DIPAC2011 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MOPD14	Calibration of the Electrostatic Beam Position Monitors for VEPP-2000	vacuum, pick-up, electron, positron	68
	Yu. A. Rogovsky, I. Nesterenko BINP SB RAS, Novosibirsk, Russia
	The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ± 6 mm square. Results for these portions of the calibration are presented.
	Poster MOPD14 [0.393 MB]

MOPD59	A New Fast Acquisition Profile for the LHC and the SPS	radiation, betatron, injection, alignment	182
	S. Burger, A. Boccardi, E. Bravin, A. Rabiller, R.S. Sautier CERN, Geneva, Switzerland
	The beam profile is an important parameter for the tuning of particle accelerators. These profiles are often obtained by imaging optical transition radiation from a radiator on a CCD camera. This technique works well for slow acquisitions, but in some cases it is necessary to acquire profiles with higher rates where such standard cameras are no longer suitable. In our case the aim is to sample the profiles on a turn-by-turn basis which, for the CERN-SPS, corresponds to ~44 kHz. For this reason we have developed a fast detector based on a recent Hamamatsu linear CCD and an optical system using cylindrical lenses. The readout electronics is based on CERN developed, radiation tolerant components and the digital data is transmitted to an acquisition board outside of the tunnel by mean of optical fibres. This contribution describes the system and shows the performance obtained on a test bench.

TUPD38	Design of a Single-Shot Prism Spectrometer in the Near- and Mid-Infrared Wavelength Range for Ultra-Short Bunch Length Diagnostics	electron, simulation, radiation, diagnostics	386
	C. Behrens DESY, Hamburg, Germany A.S. Fisher, J.C. Frisch, A. Gilevich, H. Loos, J. Loos SLAC, Menlo Park, California, USA
	The successful operation of high-gain free-electron lasers (FEL) relies on the understanding, manipulation, and control of the parameters of the driving electron bunch. Present and future FEL facilities have the tendency to push the parameters for even shorter bunches with lengths below 10 fs and charges well below 100 pC. This is also the order of magnitude at laser-driven plasma-based electron accelerators. Devices to diagnose such ultra-short bunches even need longitudinal resolutions smaller than the bunch lengths, i.e. in the range of a few femtoseconds. This resolution is currently out of reach with time-domain diagnostics like RF-based deflectors, and approaches in the frequency-domain have to be considered to overcome this limitation. Our approach is to extract the information on the longitudinal bunch profile by means of infrared spectroscopy using a prism as dispersive element. In this paper, we present the design considerations on a broadband single-shot spectrometer in the near- and mid-infrared wavelength range (0.8 - 39.0 μm).

TUPD48	Transition Radiation from a Cylindrical Target and Transverse Beam Size Diagnostics	target, electron, radiation, FEL	410
	A. Potylitsyn TPU, Tomsk, Russia L.G. Sukhikh DESY, Hamburg, Germany
	For modern X-ray FELs like LCLS in SLAC, FLASH in DESY and constructed ones like European X-FEL the transverse beam profile diagnostics using well-known optical Transition Radiation (TR) is not a trivial task because of a short bunch length and instabilities. Due to these reasons a bunch emits any kind of radiation coherently that makes it impossible to determine transverse profile of such bunch. One may use radiation with wavelengths shorter than bunch length (e.g. EUV) to avoid the problem of radiation coherence. Because of a high quality of mirrors in that region needed to construct proper optical line we propose to use a cylindrical target instead of flat one. TR generated by the cylindrical target is wider than the one from the flat target. But in this case the radiation generated by particles with different impact-parameters relative to a cylinder axes depends on the point of interaction. Proper choice of cylinder parameters allows to obtain beam profile image without any additional optics. In this report we present the simulation results and show how the radiation from the cylindrical target may be used for the bunch transverse profile diagnostics with good space resolution.

TUPD71	Combined Approach using Closed-Orbit and Multiturn Data for Model-Independent and Fast Beam Optics Determination in Storage Rings	closed-orbit, betatron, storage-ring, dipole	473
	B. Riemann, P. Grete, H. Huck, A. Nowaczyk, T. Weis DELTA, Dortmund, Germany
	Multiturn-capable BPMs have been used successfully for characterization of storage ring beam optics. While their use eases determination of optical parameters (e.g. beta function and phase) by observation of non ring-periodic beam centroid oscillation, the installation of multiturn electronics in all storage ring BPMs causes a high monetary effort. The presented method aims at combining multiturn and closed-orbit measurement methods in a cost-effective way. This is done using a single drift section in the ring, being equipped with two multiturn BPMs at its ends. Measuring the centroid motion in the full transverse phase space, one can completely determine all local beam optics parameters inside the drift space. Then, four additional dipole correctors inside this drift are used to create closed-orbit perturbations along the ring. Because of the known drift optics, it is then possible to extract all data that would be available if all storage ring BPMs were multiturn-capable, by using only closed-orbit BPM data of the mentioned four perturbations (incl. betatron coupling). This fast and model-independent approach may be increased in accuracy by a coupled bunch feedback system.

