1Jim Thomas - LBL

The Mechanical Integration Challenge

for New Tracking Detectors in STAR

Jim Thomas07/10/2006

2Jim Thomas - LBL

The Challenge

• Design, build and install the HFT on the East end

• Keep the SSD (which is supported from East and West Ends)

• Design, build and install a new IST from the West end (?)

• Keep these detectors thin; ~1% per layer

• Keep the region of 1 to 2 units of rapidity clean and low mass

• Add new forward tracking detectors

3Jim Thomas - LBL

The SSD is a Beautiful Detector

• The SSD is thin– 1% - double sided Si

• The SSD lies at an ideal radius– 23 cm - midway between IP and IFC

• The SSD has excellent resolution – (rumor says better than design)

• The SSD is too large to be replaced– The money is better spent, elsewhere

4Jim Thomas - LBL

Existing IFC Volume

At left is cone provided by SUBATECH. The lower left photo shows the cone with SVT/SSD utility runs under outer shell. The lower right photo shows the cone with vacuum beam pipe installed. The beam pipe is trapped in the cone by its flanges and the internal pipe supports bellow.

Ralph Brown

5Jim Thomas - LBL

Existing IFC Volume

The left photo shows the SVT mounted on the support cone with SSD support rings. You must remove the SVT to get at vacuum pipe supports.

The right photo shows the SSD mounted on the cone between aluminum support rings. You must remove the SSD to get at the SVT.

Ralph Brown

6Jim Thomas - LBL

SVT Detail – beam pipe size & mounting issues …

Note

Double

Cone

7Jim Thomas - LBL

IFC Volume Options

2. Remove existing Cone, SVT, SSD, and Beam pipe as a complete unit for future heavy ion running (low risk of damage). Replace it with a new similar cone structure with SSD support plus utilities and new beam pipe. Requires fabrication of a new Beryllium/Aluminum pipe, low Z cone structure, and duplicate SSD utilities/mount (lots of time and money). Include HFT mounting interface and add to project proposal (plus Photon Converter?).

Ralph Brown

8Jim Thomas - LBL

Cross-section view of the existing STAR IFC west volume includes: Be/Al Beam Pipe, SVT, SSD, Cone, SVT/SSD Utilities (cables/hose) and RDO Boxes, FTPC, IFC Air Manifolds. You must remove the cone with SSD/SVT/Beam-pipe as a complete unit with the STAR Detector in the Assembly Building.

Existing IFC Volume

Ralph Brown

9Jim Thomas - LBL

Review of the Challenges

The challenge for the East end:

• The East end must support the HFT, SSD, and all utilities– Challenging, but can take advantage of the existing cone

The challenge for the West end:

• Support the SSD and its associated utilities and cables – with a new double layer cone

• Stay out of the 1-2 units of rapidity interval (this is difficult)– Probably requires putting utilities close to the beam pipe

• Preserve the HV integrity of the IFC– Use a graded cone shield at HV, if necessary. Probably cannot

go closer to the IFC than done by the existing cone.

10Jim Thomas - LBL

IFC Volume Options

1. Remove the SVT and its utilities from the cone structure along with RDO boxes and reinstall existing beam pipe and cone with SSD and its utilities (SVT never to return). Low cost and can be done in one summer shutdown.

Ralph Brown

11Jim Thomas - LBL