PHENIX%20Status

1
PHENIX Status

• John Haggerty
• Brookhaven National Laboratory

2
HBD

• The HBD group has analyzed data taken before we
  switched to field last week, and Ilia
  Ravinonovich has analyzed single electrons from
  HBD resolved Dalitz pairs showing 20 pe per
  single electron
• He has now looked at the HBD in field and
  reverse bias

3
Muons

• Todd Kempel has run muon arm production on our 2
  deep muon trigger stream12k J/? reconstructed
  after two weeks of running

4
Electrons

• The calibration is key to the calorimeter, being
  done by Kenichi Karatsu
• 2.2x106 p0 reconstructed, about half what wed
  like for calibration (after two weeks of running)
  

5
DAQ performance

• The DAQ and triggers are tuned up and
  improvements to livetime are working well

6
PHENIX polarimeter
RED yell pol. ? BLUE yell pol. ?
RED blue pol. ? BLUE blue pol. ?

• We instrumented the Show Max Detector segment
  of the ZDC
• FEMs reprogrammed to send discriminator data to
  LL1 FPGA so that 8120 scaler channels can
  accumulate reasonable statistics in 5 minutes

Transverse (10371)
7
Polarization

• Polarization on the low side compared to
  projections
• Large variations during a store? Understanding
  the origin of that could be important
• Measurement controversial, but the picture seems
  pretty consistent within errors

8
Luminosity

• Im not ready to show our calibrated luminosity
  plots the CAD version is not inconsistent, but
  there are a few loose ends that still need to be
  cleaned up
• BBCLL1 cross section from vernier scan pretty
  much ok
• ß correction
• Good physics run selection
• 32 bit scaler overflow

9
Backgrounds
These counters can be blasted by 5 MHz of
particles without collisions
East Side
N5
Wall
105
ValveBox
N4
FCAL
48
MUID
Q3
Q2
Q1
D0
53..5
54
24
60
78
53
N6
Top View
8
West Side
10
Do we care about background counters?

• Only as far as they reflect background rates in
  PHENIX
• BUT they indicate beam dynamics that doesnt make
  sense to me
• Can we live with small angle backgrounds after we
  install the 10M worth of Si vertex detectors
  (Run 11)?

11
Bottom line

• There is still work to do on the big three
• Luminosityhow do we get a factor of three?
• Polarizationhow do we get 50 polarization on
  average
• Backgroundswhere do they come from, how can they
  be reduced?
• We have come a long way, but we should not stop
  without trying to run the whole program the way
  we will in the future, and we wont learn
  anything new by doing the same thing but we need
  to do repeated experiments to see how
  reproducible everything is one good store does
  not a program make

12
Teaser from Fastrak W Working Group
Leading Particle pT 33 GeV/c ecore 40 GeV