Download - V.M. Zhabitsky, N. Lebedev, E. Gorbachev (JINR), U. Blell, P. Spiller (GSI)

The Transverse Damping Systems The Transverse Damping Systems for the SIS100 & SIS300 Synchrotrons for the SIS100 & SIS300 Synchrotrons

at the Facility of Antiproton and at the Facility of Antiproton and Ion Research (FAIR at GSI)Ion Research (FAIR at GSI)

V.M. Zhabitsky, N. Lebedev, E. Gorbachev (JINR), U. Blell, P. Spiller (GSI)

5th Workshop on Scientific Cooperation between German Research Centres and

JINR

18 January 2005

JINR

27.12.2004 JINR- CERN - GSI 2

• CERN– W.Hofle, LHC ADT Project Engineer (Damper),

T.Linnecar, LHC A Project Engineer (RF), R.Louwerse, J.-F.Malo, J.Tuckmantel

• JINR– V.M.Zhabitsky, N.I.Lebedev, E.V.Gorbachev,

A.A.Fateev, A.A.Makarov, V.A.Melnikov, S.V.Rabtsoun, V.A.Bogdanov, N.V.Pilyar, V.G.Shabratov, K.P.Sychev, M.G.Pushkin, B.G.Komarov, V.I.Koryako, V.V.Kovalev + 10 pers.

JINR

The LHC Transverse Damping SystemThe LHC Transverse Damping SystemCERN – Russia - JINR

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Key Technologies in Key Technologies in Accelerator: Accelerator:

• Magnets– B, Q

• RF System– E

• Feedback Systems– N, ε

4JINR- CERN - GSI27.12.2004

FAIR at GSIFAIR at GSI• Highest beam intensities

• Brilliant beam quality

• Highest beam power

• Higher beam energies

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Bunc

h

Bunch current

Induced current

Differential current

Induced magnetic field

Vacuum chamber

Coherent Transverse Coherent Transverse OscillationOscillation

• If the bunch is displaced form the centre of the vacuum chamber it will drive a differential wall current.

• This leads to a magnetic field, which deflects the bunch.


W. HofleW. HofleCERN AB/RFCERN AB/RF

Example SPS (CNGS type beam, 1 batch, 1013 protons):• 3 ms growth rate• 0.5 ms damping time• 50 + turns relative silence at injection

injection with injection with damper offdamper off

damper being switched on 7 damper being switched on 7 ms (300 turns) after injectionms (300 turns) after injection

Transverse Feedback (“LHC Transverse Feedback (“LHC Damper”)Damper”)


SIS100 & SIS300 DampersSIS100 & SIS300 DampersTransverse Feedback System Transverse Feedback System

with a real-time digital signal processing:• damping of transverse injection

oscillations,• feedback curing transverse coupled bunch

instabilities,• excitation of transverse oscillations

for beam measurements and other applications.

General Parameters of SIS100 & SIS300Machine Circumference: 1191.96 mBeam revolution frequency: 104.1 - 251.3 kHzBeam revolution time: 9.61 - 3.98 μs Horizontal tune at injection: QH=26.9

Vertical tune at injection: QV=16.7

Energy (238U): 0.092 – 34 GeV/u

Intensity (238U73+, 238U28+): 0.09 - 0.47 - 1.1 A

JINR

27.12.2004 JINR- CERN - GSI 9

0

1

2

3

4

5

6

7

8

9

0 50 100 150 200

f(kHz)

Re

Z(M

Oh

m/m

)

1

1

2bd d

mC

mC

cmb

mmd

r

c

70

100

100.96.0

108.04.0

5

3.0

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Basic ParametersBasic Parameters

• damping of transverse injection oscillations– ∫(E┴ + β0cB┴)ds ≈ ±6.0 kV (δQ - ?)

• feedback curing transverse coupled bunch instabilities– ∫(E┴ + β0cB┴)ds ≈ ±1.3 kV

• Strength of the kicker:– ∫(E┴ + β0cB┴)ds ≈ ±9.3 kV

• Electric kicker (L=0.5m, Δ=10cm): U = ±1.86 kV

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Bandwidth and FrequenciesBandwidth and Frequencies

• fmin= min|k - Q|f0 = 0.1f0 = 10.4 kHz• fmax ≤ fb/2• fmax (for kicker) ≤ 1/4πσt = 3.2 MHz (σt=25ns)• Bunch r.m.s. spectral frequency:

<f> = 1/2πσt = 6.4 MHz• Stability of high order harmonics - ?• Sampling rate: 20MSPS• Transverse emittance growth rate:

– τ-1 = (4/3) f0 2-2(b-1) δQ2

– τ = 84 hours (f0 = 104kHz; b=12-1; δQ = 0.005)

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SIS100 & SIS300 DampersSIS100 & SIS300 DampersJINR

Power Amplifiers

Kicker

Hybrid

Central Signal Processing:

- closed orbit suppression,- phase adjust,- delay adjust.

