TOF for New-TPC experiment
1. Time-of-Flight2. Missing mass of single-K+, proton3. New-DC
Mizuki SumihamaMay, 2nd, 2008
Setup of forward
-1745 -830 -460 +1000 +3100 [mm]
~ 1 m
TPC New-DC DC1 DC2 DC3 TOF
FWD(Plastic)
Dipole
Momentum: No SVTX(SSD) , New-DCTOF : rf-TOF-wall , (Distance between target and fwd is ~1m.)
Tagger-Plastic counters for 2 nsec structure of RF signals
Standard setup : We use Start counter to solve 2 ns ambiguity of RF signals. ButNew-TPC exp. : Distance between TGT and FWD is about 1m (too long!), and TOF between TGT and FWD is not negligible and difficult to solve the 2 ns ambiguity. Use tagger plastic counters
2 nsec structure in Tagger
2 ns ambiguity can be solved by Tagger plastic counters
After time-work correctionBefore time-work correction
Missing mass spectra
MM(K+)
MM(p)
Eg < 2 GeV Eg < 2.4 GeV All
n(p+)
p0, h
E g function up to 3GeV temporary determined by Kato
Require a hit in outers No signal of p0, h
w
~5 days
Plots from the data with standard setup –Not any request at side region
MM(K+) MM(p)
n p0 h
q<25 degree
Z-vertex Target position
Vertex resolution for 2 track events is not good because of No SVTX(SSD) and small opening angles. improvement including New-DC ??
q < 14 degree
Polar angle for single track
TOF with Tag-PL and Outers
Front view of TDC, Inner and Outer•One-side readout for Inner counters, time resolution is about 800 ps by Yamamura.• Start timing is determined by RF signals and solve 2 ns ambiguity by Tagger-PL.•Stop timing is determined by Outers. Time resolution is about 200 ps by Yamamura.
New-DC
•Pitch 14 mm•YY’UU’VV’ 6 planes•U/V angle 30 degree the same as DC2 and DC3
•Accept events go through forward.•Help to determine momentum vector and vertex points in mixed magnetic field of Dipole and Solenoid .
TPC
New-DC
Installation of NDC in program for side tracking (TPCana) is by Uchida.
Forward LEPS
97mm
sense wire (Au-W) φ30μm #50×6 Layer
potential wire (Au-BeCu) φ100μm #50×6 Layer
7mm
7mm7mm
Cathode sheet (aluminized mylar) 12.5μm
V
V’
U
U’
Y
Y’
New DC DC0
xt-curveTrace back from DC1 to each planes of NDC and determine initial xt-curve.
iteration to have better xt curve.
Solve left-right ambiguity By positions of fired wiresIn Y/Y’, U/U’ and V/V’.
Require 6 hits in NDC.
Y Y’
U U’
V V’
Expected hit position - Wire position