Some thoughts on Tracking System for Stage 1 HPS

Simon KwanFermilab

09/28/2012

Design Considerations• Based on my understanding:

– Ready for installation in 2014– 40 layers of silicon pixel sensors (2x3 modules) each measuring

1.6cm x 2.4cm– Packaged in stacks of 5 layers ( -> 8 stacks of 5 layers each)– Resolution per plane ~ better than 50 m– Would like to avoid large dead area near pocket window (<300m) – Use as much as possible parts from CMS pixel detector (sensor,

ROC, optical links, DAQ etc)– Use ~300m long optical fibers for signal/trigger/control transmission

to/from CMS DAQ– High and potential high fluence up to 1015 p/cm2/year (please

confirm)– Detector sitting in its own box and not in secondary vacuum

• If any of the above are not valid, please sing out loud

Other important considerations• Tracking group too small; needs help in getting resources

(money, expertise, more collaborators)• Sensor R&D activities focused more on 3d sensors (Torino,

UPRJ) • Not difficult to come up with a design for the HPS Technical

Proposal but needs participation from a few strong groups to carry out the plan

• CMS Pixel upgrade now plans to have a pilot system ready for 2014 (manpower, diversion of effort ……). Possible to combine effort with FP240 Tracker???

Pixel Sensors• Current and forseen CMS pixel modules

have rather large non-active area (due to guard-ring structure) on the periphery.

• Even with tilting, we cannot get to edge requirement needed by HPS1

• So, what are the options?

Pixel Sensor Options (1)• 3d sensors with slim edge design feasible• ATLAS IBL 3d sensors require dead region around the

edge <200um. FBK is trying to get to 100um or under this year with the latest round of submission (expected back in October)

• CNM has produced large prototype 3d modules 2x8 for CMS

• A submission to FBK or CNM of 2x3 3d pixel modules using 100mm technology at a cost of 65k Euros (based on last year’s info)

• This offers synergy with the CMS HL-LHC pixel upgrade R&D

• Latest discussion with FBK: no production for about 1 year because they will move to 150mm technology

Pixel Sensor Option (2)• ATLAS IBL has pushed for a “slim-edge” design for their standard n-

on-n pixel sensors• This is done by shift the guard-rings on the p+ side inwards and

reduce the number of guard rings (overlap of the active pixel region with the guard ring region). Width of inactive edge <450mm

• The latest CMS SINTEF wafers has three slim-edge design 1x1 sensors, with inactive region varying from 250m to 450m

• CMS FPIX will proceed with a new round of submission to SINTEF using 150mm technology. Initially, thought about having 1-2 2x3 modules for HPS1 on this submission. But this leads to complication and I gave up on this.

• Instead, propose that HPS could proceed with its own submission to a less expensive vendor (CiS, TESLA) to get the slim-edge 2x3s

Note: S1, S2 and S3 have slim edges (S1 the slimmest and increasing in S2 and S3)

S1

S2

Readout Considerations• CMS Pixel upgrade in 2016 will move to a new digital readout chip, now

under development. The CMS pixel pilot system will use this new chip but the pilot system is rather small in scale.

• With this new pixel chip, the whole readout chain and the DAQ system will need to be developed.

• It is advisable for HPS1 to use the existing CMS “analog” pixel readout chip, the Analog optohybrids and the current FED

• Reason for this choice:– readout wafers and Token Bit manager already exist– Optohybrids, FEDs, DAQ etc could be the same as the current pixel system– A few years of operation experience– Cost saving

• Note: It’s possible due to schedule constraints that the pilot system developed for the Pixel Upgrade in 2014 to use the HPS1 as a possible location

Will Johns July 2011

Station Design• Pixel size is 100x150 um and if resolution required is 50um, don’t need x-

measuring and y-measuring plane• It can be mounted on a carbon fiber with excellent thermal conductivity.

All planes will be sitting on a metal base plate with cooling lines inserted.• Note: if placed inside Roman pot, the design will be very different. Have

to work closely with machine people to understand various issues such as outgassing, feedthrough, RF shielding, cooling, distance to travel (cable etc have to be flexible to allow movement)

• Cooling can be implemented (may really be needed if the fluence is as high as claimed)

• Each plane will be connected by a short flat cable to a PCB which serves a pair of planes. One TBM will be located on the PCB to orchestrate the readout.

• Power and signal/control will be provided to the ROCs through this PCB• Need to design the PCB (Station readout card) and the cable (pigtail)• Pigtail is about 60-70 cm long

Station readout• Pigtails will connect to a port card.• Two pigtails per station• Because each station is separate by a distance of 7-10m, it’l be readout

separately, • Port card or station readout card will house one Analog optohybrid ( 6

channels) and one DOH (for the ROC settings). It will also has the gatekeeper, delay25, TPLL etc. Pretty much like the current Port card for FPIX but needs a different yet simple redesign

• May consider combining the Station readout card for the Tracking station to combine with the Readout board for the Timing Detector

• From the Readout card, long optical fibers will carry signal to/from the rack nearby which will communicate with the central CMS DAQ hundreds of meters away.

• While details still have to be worked out, the proposed conceptual design should work and would need only minimal change to the DAQ and DCS software.

Guesstimate on Cost• M&S:

– sensor ~ $35k if std n-in-n slim edge– Sensor: 3d, say $80k– Bump bonding: $100k – Other electronics, cables, fibers: $15k– Power supply, VME crate, FED, FEC etc: borrow from pixel group, but set aside $40k– DCS: $10k – Mechanics: assuming no Roman pot, no cooling: a few k$. With cooling (needs

chiller, pipes etc): $15k– Total ~ $300k

• Labor:– Electrical/electronics engineer: ¾ FTE $170k Fermilab rate– Mechanical engineer: assuming no Roman pot: 0.3 FTE $80k– Technician: detector assembly: 0.4 FTE; $75k– Physicists: needs a strong team working on design, oversight, testing, DAQ,

simulation, database, DCS, Detector performance, offline. Experience of PLT shows that this is most crucial: 3 good postdocs, 2-3 grad students, 2-3 senior physicists. Needs at least three strong groups.