WEOB03	Single-shot Resolution of X-ray Monitor using Coded Aperture Imaging	photon, emittance, synchrotron, synchrotron-radiation	561
	J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi KEK, Ibaraki, Japan J.P. Alexander, M.A. Palmer, D.P. Peterson, N.T. Rider CLASSE, Ithaca, New York, USA G.S. Varner UH, Honolulu, HI, USA
	We report on tests of an x-ray beam size monitor based on coded aperture imaging. This technique uses a mask pattern to modulate incoming light, with the resulting image being deconvolved through the mask and detector responses, including the effects of diffraction and attenuation materials in the path, over the spectral and angular distribution of the synchrotron radiation generated by the beam. We have tested mask patterns called URA masks, which have relatively flat spatial frequency response, and an open aperture of 50% for high-flux throughput, enabling single-shot (bunch-by-bunch, turn-by-turn) measurements without the need for heat-sensitive mirrors. Bunch size measurements of ~10 micron bunches with single-shot (statistics-dominated) resolutions of ~2.5 microns have been demonstrated at CesrTA, and single-shot measurements with similar or better resolution of beams in the ~5 micron range are being aimed for at the ATF2. A beam-size monitor based on these principles is also being designed for the SuperKEKB low-emittance rings. We will present estimated single-shot resolutions, along with a comparison to single-shot resolution measurements made at CesrTA.
	Slides WEOB03 [1.694 MB]

Paper

Title

Other Keywords

Page

MOPD14

Calibration of the Electrostatic Beam Position Monitors for VEPP-2000

vacuum, pick-up, electron, positron

68

Yu. A. Rogovsky, I. Nesterenko
BINP SB RAS, Novosibirsk, Russia

The basic requirement for the VEPP-2000 Beam Position Monitor (BPM) is the measurement of the beam orbit with 0.1 mm precision. To improve the measurement accuracy, the response of the electrostatic BPMs (pickups) were mapped in the laboratory before they were installed in the VEPP-2000 ring. The wire method for the sensitivity calibration and position-to-signal mapping is used. The test stand consists of high frequency coaxial switches to select each pickup electrode, movable antenna to simulate the beam, signal source, spectrum analyzer to measure the pickup signals, and analysis software. This calibration showed possibility of required accuracy. During calibration the electrical center of the different BPMs was measured with respect to the mechanical center. Conversion between the BPM signal and the actual beam position is done by using polynomial expansions fit to the mapping data within ± 6 mm square. Results for these portions of the calibration are presented.

Poster MOPD14 [0.393 MB]

MOPD59

A New Fast Acquisition Profile for the LHC and the SPS

radiation, betatron, injection, alignment

182

S. Burger, A. Boccardi, E. Bravin, A. Rabiller, R.S. Sautier
CERN, Geneva, Switzerland

The beam profile is an important parameter for the tuning of particle accelerators. These profiles are often obtained by imaging optical transition radiation from a radiator on a CCD camera. This technique works well for slow acquisitions, but in some cases it is necessary to acquire profiles with higher rates where such standard cameras are no longer suitable. In our case the aim is to sample the profiles on a turn-by-turn basis which, for the CERN-SPS, corresponds to ~44 kHz. For this reason we have developed a fast detector based on a recent Hamamatsu linear CCD and an optical system using cylindrical lenses. The readout electronics is based on CERN developed, radiation tolerant components and the digital data is transmitted to an acquisition board outside of the tunnel by mean of optical fibres. This contribution describes the system and shows the performance obtained on a test bench.

