Author: Smith, S.R.
Paper Title Page
TUPC12 Status of the Stripline Beam Position Monitor Development for the CLIC Drive Beam 384
  • A. Benot-Morell, L. Søby, M. Wendt
    CERN, Geneva, Switzerland
  • A. Benot-Morell, A. Faus-Golfe
    IFIC, Valencia, Spain
  • J.M. Nappa, S. Vilalte
    IN2P3-LAPP, Annecy-le-Vieux, France
  • S.R. Smith
    SLAC, Menlo Park, California, USA
  Funding: MINECO contract FPA2010-21456-C02-01, SEIC-2010-00028, U.S. Department of Energy contract DE-AC02-76SF00515
In collaboration with SLAC, LAPP and IFIC, a first prototype of a strip-line Beam Position Monitor (BPM) for the CLIC Drive Beam and its associated readout electronics has been successfully tested in the CLIC Test Facility linac (CTF3) at CERN. In addition, a modified prototype with downstream terminated strip-lines is under development to better suppress any unwanted RF signal interference. This paper presents the results of the beam tests, the most relevant design aspects for the modified strip-line BPM version and its expected performance.
poster icon Poster TUPC12 [1.729 MB]  
WEPC23 Design of an Ultra-Compact Stripline BPM Receiver using MicroTCA for LCLS-II at SLAC 731
  • C. Xu, S. Babel, S. L. Hoobler, R.S. Larsen, J.J. Olsen, S.R. Smith, T. Straumann, D. Van Winkle, A. Young
    SLAC, Menlo Park, California, USA
  Funding: Work supported by U.S. Department of Energy under Contract Numbers DE-AC02-06CH11357 and DE-AC02-76SF00515
The Linac Coherent Light Source II (LCLS II) is a free electron laser (FEL) light source. LCLS II will be able to produce 0.5 to 77 Angstroms soft and hard x-rays. In order to achieve this high level of performance, the electron beam needs to be stable and accurate. The LCLS II stripline BPM system has a dynamic range of 10pC to 1nC beam charge. The system has a 3.5 micrometer resolution at 250pC beam charge in an one inch diameter stripline BPM structure. The BPM system uses the MicroTCA physics platform that consists of analog front-end (AFE) and 16-bit analog to digital convertor (ADC) module. The paper will discuss the hardware design, architecture, and performance measurements on the SLAC LINAC. The hardware architecture includes bandpass filter at 300MHz with 15 MHz band-width, and BPM calibration process without communicating with the CPU module. The system will be able to process multibunch beams with 40ns spacing.
poster icon Poster WEPC23 [1.769 MB]  
Low vs High Q Cavity BPMs  
  • S.R. Smith
    SLAC, Menlo Park, California, USA
  Steve summarized the pros and cons of high vs. low Q cavity BPM pickups very comprehensively. He included a few real-world examples on mode-leakage, dynamic range and expected resolution by acquiring multiple samples of the waveform. The latter favors a high-Q BPM resonator, which he claims will improve the resolution, i.e. effective number of bits, by using more ADC samples n on the waveform by ln(n)/2. Other arguments of Steve on the Nyquist theorem and signal aliasing also favors the use of a high-Q BPM. Most colleagues followed his view: try to use a high-Q cavity BPM!  
slides icon Slides FRWAJ2 [0.273 MB]