T0 status
ShinIchi Esumi
Univ. of Tsukuba
contents(1) Do we really need T0?
(2) rate estimate and statistics(3) design and installation

bbc1

bbc2

charged particle
dn/dy, dn/dη
distribution
number of hits
in a single BBC
Fritiof was foundto be similar by
Masaya.O.

BBC or trigger : 81% BBC and trigger : 42%

74%

51%

sum number ofhits in both BBCs
(BBC1>0 &BBC2>0)
Pythia : by Hiroaki.O(a)T0 trigger

BBC trigger: 29%: 81%NO bias

T0 trigger

multiplicitybias
BBC trigger

number of hit
in T0 and TOF

number of hit
in TOF withT0/BBC trigger

ratio relative tothe original TOF
hit dist. (a)If the bias is only on the multiplicity of the event,
this can be estimated with 100% NTC efficiency
and the bias can be corrected as a function of event
multiplicity.
However, if this bias depends on the particle species
or momenta, it can not be corrected even with NTC.
That kind of bias can only be known by selecting
events with or without hit on BBC, if we have T0
which has by definition no bias and provids us PID.
Without T0, we can do PID only in events with hit on
BBC. So as long as BBC does not have 100% efficiency,
we need T0 to measure PIDed spectra without bias andeven to know the bias itself.

Trigger efficiency
NTC: 100%
BBC: 80% (40%)
T0: 30%
TOF: 10%Trigger options(a) beam cross(b) a+NTC(c) a+NTC+T0(d) a+NTC.or.BBC.or.T0(1) Luminosity 1030 (cm-2sec-1) : 50kHz pp interactions(2) Trigger rate (1st level) : the same by 100% NTC trigger(3) DAQ/Data rate : 1kHz gives 90Mevents/day.
(4) 100M min. bias NTC triggered events gives
10M charged tracks in TOF.
(5) 0.5M identified protons, K/p separation up to 5GeV/c
expected power low Pt distribution(next slide)few counts in 200MeV/c bin at 5GeV/c (next slide)(6) 1 day with NTC trigger or 1/3 day with NTC+T0 trigger
without safety factor

dN/dPt (countsper 100MeV/c binfor 1M proton tracks)

exp(-mt/0.3)
power low (130GeV)
proton data (30GeV)
p-bar data (30GeV)
exp(-mt/0.17)
Pt (GeV/c)

(plan)First 1 week with transverse polarization
Next 4 weeks with longitudinal polarization(proposal)
1+1 days T0 in trigger for trans./long. polarization
1+1 weeks T0 in read-out with NTC trigger
remove T0 from IR after 2 weeks (if requested)(reason)reference for non-polarized HI beam collisions(systematically remaining long. polarization inthe trans. polarized beam)(more)
asymmetry of identified charged hadron (especiallyhigh Pt proton, anti-proton) with respect to thepolarization

Do we like to have T0 installed?

If yes, let’s continue to do it,if not, stop here.

Installation steps in 4 shifts (Susumu.S and Brendan.F)(1) attach bands to the nosecone (5hours)(2) adjust alignment of south/north bands (2 hours)(3) fix 2 common platforms for 8 PMT supports (1hour)(4) attach 4 edge PMT supports to the platform (1hour)(5) check south/north phi with 2 dummy pipes (2hour)(6) attach other PMT supports to the platform (2hour)(7) mount T0 with PCR one by one (6 hours)(8) connect all fibers of PCR to PMT (2 hours)(9) installing signal and HV cable (3hours)(10) Check signals (2hours)(a) All the steps will be exercised with dummy real
size nosecone model in Tsukuba.
(b) Carrying the parts into the IR will be tested withdummy parts especially for the band and T0.

Hiroshi.T

Hiroshi.T

Hiroshi.T

Hiroshi.T

Hiroshi.T

Hiroshi.T

Hiroshi.T