Forward detector at LEPS 2

1
Forward detector at LEPS 2

• T. Nakano
• RCNP, Osaka University

August 10, 2006
2
Required acceptance and resolution

• Must be as good as the current LEPS detector.
• qLablt 20 degree
• sp/p 510-3 _at_ 1 GeV

• 10 degree lt qLab lt 20 degree
• ? 75 of the region with qLab lt 20 degree
• For measurement error, sp/p ? p.

3
Take a simple solenoid-only option
B 1T
0.5 m
1.5 m
4
We can only measure PT
P
PT
5
Simple estimation of the resolution
B 1T
L
N5
6
Some realistic cases

• P 1GeV, q 20 degree ? L0.51m , PT0.34 GeV
• 200 mm , N 5
• ? sp/p 810-3

• P 1GeV, q 10 degree ? L0.26m , PT0.17 GeV
• 200 mm , N 5
• ? sp/p 1610-3

7
How to improve?
We need a factor of 24 improvement

• Better position resolution
• Larger number of planes
• Higher magnetic field

For a factor of 2 improvement Resolution 200 mm
? 100 mm Number of plane 5 ? 32 Magnetic field
1T ? 2T
Double-side SSD sounds a good solution!