[show abstract][hide abstract] ABSTRACT: A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.
[show abstract][hide abstract] ABSTRACT: The laserwire system at the Accelerator Test Facility 2 (ATF2) is a transverse beam profile measurement system capable of measuring a micrometre-size electron beam. We present recent results demonstrating a measured ver-tical size of 1.16 ± 0.06 µm and a horizontal size of 110.1 ± 3.8 µm. Due to the high aspect ratio of the elec-tron beam, the natural divergence of the tightly focussed laser beam across the electron beam width requires the use of the full overlap integral to deconvolve the scans. For this to be done accurately, the propagation of the 150 mJ, 167 ps long laser pulses was precisely measured at a scaled virtual interaction point.
[show abstract][hide abstract] ABSTRACT: Transition radiation (TR) appearing when relativistic uniformly moving charged particle (or bunch of particles) crosses a boundary between two media with different di-electric properties is widely used as a tool for diagnostics of particle beams in modern accelerator facilities. The best resolution which can be achieved using beam profile mon-itors based on TR in optical wave range has a limitation caused by a spatial resolution of an optical system. Using a method based on analyzing a visibility of the TR Point Spread Function one can achieve a sub-micrometer reso-lution. In this report we shall represent the recent exper-imental results of a micron-scale beam size measurement at KEK-ATF2. We shall discuss the hardware status and future plans.
[show abstract][hide abstract] ABSTRACT: We present the results from the laserwire system at the Accelerator Test Facility 2 (ATF2) during recent operation after relocation to the virtual image point of the ATF2 fi-nal focus. The characterisation of the 150 mJ, 77 ps long laser pulses at a scaled virtual interaction point is used to deconvolve the transverse laserwire profile demonstrating a 1.16 ± 0.06 μm vertical electron beam profile. Horizontal laserwire scans were used in combination with the vertical scans to measure the electron beam size using a full over-lap integral model due to the problems presented by a large aspect ratio electron beam.
[show abstract][hide abstract] ABSTRACT: We present an outline of experiments being conducted at Oxford University on multiple-pulse, resonantly-enhanced laser plasma wakefield acceleration. This method of laser plasma acceleration uses trains of optimally spaced low energy short pulses to drive plasma oscillations and may enable laser plasma accelerators to be driven by compact and efficient fibre laser sources operating at high repetition rates.
[show abstract][hide abstract] ABSTRACT: We present the first results from the commissioning of the upgraded laser-wire experiment at the Accelerator Test Facility 2 (ATF-II) at KEK. A new laser transport line and beam diagnostics were used to collide 150 mJ, 167 ps long laser pulses with 1.28 GeV, 30 ps long electron bunches to measure the vertical transverse size. Additionally, a new detector was installed with a reduced area for lower background. Initial scans showing a convoluted beam size of 18.4 ± 0.4 μm were used to tune the electron beam optics and reduce this down to 8.0 ± 0.3 μm. Laser pulse energy and charge dependency were investigated showing a linear relationship in both with a minimum laser energy of 20 mJ required for adequate signal to make a laser-wire scan.
[show abstract][hide abstract] ABSTRACT: The KEK Accelerator test facility (ATF) extraction line laser-wire system has been upgraded last year allowing the measurement of micron scale transverse size electron beams. The most recent measurements using the upgraded system are presented. The ATF-II extraction line design call for the major upgrade of the existing laser-wire system. We report on the hardware upgrades, including the major hardware upgrades to the laser transport, the laser beam diagnostics line, and the mechanical control systems.
Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 01/2010; · 1.14 Impact Factor