DIPAC2011 - List of Authors (Bravin, E.)

Paper

Title

Page

Development of a Silicon Detector Monitor for the Superconducting Upgrade of the REX-ISOLDE Heavy-Ion Linac at CERN

131

F. Zocca
IEM, Madrid, Spain
E. Bravin, M.A. Fraser, D. Voulot, F.J.C. Wenander, F. Zocca
CERN, Geneva, Switzerland
M. Pasini
Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Leuven, Belgium

A silicon detector monitor has been developed and tested in the frame of the beam diagnostics development program for the HIE-ISOLDE superconducting upgrade of the REX-ISOLDE heavy-ion linac at CERN. The monitor is intended for beam energy and timing measurements as well as for phase scanning of the superconducting cavities. Tests have been performed with a stable ion beam, composed of carbon, oxygen and neon ions accelerated to energies from 300 keV/u to 2.85 MeV/u. The silicon detector was placed directly in the beam line and tested with a beam which was strongly attenuated to simulate the single particle detection regime for which the monitor is intended to finally function. The energy measurements performed allowed for beam spectroscopy and ion identification with a resolution of 3%. The principle of cavity phase scanning was also demonstrated with the REX 7-gap resonator thanks to the accurate peak energy identification. The time structure of the beam, characterized by a bunch period of 9.87 ns, was measured with a resolution better than 200 ps. This paper describes the results from all these tests as well as providing details of the detector.

MOPD59

A New Fast Acquisition Profile for the LHC and the SPS

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.

TUPD49

Performance of Parabolic and Diffusive OTR Screens at the CLIC Test Facility 3

413

M. Olvegård, B. Bolzon, E. Bravin, S. Burger, A.E. Dabrowski, T. Lefèvre
CERN, Geneva, Switzerland
C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

At the CLIC Test Facility 3, OTR screens are commonly used in beam imaging systems for energy and energy spread characterization in dedicated spectrometer lines. In these lines the horizontal beam size is typically of the order of one centimeter. Already in 2005 a limitation was observed resulting from a strong dependence of the intensity of the light captured by the camera, on the position on the screen (vignetting). The severity of this effect increases with the electron energy, as the aperture of the optical system is finite and the OTR photons are emitted in a small cone of 1/γ angle. To mitigate this effect, different shapes and surface polishing of the screens were investigated. Parabolic and diffusive OTR radiators were tested in several spectrometer lines all along the CTF3 complex. The results are presented in this paper.

TUPD82

First Results of the LHC Collision Rate Monitors

497

E. Bravin, S. Bart Pedersen, A. Boccardi, S. Burger, C. Dutriat
CERN, Geneva, Switzerland
L.R. Doolittle, H.S. Matis, M. Placidi, A. Ratti, H. Yaver, T. stezelberger
LBNL, Berkeley, California, USA
R. Miyamoto
BNL, Upton, Long Island, New York, USA

Funding: This work is partially supported by the US DoE through US-LARP
The aim of CERN’s large hadron collider (LHC) is to collide protons and heavy ions with centre of mass energies up to 14 zTeV. In order to monitor and optimize the collision rates special detectors have been developed and installed around the four luminous interaction regions. Due to the different conditions at the high luminosity experiments, ATLAS and CMS, and the low luminosity experiments, ALICE and LHC-b, two very different types of monitors are used, a fast ionisation chamber (BRAN-A) and a Cd-Te solid state detector (BRAN-B) respectively. Moreover in order to cope with the low collision rates foreseen for the initial run a third type of monitor, based on a simple scintillating pad, was installed in parallel with the BRAN-A. This contribution illustrates the results obtained during the 2010 run with an outlook for 2011 and beyond.

WEOA04

Synchrotron Radiation Measurements at the CERN LHC

550

F. Roncarolo, S. Bart Pedersen, A. Boccardi, E. Bravin, A. Guerrero, A. Jeff, T. Lefèvre, A. Rabiller
CERN, Geneva, Switzerland
A.S. Fisher
SLAC, Menlo Park, California, USA

The CERN LHC is equipped with two systems (one for each beam) designed to image the synchrotron radiation emitted by protons and heavy ions. After their commissioning in 2009, the detectors were extensively used and studied during the 2010 run. This allowed preliminary limits in terms of sensitivity, accuracy and resolution to be established. The upgrade to an intensified video camera capable of gating down to 25ns permitted the acquisition of single bunch profiles even with an LHC proton pilot bunch (~5·10⁹ protons) at 450 GeV or a single lead ion bunch (~10⁸ ions) from about 2 TeV. Plans for the optimization and upgrade of the system will be discussed. Since few months, part of the extracted light is deviated to the novel Longitudinal Density Monitor (LDM), consisting in an avalanche photo-diode detector providing a resolution better than 100 ps. The LDM system description will be complemented with the promising first measurement results.

