# Presentation: 668480

## Pixel Layout Options

- E. Anderssen, D. Bintinger, M. Gilchriese
- LBNL
- and
- W. Miller
- Hytec, Inc

## Current Layout and the Issues

- At a meeting on July 8, 1998 to identify issues related to the SCT-pixel interference, the pixel group was requested to examine alternative layouts to
- see if the outer radius of the pixel structure(disk space frame) could be reduced to reduce the interference with the forward SCT.
- see if the complete pixel system could be made to fit within |z| <78 cm, which would reduce, if not eliminate, the interference and possibly simplify the interface with the beam pipe support.
- The purpose of this presentation is present preliminary results for evaluation by the pixel group.
- The region of interference is sketched below.

## Considerations(for |z|<78 cm)

- Maintain ability to get 3 detector tiles from a 4” wafer
- We assume a usable radius of 45.3mm on the wafer
- This implies that the total width of the three sensors+scribe alleys cannot exceed 64 mm
- Minimum active inner radius of disks must be > 101 mm
- This is set by tooling for B-layer insertion
- Maintain rapidity coverage to about 2.5 and at least 3 hits
- Maintain(as best we can tell) structural properties and ability to route services
- We have considered options that
- keep barrel and disk modules the same, including the existing module dimensions
- have different barrel and disk modules. This implies two different chip sizes, two different sensor layouts and two different flex hybrids/MCM-D layouts
- Electronics
- Mixing two chip sizes is considered feasible
- Having up to about 192 rows is considered feasible
- If yield is linear as one increases chip size from 160 to 192 rows, no significant impact on cost
- Need to evaluate possible impact on schedule from change to larger(or smaller) number of rows
- Flex hybrid option
- Smaller chip size for some portion of disk module is judged acceptable. Can be done.
- MCM-D option
- Wider MCM-D sensors limits options. Having same barrel and disk module seems not possible

## Current Layout Parameters

- Barrel
- 		_Radius__	__Staves__	__Modules__	__Chips__	__Channels__	_    _Active Area(m__2__)_	_Tilt_
- B-layer	4.3 cm	18	  234	 3744	1.4 x 107		0.23	-15o
- Layer 1	10.1	42	  546	 8736	3.4 x 107	 	0.54	-(11-16)o
- Layer 2	13.2	56	  728	11648	4.5 x 107	 	0.72	-(11-16)o
- Subtotal		118	1508	24128	9.3 x 107	 	1.49
- Disks
- 		Inner	Outer
- _Z(cm)_	_Radius__	__Radius__	__Modules__	__Chips__	__Channels__	_    _Active Area(m__2__)_
- 49.5	12.6	18.7	   72	1152	4.4 x 106		0.07
- 61.2	12.6	18.7	   72	1152	4.4 x 106		0.07
- 67.0	12.6	18.7	   72	1152	4.4 x 106		0.07
- 84.1	12.6	18.7	   72	1152	4.4 x 106		0.07
- 92.6	12.6	18.7	   72	1152	4.4 x 106		0.07
- Subtotal(Both Sides)	 	 720	11520	4.4 x 107	 	0.70
- GRAND TOTALS		2228	35648	1.4 x 108		2.2

## Overview of Layout Options

- TDR is the layout in the TDR
- 160 and 120
- 2x5 identical disks with 64 modules 16 chips/module. 12 chips with 160 rows, 4 chips with 120 rows
- 160, 160 and 120
- First disk as in TDR. Other disks like “160 and 120” layout.
- 192 rows(2.5 mm)
- 2x3 disks same(56 modules), and 2x2 disks same(50 modules). 2.5 mm end-of-column. 16 chips/module. All chips 192 rows. Assume barrel layout can be done with this also(to be confirmed)
- 192 rows(3.0 mm)
- 2x3 disks with 60 modules, 2x2 disks with 50 modules but with 3.0 mm end-of-column logic
- 18 chips
- This has 18 chips per module. 12 chips with 160 rows. 6 with 120. Only 4 disks. 66 modules per disk
- TDR module(z<78)
- TDR module. Same barrel and disk. 160 rows. Two different disk types:2x3 of 72 modules, 2x2 of 60 modules. This is our proposed solution for |z|<78 cm.

## Comparison of Current Layout and Proposed for |z|<78 cm

- 

## Parameters of |Z|<78 Layout

- Disks(|Z|<78)
- 		Inner	Outer
- _Z(cm)_	_Radius__	__Radius__	__Modules__	__Chips__	__Channels__	_    _Active Area(m__2__)_
- 49.5	12.6	18.7	   72	1152	4.4 x 106		0.07
- 61.2	12.6	18.7	   72	1152	4.4 x 106		0.07
- 67.0	12.6	18.7	   72	1152	4.4 x 106		0.07
- 71.8	10.5	16.5	   60	  960	3.7 x 106		0.06
- 77.0	10.5	16.5	   60	  960	3.7 x 106		0.06
- Subtotal(Both Sides)	 	 672	10752	4.1 x 107	 	0.66

- Disks(TDR)
- 		Inner	Outer
- _Z(cm)_	_Radius__	__Radius__	__Modules__	__Chips__	__Channels__	_    _Active Area(m__2__)_
- 49.5	12.6	18.7	   72	1152	4.4 x 106		0.07
- 61.2	12.6	18.7	   72	1152	4.4 x 106		0.07
- 67.0	12.6	18.7	   72	1152	4.4 x 106		0.07
- 84.1	12.6	18.7	   72	1152	4.4 x 106		0.07
- 92.6	12.6	18.7	   72	1152	4.4 x 106		0.07
- Subtotal(Both Sides)	 	 720	11520	4.4 x 107	 	0.70

## Comments/Issues on |Z|<78 Layout

- First 3 disks remain as in current layout
- Disks 4 and 5 are different, smaller
- Lifetime of inner parts of disks 4 and 5 become like Layer 1
- More radial space in region of disk 4 and 5 possible for services routing.
- Total active area is less than current area
- Deflection of support frame will increase somewhat since supports now at ends => some(small) increase in mass of outer support frame.
- Stability(vibration) of disks 4 and 5 might be worse, unless small increase in mass
- Different tooling and maybe mounts for disks 4 and 5. Increased cost of this likely offset by reduced area.

## Conclusions

- Since early July, SCT appears to have found layout that resolves interference with current layout - see http://hep.ph.liv.ac.uk/~jonest/Layout.html
- But no mechanical reasons not to implement |Z|<78 cm layout
- Lifetime decrease for part of smaller disks no worse than barrel Layer 1.
- Likely to be at least cost neutral, although different tooling sets will be required.
- Outstanding issue is pattern recognition - does closer spacing significantly degrade performance?

## Slide 10