19 nov 01 – v chohan lhc beam instrumentation review1 beam intensity measurements requirements ...

19 Nov 01 – V Chohan LHC Beam Instrumentation

Review1

Beam Intensity MeasurementsBeam Intensity Measurements

RequirementsRequirements What we Intend to doWhat we Intend to do DC-BCT DC-BCT

Type, Limits, Improvements General layout Status

Fast BCTFast BCT The TT2/TT10, SPS, TI2/TI8

Fast Current Transformer Fast Beam Current Transformer

Acquisition System Fast BCTs for the LHC

A.O.B.A.O.B. Work Teams & References


Review2

Beam Intensity MeasurementsBeam Intensity MeasurementsRequirements:Requirements:

Circulating Proton Circulating Proton BeamsBeams chargescharges

NominalNominal 1.1E11/bunch1.1E11/bunch 560 mAmps560 mAmps

UltimateUltimate 1.67E11/bunch1.67E11/bunch ~ 850 mAmps~ 850 mAmps

CommissioningCommissioning 0.17E11/bunch0.17E11/bunch ~ 82 mAmps~ 82 mAmps

Single PilotSingle Pilot 5E9/bunch5E9/bunch ~ 9 ~ 9 µµAmpsAmps

Lead IonsLead Ions

[208 pb 82+][208 pb 82+]

5.58E9 /bunch5.58E9 /bunch{ 6.8E7 ions/bunch }

~ 5 mAmps~ 5 mAmps


Review3

Beam Intensity MeasurementsBeam Intensity MeasurementsWhat we Intend to do:What we Intend to do:

For the circulating nominal beams – DC-BCTFor the circulating nominal beams – DC-BCT Zero-flux device (‘Unser’ type )Zero-flux device (‘Unser’ type ) 2 independent DC-BCT systems (for redundancy) installed 2 independent DC-BCT systems (for redundancy) installed

per LHC ring in IP 4per LHC ring in IP 4

The Device Characteristics:The Device Characteristics: Temperature Dependence ~ 7 µA/’C Resolution 1.8 µA [ Res. defined as Std Dev of a series of

m’ments ] Dynamic Range 100 dB [ 9 µA to 850 mA ]

Hence Acceptable for nominal or commissioning beamsHence Acceptable for nominal or commissioning beams

Note :Note :For the single Pilot beam – DC-BCT resolution poses a For the single Pilot beam – DC-BCT resolution poses a problem ( > 10 % error ) and alternative means need to be problem ( > 10 % error ) and alternative means need to be found – { see later fast-BCT }found – { see later fast-BCT }


Review4

Development of DC-BCT at CERNDevelopment of DC-BCT at CERN

We have a certain ‘history’ and past experience with such We have a certain ‘history’ and past experience with such devices in various Accelerators & Storage Ringsdevices in various Accelerators & Storage Rings

{ post-ISR era >>> { post-ISR era >>> G.GelatoG.Gelato , , P.OdierP.Odier et al - PS Division } et al - PS Division }

ADAD:: protons: 100 µA to 6 mA (ex- AC Ring )protons: 100 µA to 6 mA (ex- AC Ring )antiprotons: 0.3 µA to 9 µAantiprotons: 0.3 µA to 9 µA (not measured by a DC-BCT)(not measured by a DC-BCT)

PSB:PSB: protons: 7 mA to 3 A protons: 7 mA to 3 A [ in each of 4 Rings ][ in each of 4 Rings ]

ions (pb): 40 µA to 2 mAions (pb): 40 µA to 2 mA

CPS: CPS: protons: 1 mA to 3 Aprotons: 1 mA to 3 Aions (pb): 5 µA to 2 mAions (pb): 5 µA to 2 mAantiprotons: 70 µA to 700 µAantiprotons: 70 µA to 700 µA

