Vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand LHCb Vertex...

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

LHCb Vertex Detector System:Status Report

J.F.J. van den BrandSubatomic Physics Group, VUA - NIKHEF

• Review of TP design mechanics, vacuum system, cooling system.

• Requirements more cooling power,

intermediate Y positions of two halves

• Milestones

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Mechanics: “TP” design

Side flange

Bending hinges

Detector support and cooling

Bellows (22000signal wires)

Support frame

Si detector

moves by 30 mmonly two positions:open or closed !!

See LHCb 99-042/VELO

top half = bottom half

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Requirements on VD designVELO workshop in Amsterdam (April ‘00):

• Top/bottom halves should have intermediate steps (not only open/closed), with `relaxed’ overall position accuracy (0.3 mm). Only useful if we can acquire meaningful data in intermediate positions ! trigger algorithm

• Higher cooling power required (20 W/module 40 W/module) to accommodate for backup solution SCTA/velo. Should be no problem for CO2 cooling system, but is it realistic at all ?

thermal modeling needed

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Modified design

VELO Design:

• Single flange • XY table•CO2 cooling•WF suppressors•Second. vacuum•Studied

• assembly• alignment

•To do• further design• FEA

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Vacuum tank• new FEA required (probably additional ribs are needed)• flange will be on inside of LHC ring • solves lack of space issue on outside of ring• all feedthroughs on the same big flange • all cables and repeater cards on same side (present choice of feedthrough limits total number of pins to about 25,000 !!)

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Detector Modules

Number of planes: 25

Discuss

Liverpool delivers modules

40 W, 1 m cable, 50 % isolation thickness, 10 - 15 K T, radiative cooling

44 pins,440 / module

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Detector Mounting

Install Modules

3D alignment

Mount References

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Wake field Suppressor

Central cooling line

Temperature sensors (2 per station, 4 wires per measurement

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Wake field Suppressor

Welding tests: 250 m Al

FEA: Beryllium

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Foil design options (continued)

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Foil design options (continued)

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Foil design options (continued)

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

CO2 Cooling Tubes

Cooling tubes

1.1 (0.9) mm S.St.

Welding and brazing

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

CO2 Cooling Tests

Cooling system

-30o C

40 W/module

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Detector Assembly

• External reference marks• Wires fed through 7 bellows• Structure connects to frame

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Support frames• No more problems of bending: stiff, stable structure• XY-table can move down enough to allow insertion of complete detector (tilting mechanism no longer needed)• frames not any longer `in our way’ (more accessibility to critical items of VD)

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Support frames

• FEA studies ongoing• Connect to outside• Allows vacuum tests

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Support frames

• How to mount?• How to align?• Vacuum testing?• Cabling?• Rigidity?

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Support frames

• Wake field screens• 3-point support• Alignment• XY table

• 5 mm, - 25 mm• Reset switches• LVDTs• Step motors

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Support frames

•S.St. vacuum vessel•Exit foil by CERN

• RICH conflict?• Mounting RF shield?• Coating - Au, ..• z = 970 mm

• Acceptance• 300 mrad (hor.)• 250 mrad (vert.)• from IP• zero bunchlength

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Support frames

• Steel frame• Fill with sand• Dimensions

• 1630 mm• 1500 mm• 1200 mm

• Align frame within 1 - 2 mm• Fix frame

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Detector and support frame• both halves on same side• VD easier to mount and position in the tank• install complete VD at once• the two halves are no longer interchangeable

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Vacuum Tests

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Vacuum Tests

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

TP design

center frame

New design

Sideways accessibility (1)

Side wake field suppressors

Ti evaporatorNo room onthe sides !

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Sideways accessibility (2)• More access to critical WF suppressor• Much room left on one side of the tank 2ary vacuum pumps (pumping on the detector boxes is more efficient) if required, a Ti eva- porator with much more favorable design conditions

vrije Universiteit amsterdam Milan, September 25, 2000 VELO System J.F.J. van den Brand

Cooling system with mixed-phase CO2

Phase diagram CO2

1

10

100

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50

Temperature [°C]

Pre

ssur

e [b

ar]

vapor

liquidsolidgas

critical point

triple point

*