CDC Structure

S. Uno

KEK

2009.3.18

Endplate Design

sBelle

250mm300mm

350mm

Wire stringing

• Vertical stringing with outer cylinder.– Human can stand inside the chamber and can

touch the wire. • Inner diameter without the small cell part : ~500mm• N. Taniguchi confirmed it with a hand-made mockup.

– Stringing with tension can be done from outer layer.

• Two-way method ( Belle-CDC ) is not necessary.

Barrel PID

Backup

CDC structure

Shoji Uno (KEK)　　　

Dec-3rd, 2008

Baseline Design

Belle

sBelle

Main parameters Present Future

Radius of inner boundary (mm) 77 160Radius of outer boundary (mm) 880 1140Radius of inner most sense wire (mm) 88 172Radius of outer most sense wire (mm) 863 1120Number of layers 50 58Number of total sense wires 8400 15104Effective radius of dE/dx measurement (mm) 752 978Gas He-C2H6 He-C2H6

Diameter of sense wire (m) 30 30

1200 mm

250

mm

250

mm

Present CDC

New CDC

Wire Configuration

Small Cell Drift Chamber

Photo of small cell chamberPhoto of small cell chamber

Installation in 2003 summerJust after wire stringing

Curved Endplate• Deformation of endplate due to wire

tension was calculated at design stage of present Belle CDC (Total tension: 3.5 Ton).

Deformation(mm) 35.2 2.03 1.31

Present New

Weight

• Endplate 　– Al, Thickness : 10mm (12mm)– 110kgx2 = 220kg (264kg)

• Outer Cylinder – CRRP, Thickness : 5mm– 210kg

• Electronics Board– G10, 48ch/board– 0.3kgx315 = 95kg

Present support

Calculation of deformation and etc • Deformation of Aluminum endplate

– Thickness of endplate 　 10mm 　　 12mm• Deformation 1/t3 1 0.58

– Tension of field wire 　 120g 80g• Gravitational sag, Sense : 120m(80g), Field:300m(80g)• Total tension 4.8ton 　 　　　

• Stress calculation – Thickness of outer cylinder 　 CFRP ： mm 　– Transition structure between endplate and outer

cylinder

• Support structure• Structure for wiring jig

– Simpler one as compared with Belle-CDC

• Etc.

Wire stringing • Now, I am thinking a vertical stringing, not

horizontal. – Once, I thought the horizontal stringing

• Vertical stringing with outer cylinder.– Human can stand inside the chamber and can

touch the wire. • Inner diameter without the small cell part : ~500mm • Inner diameter of present transition cylinder :

580mm

– Stringing with tension can be done from outer layer.

• Two-way method ( Belle-CDC ) is not necessary.

Installation

• Removing and installation can be done using similar small bar in horizontal direction.

Cathode installation in vertical direction CDC installation in horizontal direction

My Personal Plan for Construction