CERN, Geneva
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
IN2P3-LAPP, Annecy-le-Vieux
DESY, Hamburg
SLAC, Menlo Park, California
The CLIC BDS is experiencing the careful revision from a large number of world wide experts. This was particularly enhanced by the successful CLIC'08 workshop held at CERN. Numerous new ideas, improvements and critical points are arising, establishing the path towards the Conceptual Design Report by 2010.
JAI, Oxford
ATOMKI, Debrecen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
We present the results of beam tests of the FONT4 ILC prototype intra-train beam feedback system. The system comprises a stripline BPM, a fast analogue BPM signal processor, a custom FPGA-based digital feedback board, a high-power fast-response drive amplifier, and a stripline kicker. The hardware was deployed at the Accelerator Test Facility at KEK. Trains comprising three electron bunches were extracted from the ATF damping ring, with bunch spacing c. 150ns. The feedback loop was closed by measuring the position of bunch 1 and correcting bunches 2 and 3. We report the performance of the feedback, including gain studies, the correction dynamic range, latency measurement, and quality of the beam position correction. The system achieved micron-level bunch stabilisation with a latency of c. 140ns.
JAI, Oxford
We review the current status of the collimation system of the Compact Linear Collider (CLIC). New calculations are done to study the survivability of the CLIC energy spoiler in case of impact of a full bunch train considering the most recent beam parameters. The impact of the collimator wakefields on the luminosity is also studied using the updated collimator apertures, and we evaluate the beam position jitter tolerance that is required to preserve the nominal luminosity. Moreover, assuming the new collimation depths, we evaluate the collimation efficiency.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
JAI, Oxford
The postlinac energy collimation system of the Compact Linear Collider (CLIC) protects the machine by intercepting mis-steered beams due to possible failure modes in the linac. The collimation is based in a spoiler-absorber scheme. The mission of the spoiler is to protect the main downstream absorber by dispersing the beam, via multiple Coulomb scattering, in case of a direct hit. We present the design of energy spoilers for CLIC, considering the following requirements: spoiler survival to the deep impact of an entire bunch train, and minimisation of spoiler wakefield effects during normal operation. Different configurations of the spoiler are studied in order to achieve an optimum performance.
JAI, Oxford
ATOMKI, Debrecen
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
We present the design of prototype fast beam position monitor (BPM) signal processors for use in inter-bunch beam-based feedbacks for linear colliders and electron linacs. We describe the FONT4 intra-train beam-based digital position feedback system prototype deployed at the Accelerator test facility (ATF) extraction line at KEK, Japan. The system incorporates a fast analogue beam position monitor front-end signal processor, a digital feedback board, and a fast kicker-driver amplifier. The total feedback system latency is less than 150ns, of which less than 10ns is used for the BPM processor. We report preliminary results of beam tests using electron bunches separated by c. 150ns. Position resolution of order 1 micron is obtained.
JAI, Oxford
The major goals of the final focus test beam line facility ATF2 are to provide electron beams with a few tens nanometer beam sizes and beam stability control at the nanometer level. In order to achieve such a level of stability beam based feedback systems are necessary at different timescales to correct static and dynamic effects. In particular, we present the design of intra-train feedback systems to correct the impact of fast jitter sources. We study a bunch-to-bunch feedback system to be installed at the extraction line to combat the ring extraction transverse jitters. In addition, we design a bunch-to-bunch feedback system at the interaction point for correction of position jitter due to the fast vibration of the magnets in the final focus. Optimum feedback software algorithms are discussed and simulation results are presented.
SLAC, Menlo Park, California
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
JAI, Oxford
KEK, Ibaraki
IHEP Beijing, Beijing
LAL, Orsay
Royal Holloway, University of London, Surrey
IN2P3-LAPP, Annecy-le-Vieux
OXFORDphysics, Oxford, Oxon
ATOMKI, Debrecen
CERN, Geneva
DESY, Hamburg
Fermilab, Batavia
Kyungpook National University, Daegu
PAL, Pohang, Kyungbuk
Kyoto ICR, Uji, Kyoto
ICEPP, Tokyo
University of Tokyo, Tokyo
UCL, London
BNL, Upton, Long Island, New York
Tohoku University, Graduate School of Science, Sendai
UMAN, Manchester
Hiroshima University, Graduate School of Science, Higashi-Hiroshima
Cockcroft Institute, Warrington, Cheshire
ATF2 is a final-focus test beam line that attempts to focus the low-emittance beam from the ATF damping ring to a beam size of about 37 nm, and at the same time to demonstrate nm beam stability, using numerous advanced beam diagnostics and feedback tools. The construction is well advanced and beam commissioning of ATF2 has started in the second half of 2008. ATF2 is constructed and commissioned by ATF international collaborations with strong US, Asian and European participation.
