DIPAC2011 - List of Keywords (scattering)

Paper	Title	Other Keywords	Page
MOOB01	An Aperture Backscatter X-ray Beam Position Monitor at Diamond	photon, vacuum, polarization, undulator	6
	C. Bloomer, G. Rehm, C.A. Thomas Diamond, Oxfordshire, United Kingdom
	This paper presents the design and first results of a new XBPM developed at Diamond that images the backscatter from an aperture in the Front End to measure the beam centre of mass. This is of particular interest for monitoring the emission from elliptically polarizing undulators where the profile of the beam varies strongly with change of beam polarization. Traditional four-blade Front End XBPMs struggle to resolve a beam centre of mass for EPUs because of this. We have developed an XBPM that observes the backscattered photons from a copper aperture through a pinhole. This solution is capable of operating with the full white beam, and has been designed to fit into the same physical space as the standard front end XBPMs in use at Diamond. This offers the potential to easily replace traditional XBPMs where beneficial and required.
	Slides MOOB01 [7.211 MB]

MOPD48	Optical Electron Beam Diagnostics for Relativistic Electron Cooling Devices	electron, laser, photon, diagnostics	158
	T. Weilbach HIM, Mainz, Germany K. Aulenbacher IKP, Mainz, Germany J. Dietrich FZJ, Jülich, Germany
	New magnetized high energy coolers like the one proposed for the High Energy Storage Ring (HESR) at the Facility for Antiproton and Ion Research (FAIR) have specific demands on the diagnostic of the electron beam. Due to high voltage breakdowns they only allow a very small beam loss so non-invasive beam diagnostic methods are necessary. For beam profile measurement a system based on beam induced fluorescence (BIF) was designed and is under installation at the 100 keV polarized test setup at the Mainzer Mikrotron (MAMI) at the moment. For the diagnostic of other observables of the cooling beam, like the electron beam energy or the electron temperature, a Thomson scattering experiment is planned at the same setup. The planned experiments for the beam profile measurement are presented and the challenges of the Thomson scattering method are discussed.

TUPD53	A Low-Power Laser Wire with Fiber Optic Distribution	laser, diagnostics, electron, pick-up	425
	R.B. Wilcox, J.M. Byrd, M.S. Zolotorev LBNL, Berkeley, California, USA V.E. Scarpine Fermilab, Batavia, USA
	Funding: This work was supported by the US Department of Energy under contract DE-AC02-05CH11231. Laser-based position diagnostics for hydrogen ion (H⁻) beams typically use high power optical pulses that must be transported via free space to the diagnostic point. It is difficult to maintain stable alignment through such systems, especially when multiple channels are required. We describe a method for distributing low power, amplitude modulated pulse trains via fiber optic, and detecting interaction with the H⁻ beam by synchronous detection of the stripped electrons. Trains of 10 ps, 10⁶⁴ nm pulses at 400 MHz repetition rate are modulated by a 1 MHz signal that is the reference for a lockin amplifier. The average beam power is below one Watt. Synchronous detection at RF frequencies allows for efficient noise rejection when using optical powers below the nonlinear (Raman scattering) threshold of an optical fiber. The laser is synchronized with the bunch repetition rate, so the diagnostic can be used for bunch length measurements as well. We present results of tests of the optical system with 10⁰ m, single-mode fiber and realistic detected signal levels, demonstrating detection of the modulation signal with high signal-to-noise ratio and low nonlinearity.

WEOB01	Scintillating Screen Applications in Beam Diagnostics	electron, ion, diagnostics, photon	553
	B. Walasek-Höhne GSI, Darmstadt, Germany G. Kube DESY, Hamburg, Germany
	Scintillation screens are widely used for transverse beam profile diagnostics at particle accelerators. The monitor principle relies on the fact that a charged particle crossing the screen material will deposit a part of its energy which is converted to visible light. The resulting light spot is a direct image of the two-dimensional beam distribution and can be measured with standard optical techniques. Scintillating screen monitors were mainly deployed in hadron and low energy electron machines where the intensity of optical transition radiation (OTR) is rather low. The experience from modern linac based light sources showed that OTR diagnostics might fail even for high energetic electron beams, thus making the use of scintillators again very attractive. This contribution summarizes results and trends from "Scintillating Screen Applications in Beam Diagnostics" workshop recently held in Darmstadt. In the first part an introduction to the scintillation mechanism will be given, including demands and limitations as e.g. the dynamic range and saturation. Thereafter a brief overview on actual screen monitor applications at electron and hadron accelerators will be presented.
	Slides WEOB01 [14.721 MB]

