DIPAC2011 - List of Authors (Fisher, A.S.)

Paper

Title

Page

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

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
TUPD38	Design of a Single-Shot Prism Spectrometer in the Near- and Mid-Infrared Wavelength Range for Ultra-Short Bunch Length 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).

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]