Beam

Hybrid

Monitor Electronics

Pick-up

Gain control

Hybrid

Driver Amplifier

Monitor Electronics

+

Exitation

180o

0o

B

A

A

B

Pick-up

Driver Amplifier

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A fragment of an assembly drawing of a vertical kicker: 1 - the vacuum tank, 2 - electrodes, 3 - ceramic rings, 4 - the fixing device of the electrode module, 5 - the high voltage connection, 6 - a plate for installation of target alignment, 7 - the higher order mode connection.

• High voltage on electrodes: ±1400 V• Bandwidth: 10 – 3200 kHz• Operating vacuum: 5∙10-12 mbar

JINR KickerKicker

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• Class of operation: AB• Input amplitude: ±150 V• Output amplitude: ±1400 V• Bandwidth: 10 – 3200 kHz

JINR Power AmplifierPower Amplifier

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The experimental results confirm a possibility of realisation The experimental results confirm a possibility of realisation of amplifier on the basis of the circuit of amplifier on the basis of the circuit

with parallel control (cascode), which is considered with parallel control (cascode), which is considered as a perspective development of the system.as a perspective development of the system.

10k

1u

-135

RS2048-CJ870V

10k

-135

1u5050

RS2048-CJ

870V

out1 out2

10n

345nH 15p

90p

345nH

10n

90p

kicker

12kV

870V

12kV

870V

25 25

LHC Damper: investigationsof a cascode amplifierascode amplifier

Simulation

Test

Cla

ssic

Cas

code

(1

chan

nel)

50

25

0G

ain

, dB

Frequency, MHz

0.03 0.1 1 10 60

JINR

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Driver AmplifierDriver Amplifier

Top view View on transformers

Front view Rear view

• Class of operation: A• Input amplitude: ±1 V• Output amplitude: ±150 V• Bandwidth: 10 – 3200 kHz

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JINR Central Signal ProcessingCentral Signal Processing

• Field Programmable Gate Array(FRGA) technology

• Clock frequency: 8fRF ≤ 20MHz• Digital input signal: ±12 bit• Analog output amplitude: ±1 V• Signal processing resolution: 12 bit• Programmable delay: 3 - 10μs, ++50ns• Fine delay: 1 – 50ns, ++1ns (??)

+

-

X z( )-Nz-N

X(z) X(z X z)(1- ( ))-N

z-Mvarz-Mfix

ADC

ADC

ADC

ADC

DAC

Gating

Finedelay

Delay

Output

Controlunit

8fRF

Clock frequency

sin

cos Notch

filter

Control sequence

BP

M E

lect

ron

ics

BP

M E

lect

ron

ics

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The Transverse Damping Systems The Transverse Damping Systems for the SIS100 & SIS300 Synchrotrons for the SIS100 & SIS300 Synchrotrons

at the Facility of Antiproton and at the Facility of Antiproton and Ion Research (FAIR at GSI)Ion Research (FAIR at GSI)

Status (November 2004):Technical proposal was prepared by:– Accelerator Development Group,

Gesellschaft für Schwerionenforschung mbH Darmstadt

– Laboratory of Particle Physics of the Joint Institute for Nuclear Research

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JINR


The Damper is in the list of the systems that must operate already for first beam injection. Therefore the schedule of construction, installation and testing the Damper in the machine must be completed before November 2006.

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LHC Damper.Layout of one transverse feedback system. There are four independent systems, one per plane (H/V) and beam.

Central Signal Processing:

- closed orbit suppression,- betatron phase adjust,- delay adjust.

Beam

Monitor Electronics

Pick-up 1

Monitor Electronics

Exitation

Hybrid

Hybrid

BA A B

Pick-up 2

Hybrid

Gain control

Gain control

Gain control

+

+

+

Kicker

PowerAmplifiers

Driver Amplifier

Driver Amplifier

Kicker

PowerAmplifiers

Driver Amplifier

Driver Amplifier

0o

180o

0o

180o

Module 2Module 1

Spare Module

JINR

JINR’s obligations:• 20 deflectors,• 40 amplifiers.

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JINR


Electrostatic kickerThe design stage was successfully completed at the Laboratory of Particle Physics (JINR) and its results were accepted by CERN. Modern simulation methods based on Microsim PSpice™ and Inventor™ were used.

Wideband amplifiers

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The LHC The LHC Transverse Transverse

Damping SystemDamping System

Assembly of the amplifier and the kicker at the tests bench. LPP, October 2004.

JINR

Final amplifier design

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The LHC The LHC Transverse Transverse

Damping SystemDamping System

JINR

Radiophysical characteristics of the power amplifier:7.5 kV; 10 kHz – 10 MHz.

LPP, JINR, 10-15 December 2004.

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