Download - Opto Working Group Summary
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Opto Working Group
SummaryF. Vasey, T. Flick
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WG meeting at TWEPP is the 2nd of the year, after a first WG meeting in spring
Topics of interest: Performance of the optical links in the various systems Plans for upgrades R&D projects
This year some of these topics were to be addressed in the optoelectronics and poster sessions on Thursday, and were not repeated during the WG.
Opto session details: https://indico.cern.ch/sessionDisplay.py?sessionId=19&confId=120853#20110928
Opto WG
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A. Current and future systems
B. Environmental tests
Agenda
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A. Current and future systems
B. Environmental tests
Agenda
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Decision: Death rate is ‘acceptable’
Regular repairs during technical stops – detectors are accessible
New batch of spares purchased from vendor no further action planned
1. LHCb StatusAs of Sept 2011, 1.8% of VCSELs died (and replaced)Silicon Tracker (IT+TT) most affected (2000 VCSELs)1 – 2 deaths per month
Ken Wyllie, CERN
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Triggerless readout: zero-suppression at front-end Use GBT + Versatile Link: ~ 11,000 data links + TTC/Slow-control
LHCb Upgrade plans
Ken Wyllie, CERN
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2. CMS Tracker
Jan Troska, CERN
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CMS Tracker
Jan
Tros
ka, C
ERN
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3. CMS E-Cal
Improvement
A.Singovski
University of
Minnesota
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Running very well, only some minor issues have been observed and are under study
Instability of some data and trigger links: loss of sync, timeout, etc. were fixed by decreasing GOH laser bias current
14 cases in 2011 (some new) Both EE and EB Bias current down to 16-22 (default = 32)
More or less uniform over the year not directly linked to LHC luminosity
In two cases: EE-7, TT3 and EB-12, TT15 decrease of laser bias current was not sufficient. The problem in both cases was fixed by the additional attenuator
CMS E-Cal
A.Singovski
University of
Minnesota
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present HCAL optolinkswork very well
For upgrade:Use GBT chipsetand commercial receivers at off-detector side and…
Eric Hazen, BU
4.
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5. AtlasTony Weidberg,
Oxford
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A. Current and future systems
B. Environmental tests
Agenda
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1. Irradiation Tests by CERN
VTx
VRxJan Troska, CERN
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2. Links at low Temperatures
Goal is to develop an optical data link system for the LBNE LArTPC.The challenge lies in the transmitting side in the LAr cryostat:- What about functionality and reliability TestingTests done using liquid nitrogen is used (LN2, 77 K) instead of liquid argon (LAr, 89 K) due to the cost.Tiankuan Liu,
SMU
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Test of different parts: fibres, connectors, laser diodes, drivers, serializer, FPGAs, resistors, capacitors by using a LN2 bath.
Tests performed
Temperature CurvePower through fibres
Laser driver @ 77K FP Laser operation I/V and L/I
Basically the componentscan work at lowtemperatures…
… but there is still a long way and Systematic studies are required to address reliability issues
Tiankuan Liu,
SMU
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Open reports about operational experience and progress Running systems either experience minor or very severe
problems. ATLAS SCT/Lar VCSEL problems seem to be under control. Thanks to very open reports, lessons are being shared.
Several systems have major upgrade plans: Medium term: LHCb and CMS-HCAL
Opto WG @ TWEPP is good to touch base. The attendance was larger than in the past years. The time was short, but sufficient to allow some discussion. Together with the spring WG mini-workshop, it offers a good and regular forum for information exchange and discussion.
Summary