Specification Ondetector 1 - PowerPoint PPT Presentation
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Title: Specification Ondetector 1
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Specification On-detector 1
- GaAs VCSEL
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Specification On-detector 2
- P-i-n photodiode
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Specification On-detector 3
- Package
- Materials
- Low Z - minimal radiation length
- Non-magnetic
- Radiation resistant
- Dimensions
- no larger than 5.55.51.6mm3
- Environmental conditions
- Operating temperature during testing -25C to
40C - Operating temperature in ATLAS -25C to 11C
- Equivalent Radiation environment (includes 50
headroom) - 300 KGy(Si)
- for Si devices 1 MeV equivalent neutrons
1015n/cm2 - for GaAs (or InGaAs) 1 MeV equivalent neutrons
9.5 1015n/cm2 - Magnetic field 2T
- Cross-talk
- When operated with VDC and DORIC4A chips the
cross-talk should not cause a BER gt 10-9 with
input optical power of 200 mW at the PIN diode of
the TTC link and 20 mA drive current for the VDC
outputs. Pseudo-random data for TTC link and
asynchronous 40 MHz clocks for VDC.
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Notes
- Device reliability (FITs) calculated to allow for
up to 1 failures over lifetime of ATLAS (108
seconds). VCSELs are only on while sending 1s
which will be for 1/4 of the LHC time assuming
50 utilisation of bandwidth and sending equal
numbers of 0s and 1s. - Operating temperature for the optics in the
barrel SCT will be in the range -250C to -150C.
The expected operating temperature for the optics
in the forward SCT is 110C - Radiation fluences have been calculated for the
worst case (Pixel B layer for 3 years _at_ 1033 cm-2
s-1 and 2 years _at_ 1034 cm-2 s-1). The particle
spectra are from the TDR calculations. The NIEL
hypothesis is assumed to scale damage to
equivalent 1 MeV neutrons. - Cross-talk specification is such as ensure no
significant BER from cross-talk with the worst
case conditions (minimum optical power into the
PIN and maximum drive current out of VDC).
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Specification On-detector 4
- Fibre
- Different requirements for different
interconnections - SCT/Pixel package to PP0/1 radiation-hard
ribbon fibre (6/12-way) - PP0/1 to PP2 radiation-hard ribbon fibre
(6/12-way) - PP2 to ROD radiation-hard ribbon cable (SCT)
- radiation-tolerant ribbon cable (Pixels)
- Radiation-tolerant fibre
- GRIN, 50/125 core/clad geometry, 12-way
ribbonized, loss (pre-irrad) lt 2.5dB/km - core composition Ge-doped
- cladding composition pure silica
- min. bend radius lt 40mm for 0.25dB loss
- Radiation tolerance loss (post- 1013
n1MeV/cm2) lt 1dB over 5m - loss (post- 1012 n1MeV/cm2) lt 1dB over 70m
- loss (post- 1kGy 60Co g) lt 1dB over 5m
- loss (post- 10Gy 60Co g) lt 1dB over 70m
- Total length required approx. 60km 12-way
ribbon - Connectors
- Multi-fibre 8-/12-way, MT or equivalent
- Low-mass, non-magnetic interconnection required
Already purchased
Still to be purchased
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Required numbers
- SCT (1 opto-package per detector module)
- On-detector 8176 (VCSELs) 4088 (p-i-ns)
- Off-detector gt4088 (VCSELs) gt8176 (p-i-ns)
- Pixels (1 opto-package per detector module)
- On-detector 4456 (VCSELs) 2228 (p-i-ns)
- Off-detector gt2228 (VCSELs) gt4456 (p-i-ns)
- Totals
- On-detector 12632 (VCSELs) 6316 (p-i-ns)
- Off-detector gt6316 (VCSELs) gt12632 (p-i-ns)
N.B. There is a percentage (6-10) of dark fibre
(unused channels) arriving at the RODs, hence
greater numbers required than at the front-end.
This is due to the geometry of the detector and
channel grouping to match the geometry.
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