MPSCWG 12/12/2007 1

Operational scenario of the BLM system

4/?

MPSCWG 12/12/2007 2

Addressed questions

1. Strategy for operation of the BLM system

2. Operation with < 4000 channels available?

3. Mobile BLM?

4. Tests with beam?

MPSCWG 12/12/2007 3

Summary of previous discussions

For settings generation, BLM are grouped in families

Via an expert application, a thresholds table is generated by family and stored in ORACLE database (family_info table).

This table and the monitor_info table are used to derived the MASTER table, within the Database (SQL request)

The MASTER tables (one per crate) is protected and set to a so-called ”max safe value” of the different equipment (energy and integration dependant ).

Inside the database, an APLLIED table is derived from the same family_info and monitor_info tables AND multiplying by a factor F, 0<F≤1.

Internal check within ORACLE: APPLIED table ≤ MASTER table

Present implementation, there is one F per family

MPSCWG 12/12/2007 4

Proposed values for the different tables

Element Proposed “Max safe level”

Master Table

Applied table

Maskable/ unmaskable

Number of monitors

MQ, MB Safe beam flag

Max safe value

Quench level

Maskable 2160

LSS quad Safe beam flag

Max safe value

Quench level

Unmaskable

360

DS quad Safe beam flag

Max safe value

Quench level

Unmaskable

480

TCP,TCS%, TDI, TCH, TCLP,TCLI,TCDQ,…

?? Max safe value

Damage level

Maskable ~330

MQW, MBW

Safe beam flag

Max safe value

Damage level

Maskable 60

MSI, MSD Safe beam flag

Max safe value

Damage level

Unmaskable

24+60

MBR% Safe beam flag

Max safe value

Quench level

Unmaskable

MPSCWG 12/12/2007 5

Element Damage level

Master Table

Applied table

Maskable/ unmaskable

Number of monitors

MKD, MKB Safe beam flag

Damage level

Damage level

Unmaskable

24

MBX Safe beam flag

Damage level

Quench level

Unmaskable

4

TAN,TAS ? Damage level

Damage level

Maskable 8

XRP ? Damage level

Unmaskable

9

BCM ? Damage level

Unmaskable

BPMSW ? Damage level

Maskable 8

MPSCWG 12/12/2007 6

Naming convention

Official name (i.e the layout one) : refer to the location in the cell, no indication of the beam, need to be change if one monitor in added, and BLMQI.A7L8 is attached to Q6!!

The expert name to identify the location:

BLMQI.6R7.B1E3_MQTLHBLM location:

• Q for on a quad

• E for other location

• D for the dump line

BLM type:

• I for IC

• S for SEM

Cell and sector position

Beam 1 or beam 2 observed

Transverse position:

• E for external

• I for internal

• T/B for top bottom

Position on the element:

• 1 for entrance

• 2 or 2x for inside

• 3 for exit

Observed element:

• TCT, …

• MSI

•….

MPSCWG 12/12/2007 7

Nr Description MTF query (WHERE EXPERT NAME LIKE ...) cell location No of Magnet

BLMs Type

1 Arc monitor 1 on B1 BLMQI.(12-34)%B1.%1_MQ Q12-34 IR 1/2/3/4/5/6/7/8 360 MQ

  Problem: eg. BLMQI.11L6.B1E1_MQ      

2 Arc monitor 2 on B1 BLMQI.%.B1.%2_MQ   360 MQ

    ...22 rows foreach cell?      

