Transformers and the Linac4 Watchdog

G. Bellodi, J-L. Sanchez, B. Mikulec

with valuable input ofour BI colleagues

2

1. Low-energy Watchdog

Mainly to protect RFQ

Compare average CURRENT measurement at L4L.BCT.3113 (at RFQ exit) to a fixed threshold (e.g. 20 mA)

Charge integration only in time window between stop and start of pre-chopper (between timings Pre-chop2 and Pre-chop3)

No user or destination dependency User_Permit input to ‘Master BIC Source RF’

Watchdog Architecture

X

3

2. Linac4 and L4T watchdog

Avoid losses and protect machine from damage

Compare NUMBER OF CHARGES between L4L.BCT.4013 and L4Z.BCT.0293 for destination L4DUMP L4L.BCT.4013 and LT.BCT30 for destinations LBE, LBS and PSB

2 User_Permit inputs to ‘BIC Linac4 and Linac4 Transfer OK’

Watchdog Architecture

4

3. LT/LTB/BI and LBE/LBS watchdog

Avoid losses and protect machine from damage

Compare NUMBER OF CHARGES between L4L.BCT.1553 and BI.BCT20.S for destination PSB L4L.BCT.1553 and LBE.BCT65 for destinations LBE L4L.BCT.1553 and LBS.BCT64 for destinations LBS

2 User_Permit inputs to ‘BIC Linac4 and Linac4 Transfer OK’ (or combined with watchdog no. 2.)

Watchdog Architecture

5

4. PSB injection watchdog

Avoid losses and protect machine from damage Indication for destruction of stripping foil

Compare NUMBER OF CHARGES between BI.BCT20.S and BRi.TMD8L1 (sum over 4 rings after 100 turns)

2 User_Permit inputs to ‘BIC PSB OK(1)’

Watchdog Architecture

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Watchdog Functionality for Watchdogs 2-4

Low-loss Watchdog: No beam permit for specific USER if transmission in number of

charges is below a user-specific threshold after a programmable number of BadPulseCounts (incrementing and decrementing of this counter per user)

High-loss Watchdog: No beam permit for specific DESTINATION if transmission in

number of charges is below a set threshold (BadPulseCount hard-coded to 1)

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Transformer Specifications for WatchdogParameter Value

Sensitivity 3 V (corr. to max. intensity of 100 mA)

Accuracy 1% rms (between 10 and 100 mA)

Precision (with fixed calibration) <0.5% rmsResolution TRIC card 100 μAThermal sensitivity <300 ppm/°CHigh frequency cutoff 10 MHz (6 MHz with 100 m

cable)Low frequency cutoff 1 HzMin. pulse length (accuracy <1% in no. of charges)

50 ns

Max. pulse length (accuracy <1%)

1 ms

Max. noise <1 μA rmsMax. noise for a gate of 1 ms (lower for shorter gate)

<5E9 charges

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Conclusions

• Specifications have been discussed and agreed with BI and measurements performed with 100/200 m cables and also short pulses (F. Lenardon)

• Measured parameters fulfill all requirements

• Will there be some degradation with operational conditions in tunnel? This should be part of the commissioning.

• EDMS document (https://edms.cern.ch/document/1155020/0.2) will be updated with comments received in the approval round + this meeting and the final version submitted.