Slides WEOA04 [6.398 MB]

Paper	Title	Page
MOPD36	Development of a Silicon Detector Monitor for the Superconducting Upgrade of the REX-ISOLDE Heavy-Ion Linac at CERN	131
	F. Zocca IEM, Madrid, Spain E. Bravin, M.A. Fraser, D. Voulot, F.J.C. Wenander, F. Zocca CERN, Geneva, Switzerland M. Pasini Instituut voor Kern- en Stralingsfysica, K. U. Leuven, Leuven, Belgium
	A silicon detector monitor has been developed and tested in the frame of the beam diagnostics development program for the HIE-ISOLDE superconducting upgrade of the REX-ISOLDE heavy-ion linac at CERN. The monitor is intended for beam energy and timing measurements as well as for phase scanning of the superconducting cavities. Tests have been performed with a stable ion beam, composed of carbon, oxygen and neon ions accelerated to energies from 300 keV/u to 2.85 MeV/u. The silicon detector was placed directly in the beam line and tested with a beam which was strongly attenuated to simulate the single particle detection regime for which the monitor is intended to finally function. The energy measurements performed allowed for beam spectroscopy and ion identification with a resolution of 3%. The principle of cavity phase scanning was also demonstrated with the REX 7-gap resonator thanks to the accurate peak energy identification. The time structure of the beam, characterized by a bunch period of 9.87 ns, was measured with a resolution better than 200 ps. This paper describes the results from all these tests as well as providing details of the detector.

MOPD59	A New Fast Acquisition Profile for the LHC and the SPS	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.

TUPD49	Performance of Parabolic and Diffusive OTR Screens at the CLIC Test Facility 3	413
	M. Olvegård, B. Bolzon, E. Bravin, S. Burger, A.E. Dabrowski, T. Lefèvre CERN, Geneva, Switzerland C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	At the CLIC Test Facility 3, OTR screens are commonly used in beam imaging systems for energy and energy spread characterization in dedicated spectrometer lines. In these lines the horizontal beam size is typically of the order of one centimeter. Already in 2005 a limitation was observed resulting from a strong dependence of the intensity of the light captured by the camera, on the position on the screen (vignetting). The severity of this effect increases with the electron energy, as the aperture of the optical system is finite and the OTR photons are emitted in a small cone of 1/γ angle. To mitigate this effect, different shapes and surface polishing of the screens were investigated. Parabolic and diffusive OTR radiators were tested in several spectrometer lines all along the CTF3 complex. The results are presented in this paper.

TUPD82	First Results of the LHC Collision Rate Monitors	497
	E. Bravin, S. Bart Pedersen, A. Boccardi, S. Burger, C. Dutriat CERN, Geneva, Switzerland L.R. Doolittle, H.S. Matis, M. Placidi, A. Ratti, H. Yaver, T. stezelberger LBNL, Berkeley, California, USA R. Miyamoto BNL, Upton, Long Island, New York, USA
	Funding: This work is partially supported by the US DoE through US-LARP The aim of CERN’s large hadron collider (LHC) is to collide protons and heavy ions with centre of mass energies up to 14 zTeV. In order to monitor and optimize the collision rates special detectors have been developed and installed around the four luminous interaction regions. Due to the different conditions at the high luminosity experiments, ATLAS and CMS, and the low luminosity experiments, ALICE and LHC-b, two very different types of monitors are used, a fast ionisation chamber (BRAN-A) and a Cd-Te solid state detector (BRAN-B) respectively. Moreover in order to cope with the low collision rates foreseen for the initial run a third type of monitor, based on a simple scintillating pad, was installed in parallel with the BRAN-A. This contribution illustrates the results obtained during the 2010 run with an outlook for 2011 and beyond.

WEOA04	Synchrotron Radiation Measurements at the CERN LHC	550
	F. Roncarolo, S. Bart Pedersen, A. Boccardi, E. Bravin, A. Guerrero, A. Jeff, T. Lefèvre, A. Rabiller CERN, Geneva, Switzerland A.S. Fisher SLAC, Menlo Park, California, USA
	The CERN LHC is equipped with two systems (one for each beam) designed to image the synchrotron radiation emitted by protons and heavy ions. After their commissioning in 2009, the detectors were extensively used and studied during the 2010 run. This allowed preliminary limits in terms of sensitivity, accuracy and resolution to be established. The upgrade to an intensified video camera capable of gating down to 25ns permitted the acquisition of single bunch profiles even with an LHC proton pilot bunch (~5·10⁹ protons) at 450 GeV or a single lead ion bunch (~10⁸ ions) from about 2 TeV. Plans for the optimization and upgrade of the system will be discussed. Since few months, part of the extracted light is deviated to the novel Longitudinal Density Monitor (LDM), consisting in an avalanche photo-diode detector providing a resolution better than 100 ps. The LDM system description will be complemented with the promising first measurement results.
	Slides WEOA04 [6.398 MB]