DT Consolidation Summary

C. Fernández Bedoya on behalf of DT Upgrade group

July 6th, 2010

But:

Improvements were realized with many ‘handmade’ patches added to boards

The UXC-USC link for half wheel is slow, 38.4Kbps

Often 485 boards lost communication with DCS (last week 2 of 10, sometimes more)Recovering requires cycling on/off the SC crate

new 485board

Integration of all patches on PCB

Maximization of USC-UXC link speed

Boards remain compatible with present hardware

Required the modification of part of DCS server software

Cost: about 15Keuro. Man power by INFN PD

MC secondary link upgrade for 2012 shutdown

Improvements in secondary link system done 2 years agohave solved the many RS485 IC ruptures on MC linkboard

Replacement of 485 boards (10) housed in SC crates

Enhancement of MC communications reliability

From Franco G.

MC SECONDARY LINKpresent system after 2008 improvements

UXC-USC optical link38.4Kbps

Sector 1/7

Sector 2/8

Sector 3/9

Sector 4/10

Sector 5/11

Sector 6/12

Primary serial link -> optical fiber

Secondary serial link -> RS485 copper chain

Half wheel

UXCUpper/bottomSC 9U crate

MCcommunication

driver485

driver485

driver485

driver485

485 chain termination& overvoltage protection

38.4Kbps

38.4Kbps

38.4Kbps

38.4Kbps

controller

RS485 board

From Franco G.

S1/S7

RS48538.4Kbps

S2/S8

S3/S9

S4/S10

S5/S11

S6/S12

RS422 link to ADLINK PMC8681(PMC board already mounted on VME SC crate controller) 230.4Kbits full duplex

Backup optical link38.4Kbps for present system compatibility(upgradable to 230.4 full duplex)

USC Interface controllers

Power from LV caen module

485 linkcontrollers1/sector

Proposed new 485 BOARD485 chain termination& overvoltage protection

From Franco G.

Consequences of LHC plan for DT:

• Reassess the robustness of our stock of spares, in particular for on detector electronics (with only 2 openings of CMS, the number of hot spares needs to be larger than planned):– Meticulous failure rate measurements during 2010

• On detector electronics:

– Not sensible redoing the Minicrates before 2020, however we are for sure short of BTIM.

– Present approach is remaking the theta trigger boards and use old boards to retrieve spare BTIMs

• UXC racks electronics:

– CAEN Low Voltage connectors: weak point in particular for A3100. • Plan is to move to A3100B (bolts) this year.• For A3050 the plan is to test lubricant in 10% of the detector

this year and see how it behaves.

– Sector Collector electronics:• Currently we need to wait until LHC stops to get UXC access in

order to fix a SC problem. A SC problem may handicap a large fraction of the detector (min a sector in trigger or readout).

• Present approach under study is to make a “simple” copper to OF conversion at SC level and move SC electronics to USC

Expectations: 3 ROBus/year , 5 TRB/year, 1 CCB Link/year

Failure rate low at present (~1/year)

C. Fernández Bedoya July 6th, 2010 5

Failure rate= 46 in 2009, 4 in 2010

From J. Nash April 2010.

PHASE 1 DT PROPOSAL (by 2015)

Long cosmic rays data taking and first pp collisions did not show any relevant weakness in the overall detector performance (resolutions, tracking capabilities, efficiencies).

But there are a few places in the electronics path that have room for improvement:1. Trigger Boards2. Sector Collector3. Drift Tubes Track Finder (Janos´s talk)

•A CMS TECHNICAL PROPOSAL is under development.•Draft version has been circulated in June.•Final version has to be available by September.


THETA TRB REPLACEMENT

MOTIVATION- BTIM mortality was high during production tests (25% spares to 3% spares).- TRB failure rate was high (1%) during commissioning phase (thermal stress?).

The rate seems to have lowered down and it needs to be totally understood during steady operation.

PROPOSAL:*BTI was produced in now obsolete ATMEL 0.5 um technology.

*We are investigating the migration to FPGA (optimizes production timescale and leaves space for possible modifications), which can also be moved to an ASIC production later if desired.

*The present plan is to replace THETA TRB with the newly produced FPGA-based ones and use the removed boards as source of spare BTIMs to be used to repair failing PHI TRBs.

*The actual implementation program will depend on the shutdown plans but we estimate that all boards of one MBX can be replaced in 6 months.

*Present proposal is to replace all boards in one full station (i.e. MB3) by 2015:

Estimated cost 360 k€ for 3 BTIs/FPGA.

