# Presentation: 279774

## HFT

- Wieman
- 11/6/2004

## Outline

- Development Status
- MIMOSTAR pixel detectors
- MIMOSA5 Electronic Readout
- Ladder mechanics
- Beam pipe
- Interface issues
- External tracking requirements
- Mechanical interface
- Calibration concept

## Slide 3

## MIMOSTAR1 back from foundry

- Prototype 128X128 30 m pixels (640X640 for the full size with 4 ms frame read time)
- Final design features such as JTAG controlled internal biasing levels and multiple testing modes
- Received chip from foundry in October 04, testing to start at LEPSI/IReS

## LEPSI/IReS MIMOSA V testing at LBNL

- Developing readout skills at LBNL with a single MIMOSA V chip
- MIMOSA V is an earlier device developed at LEPSI/IReS prior to the STAR work
- Noise and leakage currents as previously measured by the Strasburg developers
- Design in progress for a multi-chip ladder using the MIMOSA V

- Lara Pierpoint
- Fabrice Retiere
- Fred Bieser
- Robin Gareus
- Howard Matis
- Leo Greiner

## Electronic/Mechanical Ladder Work – MIMOSA V

- Multi chip design
- Readout with Off ladder ADCs
- Low mass mechanical development

**Leo Greiner**

## Ladder structure and X0 budget

- Unidirectional carbon fiber skins separated by reticulated vitreous carbon (RVC) foam.
- Very stiff
- Foam separation gives large moment of inertia with little added mass
- Carbon provides large Young’s modulus with low Z
- With single end support expected to have < 10 m gravitational deflection
- Ladder mass 2.7gm (a sheet of copier paper weighs 4.7 gm)
- Carbon ladder structure 0.12% X0

- Cable = 0.10%
- 50μm Si Detector = 0.053 %
- Carrier (flat with RVC) = 0.12 %
- _Total for single ladder = 0.27%*_
- (500μm beam pipe = 0.142%)
- *RDO chip will add another 0.053% if in final design.

- More information on cable design/constraints at _[http://](http://www.lbnl.leog.org/cable_constraints.htm)__[www.lbnl.leog.org/cable_constraints.htm](http://www.lbnl.leog.org/cable_constraints.htm)_
- More information on material radiation length at http://www.lbnl.leog.org/pixel_rad_length.pdf

**Leo Greiner**

## Beam  pipe concept required for HFT, discussions started with Brush Wellman

**mm**

## Beam  pipe concept required for HFT, central region

- Beam pipe supports attach here

## Ghost Tracks – pointing accuracy – hit density

- Ghosts tracks, i.e. connecting the wrong hit to a track depends on
- Hit density on the tracking layer
- Track projection uncertainty to the layer

- Associate the closest hit to the track and the probability of a false association is:

- where

- Eugene Yamamoto’s plot

**This is not an efficiency – ghost trade off unless you set a limiting window**

## Mechanical Interface

- 3 point kinematic connection to support structure

- Two roll in rails

- Kinematic structure concept to replace earlier arm design

## Alignment and spatial calibration procedure

- Map all detector surfaces for each 4 ladder arm assembly with the vision coordinate machine
- Assemble the 6 arm assemblies and map their relative positions
- Install in STAR preserving all relative positions
- If outside tracker alignment is fully known use a few tracks to determine the 6 parameters defining position of HFT within the outer tracker
- If the outside tracker is not spatially calibrated do it with tracking through the HFT

- BarBar vertex detector in the vision coordinate measuring machine

## Kinematic assembly – constrained to repeatedly assemble to same the same location

- Allows assembly in vision coordinate machine to be the same as in the installed position** **

- Ball in cylinder pair kinematic mounts

- 6 mount points used in assembly around beam pipe

- 3 mount points for each arm