JAI, Egham, Surrey
KEK, Ibaraki
Royal Holloway, University of London, Surrey
OXFORDphysics, Oxford, Oxon
The ATF extraction line laser-wire (LW) aims to achieve a micron-scale laser spot size and to verify that micron-scale beam profile measurements can be performed at the International Linear Collider beam delivery system. Recent upgrades to the LW system are presented together with recent results including the first use of the LW as a beam diagnostic tool.
ANL, Argonne, Illinois
Fermilab, Batavia, Illinois
An Optical Transition Radiation (OTR) detector has been installed in the Fermilab NuMI proton beamline, which operates at beam powers of up to ~300 kW, to obtain real-time, spill-by-spill beam profiles for neutrino production. A series of Optical Transition Radiation (OTR) detectors were design, constructed and installed in various beamlines at Fermilab and previous near-field OTR images of lower-intensity 120 GeV and 150 GeV protons with larger transverse beam size have been presented at BIW06 and IEEE NSS06. NuMI OTR images of 120 GeV protons for beam intensities up to 2.8·1013 at a spill rate of 0.5 Hz and small transverse beam size of ~1 mm (σ) are presented here. The NuMI OTR detector uses a 6 micron Kapton foil with 0.12 micron of aluminum which reduces beam scatter by 70% compared to an adjacent Secondary Emission Monitor (SEM). Beam profiles are extracted from the OTR images and compared to the adjacent SEM. The OTR detector provides two-dimensional beam shape such as ellipticity and tilt, as well as complementary beam centroid and beam intensity information. In addition, response of the OTR detector over different intensities and transverse positions is presented.
DESY, Hamburg
Fermilab, Batavia, Illinois
SLAC, Menlo Park, California
CEA, Gif-sur-Yvette
It is well known that an electron beam excites Higher Order Modes (HOMs) as it passes through an accelerating cavity~[panofsky68]. The properties of the excited signal depend not only on the cavity geometry, but on the charge and trajectory of the beam. It is, therefore, possible to use these signals as a monitor of the beam's position. Electronics were installed on all forty cavities present in the FLASH~[flashref] linac in DESY. These electronics filter out a mode known to have a strong dependence on the beam's position, and mix this down to a frequency suitable for digitisation. An analysis technique based on Singular Value Decomposition (SVD) was developed to calculate the beam's trajectory from the output of the electronics. The entire system has been integrated into the FLASH control system.
Jefferson Lab, Newport News, Virginia
UMD, College Park, Maryland
Optical Transition Radiation Interferometry (OTRI) has proven to be effective tool for measuring rms beam divergence. We present rms emittance measurement results of the 115 MeV energy recovery linac at the Thomas Jefferson National Laboratories Free electron Laser using OTRI. OTRI data from both near field beam images and far field angular distribution images give evidence of two spatial and angular distributions within the beam. Using the unique features of OTRI we segregate the two distributions of the beam and estimate separate rms emittance values for each component.