Location of BLMs in the LHC

E.B. HolzerMPWG, Location of BLMs in the LHC April 23, 2004 1

Location of BLMs in the LHC

• The BLM system (short overview)• Data from the BLM system• Installation in the arcs• Installation in the insertion regions


Purpose of the BLM system

• Machine protection against damage of equipment and magnet quenches

• Setup of the collimators

• Localization of beam losses and help in identification of loss mechanism

• Machine setup and studies


The BLM families

Position Description Number of detectors

BLMA Quadrupoles along the ring (6 per quadrupole), ionization chambers attached outside of cryostat, time resolution 2.5ms.

~3000

BLMS Critical aperture limits or positions, ionization chambers, time resolutions 1 turn: BLMSI (ion. ch.)

~400

BLMS* Critical positions for injection losses, extended dynamic range: BLMSI (ion. ch.) + BLMSS (SEM), time resolution 1 turn.

~100

BLMC Collimation sections, BLMCI (ion. ch.) + BLMCS (SEM), time resolution 1 turn, used to set up the collimators.

~110

BLMB Primary collimators, not part of baseline scenario, for beam studies, bunch-by-bunch resolution.

10


Estimation of fluency through the BLMs

min max

BLMA

BLMS

7 TeV 5 103 8 108 mips / cm2 s

450 GeV 102 1010 mips / cm2 s

BLMC 7 TeV 1.5 104 6.4 1013 mips / cm2 s

450 GeV 2 105 1016 mips / cm2 s


Signals from the BLM system

• Dump signal• Logging• Post mortem


Logging Data Arrangement

These data have to be read with a rate of a second in order to be stored in a database as well as to give a graphical representation

for the control room.

•The card’s Threshold table. (~ 22 KBytes)•The measured & calculated data. (< 2 KBytes)•The used Threshold values. (< 1 KBytes)•The max of read values ( 100 Bytes)•Additional info (card ID, status, errors) ( ~16 Bytes)

Total from each card ~ 28KB per minute

From C. Zamantzas, not jet implemented – under discussion.

CID (card ID)STATUS

CRC errors(~16 Bytes)

Measured data(~2 KBytes)

Threshold data(~960 Bytes)

Maximum values(~ 100 Bytes)

Words

1

2

3

4

5

.

516.

517

.

.

.

576

.

.

.

600

1 2 3 … 16 … 32

Bits


How a Control Room Representation could look

The Control Room will be able to issue the Warning level alerts from logging data and have a graphical representation:

0

0.2

0.4

0.6

0.8

1

1.2

Me

as

ure

d/T

hre

sh

old

DumpLevel

WarningLevel

Max

The 12 values measured for each detector have to be normalised by their corresponding threshold value; from those 12 the maximum value is displayed.

From C. Zamantzas, not implemented.


Post Mortem Data Recording

• Two circular buffers• 2000 turns of both signals received• Integrals of 10 ms (data needed for further analysis)

• Double the above system and toggle between them using the stop PM recording trigger

• Never stop recording (i.e. avoid start input)• Test of PM will be possible anytime• Accidental/error-triggering proof

• PM freeze from TTCrx through the backplane.• Time-Stamp appended later by crate CPU.

• At PM freeze the CPU records the time and later when it reads the PM Data appends it to them.

• Calculations: – 1000 turns 2000 acquisitions * ~250 bits frameword 60 KB/signal * 2 signals/card = 120 KB /card 120KB/card * 18 cards/crate = 2.1 MB /crate

From C. Zamantzas, not jet implemented – under discussion.


BLM locations in the arcs – transverse plane

• BLMs installed outside of the cryostat, maximal signal in horizontal plane (least amount of material).

• Number of shower particles underneath the cryostat: ~10 times less than in horizontal plane.

phi

z (cm)

phi

phimean = 10.59º

region of shower maximum

Phi-distribution of particles exiting the vacuum-vessel

Phi (angle in transverse plane) distribution of particles exiting the vacuum vessel (GEANT simulation)


BLM locations in the arcs – longitudinal

• 3 loss locations simulated: shower development through the cryostat, GEANT 3.

• The positions of the BLMs are chosen to:– reduce difference between inside and outside loss– minimize crosstalk– distributed loss to resemble point loss– reduce difference with and without MDCO.

BLM positionLoss location


First simulation results on longitudinal proton loss distribution

Tracking of tertiary halo particles, E.B. Holzer and V. Kain (end of 2003), complete aperture model (DS and arc right of IR7), (halo particles simulated by R. Assmann), ideal alignment.

Quadrupoles

-0.00005

0

0.00005

0.0001

0.00015

0.0002

0.00025

0.0003

Longitudinal losses strongly peaked at the beginning of the quadrupoles (dipoles not shown).


BLM installation in the insertion regions

• Collimation regions• ATLAS and CMS• Injection (ALICE and LHC B)• IR4 and IR6

Table with the BLMS (“SI” – ionization chamber, and “SS” – SEM) and BLMC (“CI” and “CS”) locations per insertion region.

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.

