Bonn 2010 – wissenschaftliches Programm
HK 22.3: Vortrag
Dienstag, 16. März 2010, 14:45–15:00, HG IX
Development of a beam profile monitor for degraded beams at HISPEC/DESPEC at FAIR — •Michael Pfeiffer1, Gheorghe Pascovici1, Nigel Warr1, Farheen Naqvi2, and Jan Jolie1 — 1IKP, Universität zu Köln — 2GSI, Darmstadt
In the context of the HISPEC/DESPEC part of NUSTAR at FAIR-GSI we are investigating the development of new tracking detectors to reconstruct the kinematics of the ions after they are decelerated to energies of about 5MeV/u. The main issue encountered with slowing down relativistic beams is the energy straggling and the spread in space and direction of these beams. Thereby, new generations of beam-characterization detectors are requested to allow not only the precise determination of the position of an incoming ion and its energy loss but also the arrival time (for time of flight purposes-TOF) and if possible to reconstruct the ion track (Beam Tracking Detector), as well.
Our solution uses the secondary electrons generated by ions passing through a thin sheet of material (80−120µ g/cm2). Two basic units of large sensitive area (∼80x100mm2) are placed downstream of the beam axis and electrostatic mirrors project the secondary electrons on the position sensitive detectors.
The transparency of each component is ∼90%, making the overall transparency of one unit ∼70%. We aim to get an angular resolution of about 1.5−2.5 · 10−2 steradian with a sub-ns resolution for the TOF. Even though the S/N ratio per current pulse is very promising, we are facing a very high pulse shot noise at the MCP outputs. The source of these additional electrons is under investigation.