EPA:EPA: leptons: 200µA to 300 mA leptons: 200µA to 300 mA LEAR:LEAR:antiprotons: 70 µA to 4 mAantiprotons: 70 µA to 4 mA

ions (pb): 10 to 30 µAions (pb): 10 to 30 µA


Review5

Development of DC-BCT at CERNDevelopment of DC-BCT at CERN

Ongoing Work looks promising to bring down Ongoing Work looks promising to bring down the resolution of the device down to the the resolution of the device down to the order of 0.5 order of 0.5 µµA A to 1 to 1 µµAA

How?How? Reduce Noise in the Demodulator ElectronicsReduce Noise in the Demodulator Electronics Improvements in the feedback electronicsImprovements in the feedback electronics

Other issues under constant follow-up:Other issues under constant follow-up: Technical /construction : ‘Technical /construction : ‘bakeout’ [~ 150-200 ’C ] in relevant

section Performance:Performance: temperature stability gets relevant during

Beam Studies if/when multiple pilots ( n x 5E9) are stored, ‘noisy’ machine environment, magnetic elements proximity etc….


Review6

DC-BCT Typical LayoutDC-BCT Typical Layout

RF FILTER RIPPLESUPPRESSOR

OFFSETSUPPRESSOR

SIGNALDISTRIBUTION

CLOSE FRONT END

P.Odier 8/11/2001 file: LHC-dcBT_gen_layout.dsf

+ support+ magnetic shielding+ vacuum pipe+ gap (ceramic or enameled flange)+ RF by-pass

CALIBRATIONGENERATOR

MODULATOR

SYNCHRO CLOCK

INTERFACE TOTHE CONTROL SYSTEM

TIMING UNIT

TIMING PULSES RELATED TO THEACCELERATOR'S CYCLE

IBEAM

ACQUISITION

CONTROL

DISPLAY

N RANGES(N= 1TO 4)

equipment designed and built at CERN

commercial equipment

either commercial or CERN designed equipment

SPECIFICINTERFACE

MONITOR

-DEMODULATOR-AC + DC FEEDBACK-RANGES AMPLIFIER-MISCELLANEOUS


Review7

Prototype Device in LabPrototype Device in Lab

STATUS:STATUS: 1 Monitor & magnetic 1 Monitor & magnetic

shielding builtshielding built

Design of the 2 new Design of the 2 new front-end electronics front-end electronics cards is under way , i.e., cards is under way , i.e., DEMODULATOR and DEMODULATOR and FEED BACK cards. The FEED BACK cards. The noise and ripple in the noise and ripple in the electronic modules is electronic modules is expected to be reduced , expected to be reduced , hence permitting hence permitting resolution of 0.5 to 1 µAresolution of 0.5 to 1 µA

LHC dc BEAM TRANSFORMER

external diameter: 270 mminternal diametre: 114 mmlenght: 345 mm

P.Odier 11/2001 lhc3b.jpg


Review8

Fast Beam Current Transformers Fast Beam Current Transformers in the LHCin the LHC

Intention is to Install Devices permitting individual Intention is to Install Devices permitting individual bunch-to-bunch measurement in the transfer bunch-to-bunch measurement in the transfer

lines and each LHC ring.lines and each LHC ring. A. Guerrero, A. Guerrero, H. JakobH. Jakob, R. Jones, J-J Savioz, H. Schmickler , R. Jones, J-J Savioz, H. Schmickler

Characteristics:Characteristics: High Bandwidth, Low droop TransformerHigh Bandwidth, Low droop Transformer 40 MHz bunch-to-bunch acquisition rate40 MHz bunch-to-bunch acquisition rate Accuracy of 1-2 % for 5E9 protonsAccuracy of 1-2 % for 5E9 protons 30 dB Dynamic Range 30 dB Dynamic Range ( single pilot to ultimate per bunch )


Review9

The TT2/TT10, SPS, TI2/TI8The TT2/TT10, SPS, TI2/TI8Fast Current TransformerFast Current Transformer