Sketch with detector locations and number of monitors (G. Ferioli):

BLMA (blue), BLMC (red), BLMS (black) … number of monitors per location


Collimation regions

IP 311C

1Q4Q8Q11 Q11Q8

UJ 33

1 1 1 1 1C

11 1 1 1 1

SR 3

66 6 66 6 6 6

11 1 1 1 1 1 111 1 1 1 1

6 666C C C C C C C C C C C C Q4

66 6 6

IP 7Q4Q8Q11 Q11Q8

SR 7RR 73 RR 77

Q5Q611 1 1 1 11 1 1 1 1 1 1 1 1 1 1 111

Q6Q7 Q76 6 6 6 6 6 6 6666666

11 1 1 1 11 1 1 1 1 1 1 1 1 1 1 111

11 1 1 1 11 1 1 1 1 1 1 1 1 1 1 111 66

11 1 1 1 11 1 1 1 1 1 1 1 1 1 1 111

C C C C C C C C C C C C C C CC CCCC Q5Q4C C C C C C C C C C C C C C CC CCCC

IR Collimator DISQ8prot

DISQ11prot

DISxxion

3 xxxCI + CS

SI SI SI

7 xxxCI + CS

SI SI SI

Ionization chamber

SEM

BLMA (blue), BLMC (red), BLMS (black) … number of monitors per location

Number of BLMS and BLMC locations

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


IR1 (ATLAS) and IR5 (CMS)

IR TAS TRIPLETtwo beam

TRIPLET abs

TAN TCL1 TCL2 XRP4

locations

DISQ8prot

DISQ11prot

DISxx

capion

1 SI+SS 2*SI SS SI+SS SI SI SI SI SI

5 SI+SS 2*SI SS SI+SS SI SI 4*SI SI SI SI

IP 1TAN

6 6 11 11TAS TANTAS

2TCL

RR 13

Q4TCLQ52 2

TCL2

TCLQ4 Q5

6 6

Q8Q11 Q1Q2Q3 Q3Q2Q1 Q11Q8

RR 17SR 1

6 66 6 6 6 6 6 6 6

1 11 1

6 6666 666TRI TRI

1 1

IP 52

TCLQ4TCLQ5

2 2TCL

2TCLQ4 Q5Q8Q11 Q11Q8

RR 53 RR 57

6 6

Q3Q2Q1

SR 5

XRP

2

XRP

2 6XRP

2XRP

2XRP

26 6 6 6 6 6 6 6 6666 6 661TAS

1

1TAN

1

TAN

6 6 11

TASQ1Q2Q3

6

1 1

TRIXRP

2

TRI

6

1 1


Injection – IR2 (ALICE) and IR8 (LHC B)

IR BPM Q1

TRIPLETtwo

beam

D2 MSIone side

TDIone side

TCDDone side

TCLIone side

DISQ8prot

DISQ11prot

DISxx

capion

2 SI+SS 2*SI SI+SS SI+SS SI+SS SI+SS 2* SI+SS SI+SS SI+SS SI

8 SI+SS 2*SI SI+SS SI+SS SI+SS SI+SS 2* SI+SS SI+SS SI+SS

IP 26 3 3

TCDDTDIMSI

6 6

Q4

1

D2

2

TCLQ4 Q5

2

TCLQ6Q8Q11 Q1Q2Q3 Q11Q8

UA23 UA27 ESR 2

66 6 6 6 6 6 6 6 6 6666 6661 11D2

6 6Q3Q2Q1

6

1 12

BPM BPM

111 1

IP 26 3 3

TCDDTDIMSI

6 6

Q4

1

D2

2

TCLQ4 Q5

2

TCLQ6Q8Q11 Q1Q2Q3 Q11Q8

UA23 UA27 ESR 2

66 6 6 6 6 6 6 6 6 6666 6661 11D2

6 6Q3Q2Q1

6

1 12

BPM BPM

111 1

IP 8 3 3 6TCDD TDI MSIQ4Q4

2

TCL Q5

2

TCL Q6Q8Q11 Q11Q8

UA 83 UA 87

SR 8

6 6 6 6 6666 6 6666 66Q5

6 61

D2 Q1Q2Q3

6 1 11

D2

6 6

Q3Q2Q1

6

BPM BPM6

1 1 211 11

IP 8 3 3 6TCDD TDI MSIQ4Q4

2

TCL Q5

2

TCL Q6Q8Q11 Q11Q8

UA 83 UA 87

SR 8

6 6 6 6 6666 6 6666 66Q5

6 61

D2 Q1Q2Q3

6 1 11

D2

6 6

Q3Q2Q1

6

BPM BPM6

1 1 211 11


IR4 (RF, instrumentation) and IR6 (extraction)

IR MSD TCDQ TCDS Q5

4 to be defined

6 SI+SS SI+SS SI+SS SI+SS

IP 64 4

MSD

6

TCDSTCDQ

6 4

MSD

4

TCDS TCDQQ4 Q4Q8Q11 Q11Q8

UA 63 UA 67SR 6

6 6 6 6 6 6 6 66666

Q5 Q5

2 2 2 22222

IP 4Q5 Q11Q8

UA 43 UA 47 SX 4

6 6 6 6 6 6666 66Q5

6 66


Your input needed

– BLM locations in IR3, IR7 and IR4– Comments on the locations in IR1, IR2, IR5

and IR6

Location of BLMs in the LHC

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