Test and start‐up procedures

Eva Barbara HolzerLHC BLM Audit, CERN June 10, 2008 1

Eva Barbara Holzer, CERN

LHC BLM Audit

CERN, June 10, 2008

Test and start‐up procedures


PhD thesis (G. Guaglio, Reliability of the Beam Loss Monitors System for the Large Hadron Collider at CERN, PhDThesis, Universit´e Clermont Ferrand II - Blaise Pascal, 2005.)

Fail safe design: “The most probable failure of the component does not generate the worst consequence (= risk to damage a magnet).”

1.Choice of reliable and radiation tolerant components environmental tests of tunnel electronics:

Temperature 15 – 50 degree Dose & single event no single event effects observed during tests,

dose corresponding to 20 years of operation

2. Redundancy and voting (when single components are not reliable enough)

3. Constant monitoring of availability and drift of readout channels (Functional Tests)

Dependability design of BLM system

Calibration

Functional testEnvironmental test

Beam energy

detector LBDSBICsurface elec.tunnel elec.magnet

Particle shower


Functional Tests PhD thesis G. Guaglio

Radioactive source test

Functional tests before installation

Barcode check (visual, serial numbers)

HV modulation test

Double optical line comparison

10 pA test

System component identity check

Beam inhibit lines tests

DetectorTunnel

electronicsSurface

electronicsCombiner

Inspection frequency:

Reception Installation and yearly maintenance Before (each) fill Parallel with beam

Current source test

Threshold table data base comparison

Functional checks – Monitoring of drifts


initiated controlled & verified

meas. device start point end point

Calibration Beam energy

detector LBDSLBISsurface elec.tunnel elec.magnet

DB

Cable identification check (sticker, visual) Cable continuity check; particularly verify if there are no conductors

swapped Test of insulation, connection and current limits (bad connection

introduces offset current The crate shall be equipped with a test card to record the measurements. Offset current with HV on shall be below 0.5 pA on all channels. MTF recording

Leakage Current {M, 5m, T, HWC} (10-BLM P6: LC(offset) w/cable&M-r)

manually manually test card in tunnel rack

monitor tunnel rack slot






DB

Tests of insulation, correct interconnections and current limits Signal cable disconnected from monitor, current source connected.

Correct channel connection checked by observing channel by channel the current signal at the test card

In case the measured currents are outside the limits the corresponding cable are changed

MTF recording

Current Source {M, 5m, T, HWC} (10-BLM P7: Signal via source w/cable)

manually manually test card in tunnel rack

cable of monitor

tunnel rack slot






DB

Before each fill Threshold table, channel parameters (e.g. electronics card number)

and channel mapping (matrix for maskable/unmaskable and connected/unconnected) are compared to the one stored in the data base

ThresholdComparator & Combine&Servey (Combiner) vs DB Comparison {F, 5m, -, HWC QUICK} (60-BLM P1: Threshold/Ch Matrix Test)

Sequencer, man. (after th. ch.)

combiner RBAC TC & combiner

ELSA DB






DB

Beam permit transmission from all threshold comparators to the last combiner card

Before each fill For maskable and un-maskable channels

TC to CS (Combiner)Transmission {F, 5m, -, HWC QUICK} (60-BLM P3: UBP Check BLETC to

BLECS)

Sequencer (timeout), Expert

combiner combiner TC last combiner






DB

Technically possible, but not yet foreseen Before each fill For maskable and un-maskable channels Beam permit transmission from last combiner card to the “controls

interlock beam user” (the interface to the BIC in the VME crate). Last combiner BLM interface to BIC Toggle of redundant lines

CS to CIBU Transmission (responsibility of BIS) {F, 5m, -, HWC

QUICK} (60-BLM P4: UBP Check BLECS to CIBU)

BIS BIS BIS last combiner BLM interface to BIC






DB

Lab test, details not finalized (see talk by Ch. Zamantzas) Tested all 16 channels, all 12 running sums and all 32 energy values

of one threshold comparator, each time a new firm ware is installed – test of firmware.

On each channels, each running sum and at each energy in the threshold comparator is brought above the abort threshold (increasing the signal and/or lowering the threshold value).

Check if firmware correctly identifies the channel above threshold.

Remove Beam Permit {F, 5m, -, HWC} (60-BLM P2: TTable User Beam Permit T)

manually manually TC TC TC






DB

The LHC energy information is sent via the “slow timing” to the CISV (VME card) and from there to the combiner (CS) (which distributes it to all TC in parallel)

Continuous check of: Transmission by CRC (cyclic redundancy check) Toggle bit to indicate updates; if timeout -> energy set to max.

value

Beam Energy Reception {F, 5m, -, HWC QUICK} (80-BLM)

continuous combiner combiner CISV combiner






DB

Check the connectivity up to the surface card before every fill The bias current is increased by 100 pA and the 1.3 second running

sum is measured and checked. Modulate the high tension with a sine wave Acquire modulated monitor signal, and check MTF recording

High Voltage Modulation {F, 1m, -, HWC QUICK} (40-BLM)

sequencer (timeout), expert

combiner combiner monitor (gas not checked)

DB






DB

Continuous check of the tunnel electronics : each minute the integrated injected current offset is checked

The bias current is increased in a control loop(possibility to correct for eventual offset in the electronics – e.g. ageing effects) so that a 10 pA offset is measured.

FPGA in CFC verifies signal levels MTF recording

10 pA Test {F, -, -, HWC CONTINOUS} (30-BLM, P2:10pA/1.3 sec run.sum)

continuos analogue tunnel el.

FPGA of CFC analogue tunnel el.

FPGA of CFC






DB

Functional test of full acquisition chain with Radioactive Source The procedure is 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 in the surface electronics and the DB.

