Beam Line Tuners
description
Transcript of Beam Line Tuners
f
Beam Line Tuners
Vic Scarpine
Instrumentation
DoE Review
Oct 28-31, 2002
October 28-31, 2002 DoE Review - Instrumentation - BLT 2
f Introduction
• Primary function of a Beam Line Tuner (BLT) is to measure turn-by-turn transverse beam positions during transfers between machines at injection to improve closing– Required in Tevatron, Main injector and Recycler
– Can measure betatron oscillations, fractional tune, coupling, phase, synchrotron oscillations, chromaticities, etc
• Focus has been on betatron measurements for improved closing
– Feed-forward correction system
• BLT is a key component for reducing transverse emittances and increase luminosity
October 28-31, 2002 DoE Review - Instrumentation - BLT 3
f Basic BLT System
K * (A - B) /(A + B)
Beam
A
B
StriplinePickup Position
PhaseAmplitude
Tuneetc
Signal Processing
Analysis
October 28-31, 2002 DoE Review - Instrumentation - BLT 4
f Striplines and Fanout
TeV Stripline Parameters:– ~ 30 dB directionality
– 1 meter long (< 1/4 )
– D = 83 mm
– 0.65 dB/mm Sensitivity
MI and Recycler Stripline Parameters:– Unidirectional
– 1.4 meter long (1/4 )
– D = 110 mm
– 0.50 dB/mm Sensitivity
~300 ns, 7/8" Heliax
~300 ns, 7/8" Heliax
~300 ns, 7/8" Heliax
~300 ns, 7/8" Heliax
Ver
tical
Hor
izon
tal
VerticalStripline
HorizontalStripline
Pro
tons
Upstream A
Downstream A
Downstream B
Upstream B
PassiveComponent
Fanout
Upstream A
Upstream B
Downstream A
Downstream B
Proton A+B
Proton A-B
Pbar A-B
Pbar A+B
Proton A
Proton B
Pbar A
Pbar B
Proton A+B
Proton A-B
Pbar A-B
Pbar A+B
Proton A
Proton B
Pbar A
Pbar B
October 28-31, 2002 DoE Review - Instrumentation - BLT 5
f
Operational Systems
October 28-31, 2002 DoE Review - Instrumentation - BLT 6
f Tevatron BLT
• For transfers from Main Injector to Tevatron• Requirements (in order of importance – V. Lebedev):
1. Measure initial injection oscillations for every proton and pbar bunch – first 50 turns with <50 m resolution
2. Measure tunes, coupling and chromaticities for every bunch– > ~1000 turns
3. Monitor beam position before quench– ~ last 500 turns saving beam waveforms
• Beam formats:– Pbar:
• Four 53 MHz bunches separated by 392 ns at 150 GeV
– Protons: • Single 53 MHz bunch at 150 GeV
October 28-31, 2002 DoE Review - Instrumentation - BLT 7
f Tevatron Scope BLT
• In Operations• Use Tektronix TDS7104 as fast
waveform digitizer– 2.5 GSample/sec/channel– Segmented memory– Embedded Celeron PC
• Samples proton bunch or four pbar bunches per transfer
• Signal processing analysis on waveform in Scope PC
• