A. Castañeda 07 th September 2009

Generators and DetectorsPermit Loop / CIBG / CIBO

0v0

alejandro.castaneda.serra@cern.ch

Summary

● Brief Summary about Permit Loops

● Beam Permit Loop Frequency Generator (CIBG)

● Optical Transceiver (CIBO)

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alejandro.castaneda.serra@cern.ch

BRIEF SUMMARY ABOUT BEAM PERMIT LOOPS

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Permit Loops

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alejandro.castaneda.serra@cern.ch

Permit Loops

● A single generator is used in the whole loop● The frequency is not regenerated at any point ● Avoid failures that could force the permit loop to be maintained

regardless of the actual state of the USER_PERMIT signals.● Frequencies chosen 8 – 10 MHZ

– Allow rapid response.– Not harmonics with any known frequency in any CERN accelerator.

● In the case of the LHC:– One loop anticlockwise (A) and One loop clockwise (B)

– A : 9.375 MHz / B: 8.375– The signal is repeated 18 times and travels aprox 45 kms.

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alejandro.castaneda.serra@cern.ch

Beam Permit Loop General Layout

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B

A

● CIBG is responsible for the generation of the BEAM_PERMIT freq.● Any USER_SYSTEM can break the frequency loop through a

USER_PERMIT triggered to the corresponding Beam Interlock Controller.

● If the frequency appears at the end BEAM_PERMIT TRUE● In the LHC Reaction time ~ 120 μ s

alejandro.castaneda.serra@cern.ch

CIBG(Beam Permit Loop Frequency Generator card)

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alejandro.castaneda.serra@cern.ch

CIBG – I/O

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CIBG – Hardware Implementation

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CPLD GENERATOR CIRCUITS

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TxRx

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CIBG – Frequency characteristics

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● Output frequency accuracy:

Test freq

alejandro.castaneda.serra@cern.ch

CIBG – Frequency characteristics

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● Input frequency accuracy:– Slow detector (Nominally A: 9.375 MHz / B: 8.375 MHz)

- It activates when the integrity of the optical link degrades over time.- It counts the number of edges sent in several hundred microseconds.- Slow detect: ± 5% error / Measures takes 100 ms.- And compares to the following boundaries.

alejandro.castaneda.serra@cern.ch

CIBG – Frequency characteristics

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● Input frequency accuracy:– Fast detector (Nominally A: 9.375 MHz / B: 8.375 MHz)

– It observes the link for a few 100ths of ns.– Detects the change in link state due to a real request for Beam Dump– Fast detect : ± 10% error / Measures takes 3-4 μs.

alejandro.castaneda.serra@cern.ch

CIBG – Additional Information

● You can find all detailed schematics, pcb layouts and electrical characteristics about the CIBO in sections #12 and #16 of the folder provided .

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alejandro.castaneda.serra@cern.ch

CIBO(Optical Transceiver)

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alejandro.castaneda.serra@cern.chCERN, the LHC and Machine Protection 16 of 19

CIBO

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CIBO – Block diagram

TTL

-36 to -39 dBm Sensitivity

No Effect Maintenance False Dump Blind Failure

1.96833 x 10-7 0 8.29872 x 10-7 3.428 x 10-9

CIBO P(Fail) per Hour

-15 to -25 dBm Output

1310 nm Singlemode

alejandro.castaneda.serra@cern.ch

CIBO – Additional Information

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● You can find all detailed schematics, pcb layouts and electrical characteristics about the CIBO in sections #20 of the folder provided.

alejandro.castaneda.serra@cern.chCERN, the LHC and Machine Protection 19 of 19

FIN