2010 Production of 2 prototype boards2011 Bench tests and decision about the replacement strategy2012-2013 Mass production and test2014-2015 Installation2015 Decision about strategy in view of high luminosity operation


THETA TRB REPLACEMENT

Present situation:•ACTEL ProAsic 3 identified as best device in terms of radiation tolerance•Working prototypes of BTI algorithm inside the device have been qualified through test vectors •Studies of number of BTIs/device are on going.•At present 2 BTIs/ACTEL is feasible in terms of timing => 16 devices/TRB•3 BTIs/ACTEL done but timing not yet correct (76 MHz vs 80MHz)•A prototype board is being developed to understand possible problems.•Some concerns about higher power consumption under study

F. Montecassiano

P. Zotto

Studies performed to improve theta resolution (in new theta TRB) show that the gain (factor 2 in theta angle resolution) may not be worth the additional complications (tied to DTTF modifications).


SC to USC

MOTIVATION:

-Downtime in case of failure is high since we have to wait until LHC stops to get access to UXC.

-A SC problem may handicap a large fraction of the detector (one sector).

-Power dissipation is already marginal for CMS cooling system (lower life of electronics, plus any increase in performance cannot be accompanied by an increase of power consumption if present location remains).

-Move SC from UXC to USC to minimize impact of failures-Make a “simple” copper to OF conversion at SC level and modify input mezzanines of ROS and TSC-Low impact modifications compatible with present system and future upgrades

PROPOSAL:

New ROS:-Event processing time can be increased significantly (good for synchronous events or larger occupancy (SLHC?) than expected)-Better “normal” noise rejection capability (1 or 2 hits per ROB could be cancelled if desired)New TSC+OptoRX merged board:-Solve clock sensitivity-automatic masking if unlock-Reduce L1A latency-Improve theta resolution?

In longer term view that will simplify future upgrades, some room for improvement:


SC to USC

Make a “simple” copper to OF conversion at SC level and move SC electronics to USC

Present proposal is to make a 1 to 1 channel Cu-OF (3500 links in total)

USCUXC

ROS

TSC25 @ 240 Mbps

32 @ 480 Mbps

Equalizer Laser driver

Equalizer

… 25/ROS32/TSC

Each sector:

•Plus few components for bias setting (DAC) and monitoring.

•OF could be extracted from the back of the SC crate

1 @ 800Mbps -> 25 @ 240Mbps

6 @ 1.6Gbps -> 32 @ 480Mbps


SC to USC

-Move SC crates to USC (VME access in UXC may not be needed, compatible with future RS485 board)

-Modify input ROS and TSC mezzanines for OF reception

Fully compatible with present system

Drawbacks:

-trigger latency may be slightly increased

-Find space in USC for 10 SC crates

-Route large number of fibers (with present 48 fibers => 73 cables)


Preliminary studies:

-We have done some preliminary tests at lab with an scheme:ROB -> Cu-OF -> OF-Cu -> ROS

and first results were positive.

-We are developing a prototype board for studying different options of Cu-OF and OF-Cu conversion.

-Equalizer and VCSEL have already been tested under radiation, doubt remains on laser driver.

SC to USC

PRESENT PLAN-Fibers installation is what will need longer access time.-For the rest a scaled installation can take place in short shutdowns, also, minimal unit to replace is a SC crate

Estimated cost 800 k€ (+600k€ if ROS and TSC are totally redesigned)

1. Installation of fibers between UXC and USC (up to 3500 links distributed in 73 or 30 multi-ribbon cables). 2.a. Allocation of TSC and ROS in USC according to the space made available. 2.b. Modification of TSC and ROS input mezzanines to support optical link reception. 3.a. Redesign of ROS electronics with a new slow control interface (uTCA?) higher performance. 3.b. Redesign of TSC and Opto-RX electronics integrated in a single unit compatible with the new DTTF design.

Minicrate

ROS TSC

DTTFDDU

OptoRxUSC

UXC

Present

Minicrate

Cu-OF(RO)

Cu-OF(trg)

USC

UXC

Step 1

ROS

DTTFDDU

TSC+

OptoRx

MinicrateCu-OF(RO)

Cu-OF(trg)

USC

UXC

Step 2

DTTFDDU

TSC+

OptoRx

OF Patch panel

ROS

I think any changes we made should try to be as compatible as possible with present electronicsRebuilding full chains is very unrealistic


Not in present TP proposal

SC to USC

This is 144 fibers!

That means 30 cables for the full system (instead of 73)


-I have contacted a company in Spain (CORNING Cablesystems)-They offer optical fibers adequate to our necessities (50/125 um, data rates, etc) with Clearcurve technology (much better bending ratio with no optical loss)-144 fibers cable is still < 10 mm diameter (like our 48 fibers one)

There is also a group at CERN that can make the fibers installation, we are contacting them

Documents

DT Consolidation Summary