T0

1
T0 TDR

• 22nd LHCC meeting Open Session
• CERN, September 29, 2004
• W.H.Trzaska
• (for T0 collaboration)

Results and conclusions from the June 2004
comprehensive test run Milestones Cost estimate
2
Experimental set-up
3
Typical TOF spectrum obtained with a pair of
identical detectors
4
Measured time resolution
Radiatordiameter FWHMTOF SigmaPMT
30 mm 122 ps ? 140 ps 37 ps ? 42 ps
26 mm 112 ps ? 128 ps 34 ps ? 39 ps
20 mm 94 ps ? 115 ps 28 ps ? 35 ps
With shoebox (worsens resolution by ? ? 20
ps)
5
Amplitudes

• For easier comparison the areas under the peaks
  were normalized to 10000
• The amplitudes were taken with the same PMT and
  at the same HV, just the radiators were changed

6
Efficiency as function of threshold

• At very low threshold values registration
  efficiency for particles entering perpendicular
  to the front surface of the radiator is simply
  proportional to the area of that surface 100,75,
  44
• If the threshold value has to be raised (noise
  from other detectors, deterioration of detectors
  or electronics, etc.) the 20 mm radiator may
  turn out to be the best choice due to its
  excellent response function

7
T0 Efficiency in p p collisions
Radiator diameter T0 configuration T0 configuration
Radiator diameter 12 - 12 12 24
30 mm 53
20 mm 36 49
8
Backsplash spectrum (20 mm quartz)

• The efficiency for backward particles is the same
  as for forward particles but they can be
  efficiently separated by adjusting the threshold
  value

9
Backsplash in 200 PYTHIA events
T0-C
T0-A
Alla Maevskaia, INR RAS,Moscow FWD
meeting
21.09.2004
10
Conclusions I (physics)

• For all reasons except the efficiency in p-p
  collisions the 20 mm radiator is by far the
  best choice.
• excellent pulse shape
• 1/4 MIP resolution!
• The efficiency can be restored, for instance, by
  increasing the number of detectors in T0-A (next
  T0 upgrade)
• Decision expected on Nov 2004 TB

11
Conclusion II (electronics)

• We have prototype of the shoebox and of all key
  electronics (Vertex, MPD, MT, VDU, QTC)
• shoebox should work for V0 as well
• work on DCS in progress
• readout test (full chain) in 2005
• Better pulse shape (20 mm radiator) reduces the
  dynamic range
• use of off-the-shelf CFDs becomes possible
• high threshold setting possible
• stable performance

12
T0 mechanics milestones

• No concern
• T0-C prototype ready
• Integration completed
• Waiting for freezing of RB24 parameters to
  complete the design and order the production
• Production cycle 3-6 months
• Should be completed in 2005

13
T0 electronics milestones

• No major concern
• Prototypes of all dedicated T0 electronics build
  and tested
• Excellent test results
• Close collaboration with V0
• PMT, front-end (next meeting 10/04)
• trigger-specific electronics (11/04)
• HV, LV, DCS?
• T0 will use TOF readout(slightly modified)

14
Some solid dates for T0

• Nov 2004 Freezing radiator size
• Dec 2004 Electronics Design Review (joint
  with V0)
• Feb 2005 Detector module frozen mechanics
  PRR
• Sep 2005 Full chain readout test
• Dec 2005 T0 Mechanics ready
• Feb 2006 Electronics PRR
• Jun 2006 T0-C ready for installation in
  ALICE
• installation of
  electronics at CERN
• tests of the installed T0-C
• Dec 2006 T0-A ready for installation in
  ALICE
• tests of the installed T0-A

15
T0 cost estimate 318 kCHF
16
Referee question delay vs. HV
1.5 ps / V