80nm Ti Coating giving20 resistance to dampany cavity resonances


Review10


BandwidthBandwidth 500MHz

DroopDroop 0.16% per s

Dynamic RangeDynamic Range ~65dB

for LHC ~ 30 dB

Pilot = 180mVp

Ultimate = 6.7Vp }

System NoiseSystem Noise < 2mV peak-peak

SPS Housing +SPS Housing +Bergoz FBCTBergoz FBCT


Review11


Zoom

4 Batch Measurements in 4 Batch Measurements in the SPS during 2001the SPS during 2001

Bunch-to-bunch intensity Bunch-to-bunch intensity variations clearly visiblevariations clearly visible

No influence of preceding No influence of preceding bunch on signal even after bunch on signal even after 250m of cable250m of cable


Review12

Fast Beam Current TransformerFast Beam Current TransformerAcquisition SystemAcquisition System

Analogue Acquisition based on a fast integrator chipAnalogue Acquisition based on a fast integrator chip Designed by the Laboratoire de Physique Corpusculaire, Clermont-

Ferrand for use in the LHCb Preshower Detector.

Uses interleaved, 20MHz integrators and sample & hold circuitry to give 40MHz data.

Digital AcquisitionDigital Acquisition A mezzanine card will be produced, containing this chip and a 12bit,

40MHz ADC, for use with the same Data Acquisition Board (TRIUMF, Canada) developed for the LHC Beam Position System.

Bunch synchronous timing provided by the TTCbi module, part of the Timing,Trigger & Control system developed for the LHC experiments [CERN-RD12 Project Development ]


Review13

Fast BCTs for the LHC Fast BCTs for the LHC

2 independent FBCT systems (for redundancy) installed 2 independent FBCT systems (for redundancy) installed per LHC ring on either side of IP4per LHC ring on either side of IP4

LHC system will be based on current design for SPSLHC system will be based on current design for SPS

Acquisition system identical to that foreseen for the Acquisition system identical to that foreseen for the SPS and its transfer lines.SPS and its transfer lines.

Uses foreseen for the LHC system:Uses foreseen for the LHC system: Measurement of Pilot bunch intensities Determination of bunch-to-bunch intensity variations Possible input to beam dump system for finding the dump

kicker synchronisation gap Electron Cloud & Instability studies


Review14

Fast-BCTs in TT2, TT10, SPS, TI 2, TI 8Fast-BCTs in TT2, TT10, SPS, TI 2, TI 8


Review15

AcknowldgementsAcknowldgements& References& References

Work reported here is a joint effort of 2 CERN teams :Work reported here is a joint effort of 2 CERN teams : Meyrin site Meyrin site [ [ P.OdierP.Odier, J. Longo, V. Chohan ], J. Longo, V. Chohan ] Prevessin site Prevessin site [ A. Guerrero, [ A. Guerrero, H. JakobH. Jakob, R. Jones, J-J Savioz, H. Schmickler ], R. Jones, J-J Savioz, H. Schmickler ]

Some References:Some References:1.1. P.P.Odier: Prospects for Improving the performance of DC Beam Transformers,

CERN/PS 97-57 (BD) & Proc. DIPAC ’97, Frascati , Oct 1997

2. G.Gelato: Beam Current and charge measurement, Chap 7 in Beam Instrumentation CERN 001-92, 1992

3. K.Unser: Beam Current Transformer with DC to 200 MHz Range, CERN-ISR-CO/69-6, 1969

4. H.Jakob , J-J Savioz et al: The SPS Individual bunch Measurement System,CERN-SL-2001-031 BI & Proc. DIPAC 2001, Grenoble, May 2001

5. J.Lecoq, G.Bohner et al :Very Front-End Electronics for LHCb Preshower,LHCb 200-047 CALO , 6 Jun 2000

6. J.Bosser,C.Bovet etal: LHC Beam Instrumentation Conceptual Design Report, LHC Proj.Report 370, Feb 2000

19 nov 01 – v chohan lhc beam instrumentation review1 beam intensity measurements requirements ...

Documents

58e9 bunch

development of dc

bunch measurement

individual bunch

bunch intensity variations

independent dcbct systems

dodcbct type

bunch acquisition rateaccuracy