Si Upgrade - Mechanics

1
Si Upgrade - Mechanics

• Review of Hytec study
• Mounting scheme
• Services

2
Hytec - material selection
Material for the support structure was selected
on the basis of

• High radiation length
• Low density
• High stiffness
• Availability

Materials considered Cons

• GFRP
• Beryllium
• Carbon-Carbon
• Aluminum

Availability, thermal expansion
Usually used for thermal apps.
Strength, thermal expansion, density, RL
3
material - contd
GFRP - graphite fiber - epoxy composite
which fiber? Choose one based on
cost, availability. M55J
4
strength analysis
Different structures were tried.
and analyzed for strength. Dumbbell shapes have
low bending strength. Choose
single-barrel shape.
5
build in sections
Atlas Si detector
3 sections, bolted together
Endcap frame
6
cooling
Based on the experiences with the Alice and Atlas
cooling designs

• Negative pressure system
• Water-methanol
• CFC evaporative
• CFC single-phase

And the lower total load (2.2kW), and the lower
power density (0.1-0.7 W/cm ) choose
single-phase CFC
2
Run C6F14 or C5F12 at modest overpressure
7
cooling - contd
Endcaps are cooled by tubes embedded in the
support sandwich.
Barrels are cooled with carbon-Carbon thermal
plane with Omega structure.
8
mounting scheme
TPC/HBD mounts from the top CM yoke. The Silicon
detector comes in from the bottom, much like
the MVD does now. Translate or clamshell?
9
side view - services
Power, cooling and signal services are brought
in at both ends, using the entire perimeter.
10
services - power
Power at 0.1W/cm for 1.8V technology
2
Disk r power(W) Current(A)
1 10.5 32 18 2
14.1 60 33 3 18.0
100 56 4 18.0 100
56
Total 163A
If the voltage drop over 100 is 1, then this
can be delivered via copper cable if the area is
28cm . Total for barrel 2 endcaps 190 cm
of copper.
2
2
11
services - cooling
Count tubes on various drawings.
128 tubes for 2 endcaps, bundle 9/cm 14
cm total
2
2
1/2 of one endcap
Assume a similar area for the barrel air
cooling -gt more area
12
services - fibers
Assume 1 fiber per ladder for the barrel, 2 per
ladder for the endcaps Barrel 86 cables
16.9 cm Endcaps 64/end 12.5 cm Total
for fibers 42 cm
2
2
2
13
services - how much space
Assume that services (power, air, liquid coolant,
copper and fiber are brought in on both ends,
using the entire perimeter at r20cm.
total
area dz per end From first principles
352 cm 1.4cm Current MVD 50 of
perimeter 940 cm
2.5cm Rule-of-thumb from Veljko Radeka 12 of
Silicon area (Atlas) 1444 cm
5.7cm
2
2
2
14
to be studied
For the next round, technology choices need to
be pinned down

• Power distribution - local voltage
  conversion,mass issues
• Cooling - can some be done with air?
• Keep an eye on integration

15
future
Our progress-to-funding ratio compares favorably
with industry standards
Our progress-to-manpower ratio compares favorably
with industry standard.
16
services
17
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