TUPD38

Design of a Single-Shot Prism Spectrometer in the Near- and Mid-Infrared Wavelength Range for Ultra-Short Bunch Length Diagnostics

electron, simulation, radiation, diagnostics

386

C. Behrens
DESY, Hamburg, Germany
A.S. Fisher, J.C. Frisch, A. Gilevich, H. Loos, J. Loos
SLAC, Menlo Park, California, USA

The successful operation of high-gain free-electron lasers (FEL) relies on the understanding, manipulation, and control of the parameters of the driving electron bunch. Present and future FEL facilities have the tendency to push the parameters for even shorter bunches with lengths below 10 fs and charges well below 100 pC. This is also the order of magnitude at laser-driven plasma-based electron accelerators. Devices to diagnose such ultra-short bunches even need longitudinal resolutions smaller than the bunch lengths, i.e. in the range of a few femtoseconds. This resolution is currently out of reach with time-domain diagnostics like RF-based deflectors, and approaches in the frequency-domain have to be considered to overcome this limitation. Our approach is to extract the information on the longitudinal bunch profile by means of infrared spectroscopy using a prism as dispersive element. In this paper, we present the design considerations on a broadband single-shot spectrometer in the near- and mid-infrared wavelength range (0.8 - 39.0 μm).

TUPD48

Transition Radiation from a Cylindrical Target and Transverse Beam Size Diagnostics

target, electron, radiation, FEL

410

A. Potylitsyn
TPU, Tomsk, Russia
L.G. Sukhikh
DESY, Hamburg, Germany

For modern X-ray FELs like LCLS in SLAC, FLASH in DESY and constructed ones like European X-FEL the transverse beam profile diagnostics using well-known optical Transition Radiation (TR) is not a trivial task because of a short bunch length and instabilities. Due to these reasons a bunch emits any kind of radiation coherently that makes it impossible to determine transverse profile of such bunch. One may use radiation with wavelengths shorter than bunch length (e.g. EUV) to avoid the problem of radiation coherence. Because of a high quality of mirrors in that region needed to construct proper optical line we propose to use a cylindrical target instead of flat one. TR generated by the cylindrical target is wider than the one from the flat target. But in this case the radiation generated by particles with different impact-parameters relative to a cylinder axes depends on the point of interaction. Proper choice of cylinder parameters allows to obtain beam profile image without any additional optics. In this report we present the simulation results and show how the radiation from the cylindrical target may be used for the bunch transverse profile diagnostics with good space resolution.

TUPD71

Combined Approach using Closed-Orbit and Multiturn Data for Model-Independent and Fast Beam Optics Determination in Storage Rings

closed-orbit, betatron, storage-ring, dipole

473

B. Riemann, P. Grete, H. Huck, A. Nowaczyk, T. Weis
DELTA, Dortmund, Germany

Multiturn-capable BPMs have been used successfully for characterization of storage ring beam optics. While their use eases determination of optical parameters (e.g. beta function and phase) by observation of non ring-periodic beam centroid oscillation, the installation of multiturn electronics in all storage ring BPMs causes a high monetary effort. The presented method aims at combining multiturn and closed-orbit measurement methods in a cost-effective way. This is done using a single drift section in the ring, being equipped with two multiturn BPMs at its ends. Measuring the centroid motion in the full transverse phase space, one can completely determine all local beam optics parameters inside the drift space. Then, four additional dipole correctors inside this drift are used to create closed-orbit perturbations along the ring. Because of the known drift optics, it is then possible to extract all data that would be available if all storage ring BPMs were multiturn-capable, by using only closed-orbit BPM data of the mentioned four perturbations (incl. betatron coupling). This fast and model-independent approach may be increased in accuracy by a coupled bunch feedback system.

WEOB03

Single-shot Resolution of X-ray Monitor using Coded Aperture Imaging

photon, emittance, synchrotron, synchrotron-radiation

561

J.W. Flanagan, A. Arinaga, H. Fukuma, H. Ikeda, T.M. Mitsuhashi
KEK, Ibaraki, Japan
J.P. Alexander, M.A. Palmer, D.P. Peterson, N.T. Rider
CLASSE, Ithaca, New York, USA
G.S. Varner
UH, Honolulu, HI, USA

We report on tests of an x-ray beam size monitor based on coded aperture imaging. This technique uses a mask pattern to modulate incoming light, with the resulting image being deconvolved through the mask and detector responses, including the effects of diffraction and attenuation materials in the path, over the spectral and angular distribution of the synchrotron radiation generated by the beam. We have tested mask patterns called URA masks, which have relatively flat spatial frequency response, and an open aperture of 50% for high-flux throughput, enabling single-shot (bunch-by-bunch, turn-by-turn) measurements without the need for heat-sensitive mirrors. Bunch size measurements of ~10 micron bunches with single-shot (statistics-dominated) resolutions of ~2.5 microns have been demonstrated at CesrTA, and single-shot measurements with similar or better resolution of beams in the ~5 micron range are being aimed for at the ATF2. A beam-size monitor based on these principles is also being designed for the SuperKEKB low-emittance rings. We will present estimated single-shot resolutions, along with a comparison to single-shot resolution measurements made at CesrTA.

Slides WEOB03 [1.694 MB]