MTF recording

Radioactive Source Test {M, 5m, -, HWC} (50-BLM)

manually manually TIMBER (DB viewer)

monitor DB






DB

The 40 us and 1.3 s running sum are measured with possible interference sources switched ON and OFF

Possible interference sources are: Collimator jaw motors Kicker magnets Injection line magnets

EMC Test {F, 2h, -, HWC} (70-BLM)

manually manually expert application

monitor DB






DB

Continuous 2 lines with CRC of transmission Decision matrix

Double Optical Line comparison

Continuous TC TC FPGA of CFC TC






DB

Continuous Check of software versions (FPGA of TC and CS) Check of electronics serial numbers

Channel / Card assignment SW check

Continuous FPGA TC & CS

TC & CS tunnel el., TC, CS

TC, CS






DB

During machine checkout For each octant BLM takes away beam permit (by toggle functionality) Measure the delay (by time stamps) between the BLM initiating and

the dump system receiving the beam dump request Reporting in MTF

Transmission Time of Beam Permit Disabling

manually manually combiner & LBDS

combiner LBDS






DB

During machine checkout Ramp dipole in 4 sectors and observe DB logging of beam energy

values Reporting in MTF

Change of Threshold Value with Beam Energy

manually manually DB, Manual dipole setting DB






DB

Pilot beam of 5109 p+ at 450 GeV Decrease thresholds (trim application) to very low value Create local bump to force a beam dump request with very low level

of losses Measure delay between signal over threshold and the beam dump :

the whole chain from the chamber to the LBDS, via the LBIS, is tested

MPS Functionality of BLM (without quenching)

manually manually BLM system simulations (magnet + monitor)

BLM system & LBDS






DB

43 bunches of 41010 p+ at 450 GeV (below damage limit) Steer the beam in the chosen magnet Check level of losses and BLM readings at the quench level Repeat for MQM, MQTL, MQ and MB If no quench occurs the threshold DB values have to be reduced Test justification and description in Chamonix XV proceedings, 2006,

Magnet Quenches with Beam (A. Koschik) A: transient losses and B: steady state losses

Provoked Quench (Transient + Steady State)

manually manually BLM system simulations (magnet + monitor)

BLM system


THE END


impact location unforeseen beam impact positionsunforeseen aperture locations

enthalpy (Cu, NiTi) (fast) erroneous geometrymodel errors

heat conductivity (slow) erroneous geometrymodel errors

coil energy deposition erroneous geometry (peak, average)Geant, FLUKA errors

detector energy deposition (slow / fast) erroneous geometryerroneous Geant

detector signal (slow, fast) steady high loss rate (saturation)fast high loss rate (saturation)steady low loss rate (leakage current)

transmission (Cu) erroneous cablinginterruptionsmall signalslarge signals

digitalisation (slow) small values (ADC)large values (CFC)

digitalisation (fast) large values (CFC)

transmission (opt.) erroneous cablinginterruptiondata integrity

threshold comparison (fast, slow) reception of data erroneousFPGA comparison small-large valueserroneous threshold values

BLM beam permit, (un)mask able, A/B (two redundant lines)matrix wronglink blocked TC to Combiner

transmission CIBU, mask able, A/B erroneous cablingtransmission CIBU, un-mask able, A/B interruption

ground connection

survey of internal voltages and currents HV, CFC, TC, VME crate, HV crate

EMC noise

energy reception beam energy

implemented? Defined? (jan2008) not impl.? not defined part. impl. implemented? not defined impl.test is controlled and verified by manual manual manual combiner combiner analogue FE FPGA combiner manual

measurement devicetest card in tunnel rack?

test card in tunnel rack?

expert application?

combiner combiner analogue FE crate CPU? combinerexpert aplication

combiner & FPGA

test starting point in the BLM signal chain monitorcable of monitor

monitormonitor (gas not checked)

analogue FE analogue FEoptical transmitter

analogue FE FPGA FPGA FPGA last combiner monitorSMP (safe machine oarameters)

test end point in the BLM signal chain mini-rack slot mini-rack slot DB? DB FPGA DB? opt. receiver FPGA DB? FPGA last combinerBLM interface to BIC

DB? combiner

test initiated by manually manually manuallySequencer Expert

Sequencer Expert

continous continous continousSequencer, manually after th. Change

Sequencer, Expert

BIS manually continous

Before each start-up and after change in installation Before each fill Parallel with beam


The BIS (Beam Interlock System) Architecture

Three ring-type systems:• LHC Beam 1 & Beam 2• SPS

Four tree-type systems:• LHC injection (Beam 1 & 2)• SPS extraction (BA4 & BA6)

User Permit A

User Permit B

Beam Permit Info

Test

Monitor

<1200m

USERINTERFACE

ELECTRONICS

BEAMINTERLOCK

CONTROLLERELECTRONICS

true false

‘DC’ Signals

Encoded Data Frames

User Permit A

User Permit B

Beam Permit Info

USERSYSTEM

ELECTRONICS

<4m

Permit Loop Beam-1 Anti-Clockwise

Permit Loop Beam-1 Clockwise

Permit Loop Beam-2 Clockwise

Permit Loop Beam-2 Anti-Clockwise

To/FromNext/

PreviousBICs

<6000mCurrent Loops RS485 Channels Fibre Optics

1 2 3

CIBU


Calibration / Threshold determination

BLM signal

Number of locally lost beam particles

Deposited energy in the machine component

Fraction of quench and damage level of the machine component

Proton loss locations

Hadronic showers

Chamber response Hadronic showers (energy deposition in magnet)

Quench and damage levels as function of loss duration (heat flow in magnet)Threshold values

Machine component Loss location Detector position Beam energy Loss duration

Test and start‐up procedures

Documents

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