Paper

Title

Other Keywords

Page

MOOB01

An Aperture Backscatter X-ray Beam Position Monitor at Diamond

photon, vacuum, polarization, undulator

6

C. Bloomer, G. Rehm, C.A. Thomas
Diamond, Oxfordshire, United Kingdom

This paper presents the design and first results of a new XBPM developed at Diamond that images the backscatter from an aperture in the Front End to measure the beam centre of mass. This is of particular interest for monitoring the emission from elliptically polarizing undulators where the profile of the beam varies strongly with change of beam polarization. Traditional four-blade Front End XBPMs struggle to resolve a beam centre of mass for EPUs because of this. We have developed an XBPM that observes the backscattered photons from a copper aperture through a pinhole. This solution is capable of operating with the full white beam, and has been designed to fit into the same physical space as the standard front end XBPMs in use at Diamond. This offers the potential to easily replace traditional XBPMs where beneficial and required.

Slides MOOB01 [7.211 MB]

MOPD48

Optical Electron Beam Diagnostics for Relativistic Electron Cooling Devices

electron, laser, photon, diagnostics

158

T. Weilbach
HIM, Mainz, Germany
K. Aulenbacher
IKP, Mainz, Germany
J. Dietrich
FZJ, Jülich, Germany

New magnetized high energy coolers like the one proposed for the High Energy Storage Ring (HESR) at the Facility for Antiproton and Ion Research (FAIR) have specific demands on the diagnostic of the electron beam. Due to high voltage breakdowns they only allow a very small beam loss so non-invasive beam diagnostic methods are necessary. For beam profile measurement a system based on beam induced fluorescence (BIF) was designed and is under installation at the 100 keV polarized test setup at the Mainzer Mikrotron (MAMI) at the moment. For the diagnostic of other observables of the cooling beam, like the electron beam energy or the electron temperature, a Thomson scattering experiment is planned at the same setup. The planned experiments for the beam profile measurement are presented and the challenges of the Thomson scattering method are discussed.

TUPD53

A Low-Power Laser Wire with Fiber Optic Distribution

laser, diagnostics, electron, pick-up

425

R.B. Wilcox, J.M. Byrd, M.S. Zolotorev
LBNL, Berkeley, California, USA
V.E. Scarpine
Fermilab, Batavia, USA

Funding: This work was supported by the US Department of Energy under contract DE-AC02-05CH11231.
Laser-based position diagnostics for hydrogen ion (H⁻) beams typically use high power optical pulses that must be transported via free space to the diagnostic point. It is difficult to maintain stable alignment through such systems, especially when multiple channels are required. We describe a method for distributing low power, amplitude modulated pulse trains via fiber optic, and detecting interaction with the H⁻ beam by synchronous detection of the stripped electrons. Trains of 10 ps, 10⁶⁴ nm pulses at 400 MHz repetition rate are modulated by a 1 MHz signal that is the reference for a lockin amplifier. The average beam power is below one Watt. Synchronous detection at RF frequencies allows for efficient noise rejection when using optical powers below the nonlinear (Raman scattering) threshold of an optical fiber. The laser is synchronized with the bunch repetition rate, so the diagnostic can be used for bunch length measurements as well. We present results of tests of the optical system with 10⁰ m, single-mode fiber and realistic detected signal levels, demonstrating detection of the modulation signal with high signal-to-noise ratio and low nonlinearity.

WEOB01

Scintillating Screen Applications in Beam Diagnostics

electron, ion, diagnostics, photon

553

B. Walasek-Höhne
GSI, Darmstadt, Germany
G. Kube
DESY, Hamburg, Germany

Scintillation screens are widely used for transverse beam profile diagnostics at particle accelerators. The monitor principle relies on the fact that a charged particle crossing the screen material will deposit a part of its energy which is converted to visible light. The resulting light spot is a direct image of the two-dimensional beam distribution and can be measured with standard optical techniques. Scintillating screen monitors were mainly deployed in hadron and low energy electron machines where the intensity of optical transition radiation (OTR) is rather low. The experience from modern linac based light sources showed that OTR diagnostics might fail even for high energetic electron beams, thus making the use of scintillators again very attractive. This contribution summarizes results and trends from "Scintillating Screen Applications in Beam Diagnostics" workshop recently held in Darmstadt. In the first part an introduction to the scintillation mechanism will be given, including demands and limitations as e.g. the dynamic range and saturation. Thereafter a brief overview on actual screen monitor applications at electron and hadron accelerators will be presented.

Slides WEOB01 [14.721 MB]