1. Yasuhiro Sugimoto KEK Feb.4, 2008
B field and RVTX
Yasuhiro Sugimoto
KEK
Feb.4, 2008

2. Baseline design for LOI
Agreement in a phone meeting
Two configurations
5 single layers
3 doublets
Same inner and outer radii (Rout=60mm)
|cosq|=0.95 for inner three layers and outer two layers have same length as the 3ed layer
|cosq|=0.95 for inner two doubles and outer doublet has the same length as the 2nd doublet

3. Pair background simulation
Generator: CAIN
Crossing angle: 14 mrad
B-field: 3, 3.5, and 4T
Machine parameters: Nominal option in 2005
2005 parameter
Recent parameter*
Beta function at IP bx (m)
2.1e-2
2.0e-2
Beta function at IP by (m)
4.0e-4
4.0e-2
Beam size at IP sx (m)
6.55e-7
6.4e-7
Beam size at IP sy (m)
5.7e-9
Disruption parameter Dx
1.62e-1
1.7e-1
Disruption parameter Dy
1.85e+1
1.91+1
Beamstrahlung parameter Uave
0.046
0.047
Beamstrahlung power Pbeamstrahlung (W)
2.48e+5
2.4e+5
Number of beamstrahlung photons Ng
1.257
1.29
* Talk by Andrei Seryi at SiD Workshop at SLAC, Jan. 2008

4. Distribution of p.b. core

5. Design criteria Pair background core should not hit the beam pipe
Somewhat realistic assumption for the gaps and spaces (G1, G2, L1, L2)

6. Results Assumption Minimum radius G1 = 2 mm
G2 = 4 mm (core-pipe:2mm and pipe-ladder:2mm)
L1 = 5 mm
L2 = 20 mm
Minimum radius
3 T
3.5 T
4 T
R1 (mm) 12 11
10.5
Z1 (mm) 45 42 40
R2 (mm) 17 16 15
Z2 (mm) 76 72 68