           

3 Arc monitor 3 on B1 BLMQI.%.B1.%3_MQ   360 MQ

4 Arc monitor 1 on B2 BLMQI.%.B2.%1_MQ   360 MQ

5 Arc monitor 2 on B2 BLMQI.%.B2.%2_MQ   360 MQ

6 Arc monitor 3 on B2 BLMQI.%.B2.%3_MQ   360 MQ

7 Cell 11 BLMQI.11%.B1.%1_MQ Q11 IR 1,2,3,4,5,6,7,8 16MQ

8   BLMQI.11%.B1.%2_MQ   16MQ

9   BLMQI.11%.B1.%3_MQ   16MQ

10   BLMQI.11%.B2.%1_MQ   16MQ

11   BLMQI.11%.B2.%2_MQ   16MQ

12   BLMQI.11%.B2.%3_MQ   16MQ

13Dispersion suppressor (BLMQI.8%(1,2,4,5,6,8)B1.%1_MQML) or Q8 Q9 Q10 IR 1/2/4/5/6/8 36MQML

    (BLMQI.9%(1,2,4,5,6,8)B1%1_MQM) or     MQM

    (BLMQI.10%(1,2,4,5,6,8)B1.%1_MQML)     MQML

  Probably: (BLMQI.8%B1.%1_MQML) or      

  Cell 9 is different... can be easier? (BLMQI.9%B1.%1_MQM) or      

    (BLMQI.10%B1.%1_MQML)      

14Dispersion suppressor BLMQI.8%(1,2,4,5,6,8)B1.%2_MQML or Q8 Q9 Q10 IR 1/2/4/5/6/8 36MQML

    BLMQI.9%(1,2,4,5,6,8)B1.%2_MQM or     MQML

    BLMQI.10%(1,2,4,5,6,8)B1.%2_MQML     MQML

15Dispersion suppressor BLMQI.(8,10)%(1,2,4,5,6,8)B1.%3_MQML or Q8 Q9 Q10 IR 1/2/4/5/6/8 36MQML

    BLMQI.9%(1,2,4,5,6,8)B1.%3_MQM      

16Dispersion suppressor BLMQI.(8,10)%(1,2,4,5,6,8)B2.%1_MQML or Q8 Q9 Q10 IR 1/2/4/5/6/8 36MQML

    BLMQI.9%(1,2,4,5,6,8)B2.%1_MQM      

17Dispersion suppressor BLMQI.(8,10)%(1,2,4,5,6,8)B2.%2_MQML or Q8 Q9 Q10 IR 1/2/4/5/6/8 36MQML

    BLMQI.9%(1,2,4,5,6,8)B2.%2_MQM      

18Dispersion suppressor BLMQI.(8,10)%(1,2,4,5,6,8)B2.%3_MQML or Q8 Q9 Q10 IR 1/2/4/5/6/8 36MQML

  IP3,7 cell 8,10: BLMQI.9%(1,2,4,5,6,8)B2.%3_MQM      

19   BLMQI.8%3.B1.%1_MQ or Q8 Q10 IR 3/7 8 MQ

    BLMQI.8%7.B1.%1_MQ or      

    BLMQI.10%3.B1.%1_MQ or      

MPSCWG 12/12/2007 8

Pending questions

Which value for the “damage level”: “Safe beam flag” for cold element?

With this strategy, MASTER table is below the damage level (factor 320 to 1000 between damage level and quench level according to the beam energy, but the same constant is used)

too much conservative?

Thresholds are defined by families:

-> There is no “general” family for region like DS, injection…-> Do we need to define OP family? How (already in LSA, in TRIM)?

It is possible to copy the MASTER Table and keep it in the flash memory of the BLETC.

-> We have to ask for this implementation?-> We can read it back and compare with DB?-> Do we push to get also the internal comparison?

MPSCWG 12/12/2007 9

Status of the software

Expert application for thresholds generation exists (ROOT scripts) and is used to fill the DB. (expert to LSA?)

Database : Work in progress, structure defined, prototype exists with some 10 families, still some discussions about history of changes

TRIM for operation : Work in progress

External tables comparison (MCS extension): to be done, but no major problem

MPSCWG 12/12/2007 10

12 running sums (40 μs to 84 s) to cover the loss duration and 32 energy levels used for filling different buffers:

logging: at 1 Hz, max loss rate in each running sums over the last second + corresponding quench levels + error and status from tests

Post-Mortem : the last 1.7 s with a 40 μs sample rate (43690 values) + the last 2 min of the logging data + thresholds and masking tables + system status info

XPOC : possible to get up to 32000 values per channel for the chosen running sum (need to be specified by LBDS)

Collimation: on request, 32 consecutive sums of 2,54 ms

Study Data: can be triggered by a timing event (to de detailed)

BLM system : signals available

MPSCWG 12/12/2007 11

Strategy : remarks/questions

The masking is done at the CIBU level: you mask all the channels connected at the same time!

