Beam Secondary Shower Acquisition Design for the CERN High Accuracy Wire Scanner

866/2-D05 (CERN)



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      Beam Secondary Shower Acquisition Design for the CERN High Accuracy Wire Scanner

      The current Beam Wire Scanner (BWS) generation features high operational complexity and performance is partly limited by the secondary shower detectors and acquisition systems. These are traditionally based on scintillators attached to a Photo-Multiplier Tube (PMT) through optical filters. The detectors require tuning according to the beam conditions (energy and intensity) prior to a measurement to avoid the saturation of the readout electronics, located on the surface buildings. Under these circumstances many configurations lead to a poor SNR and reduced resolution, directly affecting the measurement reliability. In addition, bunch-by-bunch profile measurements are compromised by the use of long coaxial lines for signal transmission, which reduce the system bandwidth and leads to bunch pile-up.
      This seminar presents the design of an upgraded secondary shower acquisition system for the LIU-BWS. This includes the study of a novel detector technology for the BWS based on polycrystalline Chemical Vapour Deposited (pCVD) diamond and the implementation of two acquisition system prototypes. The presentation includes: a review of the operational acquisition systems; the identification of limitations of the current systems and presents particle physics simulations with FLUKA for a better understanding of the secondary particles shower behaviour.

      The acquisition system implemented for the pCVD diamond and a multiple-PMT detector performed high dynamic range signal acquisition and digitisation in the tunnel with a radiation-hard front-end nearby the detectors. The digital data was transmitted afterwards to the counting room through a 4.8Gbps optical link. This novel scheme not only allows for low-noise measurements, but also avoids the bandwidth restrictions imposed by long coaxial lines and greatly simplifies the scanner operation. Measurements using pCVD diamond detectors for the detection of secondary particles in SPS BWS, over a wide range of energies and intensities, will be presented.

      Speaker: Jose Luis Sirvent Blasco (University of Liverpool (GB))