photon, insertion

3329

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

The National Synchrotron Light Source II (NSLS-II) is the new light source under construction at Brookhaven National Laboratory (BNL). The Coherent Soft X rays beam line (CSX) is one of the six beamlines included in the baseline project. Following the request of CSX scientists for a source providing adjustable polarized radiation from 160 eV to 1.7 keV, two Advanced Planar Polarized Light Emitter II (APPLE-II)-type undulators will be installed in a 6.6 m long straight section. Each device is 2 m long, the period is 49.2 mm and the minimum gap is 11.5 mm. The different operation modes of the beamline and the layout of the straight section are reviewed here.

THPS101

Present and Perspectives of the Sparc THz Source

radiation, electron, linac, single-bunch

3669

E. Chiadroni, M. Bellaveglia, M. Boscolo, M. Castellano, G. Di Pirro, M. Ferrario, G. Gatti, E. Pace, C. Vaccarezza
INFN/LNF, Frascati (Roma), Italy
P. Calvani, S. Lupi, A. Nucara
Università di Roma I La Sapienza, Roma, Italy
L. Catani, B. Marchetti
INFN-Roma II, Roma, Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy
O. Limaj
University of Rome La Sapienza, Rome, Italy
A. Mostacci, L. Palumbo
Rome University La Sapienza, Roma, Italy
C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

The development of radiation sources in the THz spectral region has become more and more interesting because of the peculiar characteristics of this radiation: it is non ionizing, it penetrates dielectrics, it is highly absorbed by polar liquids, highly reflected by metals and reveals specific "fingerprint" absorption spectra arising from fundamentals physical processes. The THz source at SPARC is an accelerator based source for research investigations (e.g. material science, biology fields). Its measured peak power is of the order of 10⁸ W, very competitive with respect to other present sources. The present status of the source is presented and future perspectives are presented.

THPZ001

Spin Dynamic Tool Developments and Study Regarding the Super-B Project

closed-orbit, simulation, lattice, collider

3681

N. Monseu, J.-M. De Conto
LPSC, Grenoble Cedex, France
F. Méot
BNL, Upton, Long Island, New York, USA
U. Wienands
SLAC, Menlo Park, California, USA

The study of polarization is essential for e+/e^- colliders like the SuperB machine. The ZGOUBI integrator is a good and universal tool for particle tracking as well as spin tracking, and takes into account all machine realistic aspects, like real fields, non-linearities, fringing fields or misalignments. We present ZGOUBI implementation and the methods carried out to estimate invariant spin field and beam polarization evolution on some simple models (for validation) and on SuperB, and we investigate for some specific polarization behavior.