Technical Design Report Super Fragment Separator

DRAFT
SIS3301. An example of measured beam profile in x is shown in Figure 2.4.85 (right panel).
Figure 2.4.85: Left panel: BPD prototype with front-end electronics. Right panel: Measured x-direction
beam profile of 12 C ions at 400 MeV/u with an intensity of 1.6·10 9 ion per 300 ns.
In addition, the BPD was tested as in-beam detectors for experiments using slow-extraction beams
at 3 MHz rate. Similar to time projection chamber (TPC) detectors, in this case it was working as
position-sensitive detector recording single ions.
As in the case of the TPC described in section 2.4.6.2 the readout can be improved to reach a
dead-time free readout speed of 160 kHz/wire by making use of the CBM-XYTER ASIC readout
boards.
2.4.6.4 Luminosity monitor (SEETRAM)
We want to perform luminosity measurements at two positions in the Super-FRS:
(i) in front of the quadrupole triplet prior to the target area,
(ii) at the entrance of the main separator (PF4).
(i) The intensity of the primary beam delivered by SIS12/18 or SIS100/300 will be measured
outside the target zone. The advantage of this arrangement is the enhanced accessibility, and to
keep the hot zone technically as simple as possible. Two ladders for mounting are foreseen in this
diagnosis box, both covering detectors with an active area of (10 x 10) cm². The first one will be
equipped with a Resonant Beam Transformer and a Diamond counting detector. The second one
houses a SEETRAM (Secondary Electron Emission TRAnsmission Monitor) counter and a
Cryogenic Current Comparator. Resonant Beam Transformers [31] are the work-horses at the
current GSI facility. They can be used from 1 nC up to 1 µC with a resolution 10 pC (rms) for
bunches with a maximum pulse length of 1.5 µs. Thus, they are perfectly suited for the detection of
fast extracted pulses. Cryogenic Current Comparators are usable for DC currents down to about
100 pA [32] and can be used for the slow extracted beams. The SEETRAM counter [33] was
developed for the FRS. Its operation is based on the emission of secondary electrons from thin
metal foils (see Figure 2.4.86) by the passage of the projectiles. It can be used for slow and fast
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