CERN Beam Test Preparation Guide

 

                                               

CREAM has been accepted to be behind AMS and run in a parasitic mode for the October beam test at CERN.  The current schedule is available at the following URL: http://sps-schedule.web.cern.ch/sps-schedule/2002/p3a.gif.  There will be 4 experiments, AMS-RICH, AMS-Tracker, AMS-TOF, and CREAM charge detectors, all located in a stretch of ~5 m along the beam line.  The main user is AMS-RICH, taking about 2.5 m along the beam line.  The beam area is very crowded and we need to make our system as thin as possible, fitting in less than 1 m along the beam line.  The clearance to beam-left and to beam-right from the beam axis is about 1 m on each side.   The height of the beam axis from the floor is estimated to be ~1.26 m.  We will know the exact numbers once our AMS colleagues visit the site to measure the area next week.

 

  • The beam line is the H8 line with the T6 target.
  • The primary Pb beam intensity on the production target (10 cm–30 cm Be) is 107 nuclei/s.
  • The momentum resolution (dp/p) of the beam line is adjustable between 0.15% and 1.5%.
  • We will use fragments of 20 GeV/N Pb nuclei.
  • Fragment rate for low-Z fragments is ~48–(A–1) providing (at ~8 GeV/N) about 250 H/spill, 1 D/spill, 1 3He/hour, 1 4He/week, with intensity increasing for decreasing rigidity. The total count rate per nuclear fragment should be on the order of 1000/spill or higher for most nuclei of interest. Roughly, the ratio of production cross-sections of He/C/Fe is 30/10/1 – similar to cosmic rays. Protons should be available at all momenta up to the beam rigidity.  Light nuclei should be available mostly at low rigidity or near beam rigidity but not between the two.  Nuclei with A/Z~2 and with rigidity close to the beam rigidity will be transported to the detectors.  Nuclei heavier than Fe should not be transported by the beam line as they have A/Z>2 (2.5 for Pb).

 

Since Sasha provides the trigger counters for RICH as he did for us in July, you can assume a similar trigger setup for now and we can get more details when he comes back from Moscow at the end of this month.

 

As for the counting room, the NA45 barrack, assigned for AMS, is a rather dirty empty space in one corner (used so far as a workshop) and another cleaner space, but crowded with computers which are likely to stay.  Considering 3 AMS groups, there will be no room for us in NA45 unless the NA45 collaboration moves out and cleans the area.  We are still working on this issue, but we may have to settle outside the counting barrack, downstairs where there is plenty of space available close to the experimental area.  A typical cable run from the counting room to the detector in the beam enclosure is about 30 m.   It could be shorter if we settle close to the enclosure, but we should prepare long enough cables to fit either scenario.

 

For additional general information, see http://sps-schedule.web.cern.ch/sps-schedule/.