14.06.2004 LEADE, Bernd Dehning 1

Report on Beam Loss Monitors

Specification

Type of detectors

Location of detectors

Status of developments, production and tests

14.06.2004 LEADE, Bernd Dehning 2

Loss Levels and Required Accuracy

Relative loss levels

450 GeV 7 TeV

Damage to components

320/5 1000/25

Quench level 1 1

Beam dump threshold for quench prevention

0.3 0.3/0.4

Warning 0.1 0.1/0.25

Absolute precision (calibration)

< factor 2 initial < factor 5)

Relative precision for quench prevention

< 25%

Functional specification:https://edms.cern.ch/file/328146/2.0/LHC-BLM-ES-0001-20-00.pdf

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Reliability and Time Resolution

Type Area of use Criticality Time resolution

BLMC Collimation sections

yes 1 turn

BLMS Critical aperture limits or critical positions

yes 1 turn(89 us)

BLMA All along the rings (ARC, …)

no 2.5 ms (7.4.4)

BLMB Primary collimators

no 1 turnbunch-by-bunch

Definition (specs): By criticality, we mean that the system must be 100% operational to allow beam injection and that the beam is dumped if it fails.

In case of a non working monitor this monitor has to be repaired before the next injection

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Quench and Damage Levels

Detection of shower particles outside the cryostat or near the collimators to determine the coil temperature increase due to particle losses

1.E+04

1.E+05

1.E+06

1.E+07

1.E+08

1.E+09

1.E+10

1.E+11

1.E+12

1.E+13

1.E+14

1.E+15

1.E-02 1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06

duration of loss [ms]

qu

ench

lev

els

[pro

ton

/s]

Special & Collimator

Arc

Damage levels Quench level and observation range450 GeV

7 TeV

Bending magnet

Dynamic108

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Loss Detectors

Ionisation chamber few litre volume

Secondary emissionmonitor

diameter = 8.9 cm, length 60 cm, 1.5 litre

diameter = 8.9 cm, length 15 cm

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Location of Detectors (I)1. Distinguish between beams2. Observe losses due to magnet misalignments3. Observe losses due to orbit changes and emittance growth

Impact of protons in the centre of the quad. magnet

Exact longitudinal position not defined yet

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IR TAS or

BPM Q1

TRIPLET two

beam

TRIPLET abs

TAN (1+5)

or D2

(2+8)

TCL 1

TCL 2

XRP 4

locations

MSI one side

TDI one side

TCD D

one side

TCL i

one side

MSD TCD Q

TCD S

Q5 Collimator

DIS Q8

prot

DIS Q 11

prot

DIS xx

ion

DIS xx cap ion

1 SI +

SS

2 * SI

SS SI +

SS SI

SI SI SI

2 SI +

SS

2 * SI

--- SI +

SS

SI +

SS

SI +

SS

SI +

SS

2 * SI +

SS

SI +

SS

SI +

SS SI

3

xxx CI +

CS

SI SI SI

4

5 SI +

SS

2 * SI

SS SI +

SS SI SI

4 * SI

SI SI SI

6

SI +

SS

SI +

SS

SI +

SS

SI +

SS

7

xxx CI +

CS

SI SI SI

8 SI +

SS

2 * SI

--- SI +

SS

SI +

SS

SI +

SS

SI +

SS

2 * SI +

SS

SI +

SS

SI +

SS

Location of Detectors (I) (One side of IP only, has to be

multiplied by two to get the number per IP, if not indicated differently. Only one beam, if not indicated differently)

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Status of BLM’s

Current tofrequencyconverter

Multi-plexerLASER

DiodeDemulti-plexer

Thresholdcomparator

BIC (Dump)Beam PermitBeam EnergyVME Bus

Analogue Electronics Digital Electronics

Below Quad. in ARC

Ionization Chamber orSEM

At surface (SR, SX)

Ionisation chamber and SEM: final tests with proto production contracts in

preparation Installation start in 09/2005

Current to frequency converter: Prototype tests in SPS

( - 11/2004) Radiation tests at PSI (06/2004)

Transmission link (optical): GOL/GOH from CMS DIODE/TLK proto in 11/2004

Threshold comparator DAB TRIUMF BPM/BLM Proto 08/2004

Complete Proto system 12/2004

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Notation:(BLMS: Monitors in the Straight Sections, Triplett, D1, D2)

Functional specificatio

n

Engineering specification

time remarks

BLMA BLMAI 2.5x10-3 to 100s

Monitors at all quadrupole magnets, ARC (except if other

specified)

BLMB BLMB Every bunch Monitors with single bunch resolution

BLMC BLMCI + BLMCS (CI+CS)

1x10-4 to 100s

Monitors in the collimation area (I: ionisation chambers,

S: secondary emission monitors)

BLMS BLMSI (SI) 1x10-4 to 100s

Special location ionisation chamber

(low region of dynamic range)

BLMS* BLMSS (SS) 1x10-4 to 100s

Special location secondary emission monitors

(high region of dynamic range)