-> Is it acceptable from machine protection point of view?

For the pair SEM-IC, interlock on the SEM?-> OK for SEM for collimators, but for MSD, MKD…?

The maskable/unmaskable status can be defined only at the BLM level, without reconfiguring the BIS?

What about reconfiguration of the BIS in case of disconnecting or changing the masking status at the BLM level?

MPSCWG 12/12/2007 12

2. Operation with < 4000 channels? (1/2)

Reliability of the BLM system:

G. Guaglio Ph-D thesis

Designed to be SIL 3 level : redundancy in the electronics when necessary, experience with the SPS…

acquire statistic with the existing system on SPS and LHC one as soon as available (150 days of running for the moment)

The new software part need to be included in this study

MPSCWG 12/12/2007 13

2. Operation with < 4000 channels? (2/2)

staged approach:

how much protection is needed or how much can we relax on it during commissioning with hope to gain operational efficiency?

The system need to be fully operational for phase A.5

Minimum system for each phase can/should be defined (MPSCWG)

Possibility to change status of channel via the same soft as for the Thresholds

masking helps for wrong evaluation of the threshold

possibility to change at the BLM level the maskable/unmaskable status (what about reconfiguration of the BIS?)

MPSCWG 12/12/2007 14

How many channels we can lose?

For commissioning: Assumption: The loss can be seen by another monitor so we can lose locally up to 2 out of 3 on the quad according to the margin to damage level taken (the famous C factor) for the arcs Do we have to go through the different loss patterns? (accidental case?)

What about : LSS => all needed MSI,MKD, MSD.. => ?? collimators => all needed

MPSCWG 12/12/2007 15

Mobile BLMs?Mobile BLM

Same Ionisation Chambersuse the spare channels per card : 2 in the arcs at each quad, a bit more complicated in the LSS because of more elements.electronics is commissioned as for connected channelAll the free channels/cards… will be predefined to allow their display without touching the threshold tablesNeed access to connect the extra chambersCan cover a half-cell every 3-m if 2 chambers per channelNo dump thresholds

For which use:

He leak detection: is it enough? Need some evaluation of the expected pressure dump to evaluate the signalIn the LSS?

MPSCWG 12/12/2007 16

Simulation : typical result

z (cm)

Maximum of the shower ~ 1m after impacting point in material

increase of the signal in magnet free locations

Amplitude/length of the pressure bump?

MPSCWG 12/12/2007 17

4. BLM tests

Functional test of full acquisition chain with Radioactive Source

The procedure for this test will be described in a dedicated document made in collaboration with TIS. The purpose is to create a signal on the chamber with the RA source and check its presence in the corresponding DAB card channels. Time estimation : 0.5 to 1 hour per front-end station (8 BLMs)

Provoked magnet quenchpossibility to check steady state losses quench limit with circulating beam (part of the MPS commissioning)possibility to check fast losses quench behavior if sector test

What do we lose if we cannot do the tests?

MPSCWG 12/12/2007 18

Restricted tests?

Testing only a given set of BLMs with the radioactive source?

Motivation of the quench test:Verification of the correlation between energy deposition in the coil (= quench level) and BLM signal (= thresholds)Verify or establish „real-life“ quench levelsVerify simulated BLM signal and loss patterns

=> Accurately known quench levels will increase operational efficiency!

MPSCWG 12/12/2007 19

Conclusion

GO for implementation?

Acquire statistics on the reliability of the connections and the applications during the coming dry runs

Evaluate the safety of the solution in March and if not satisfactory, close the HW switch!

Strategy to run with non-working channels? Action for the MPWG?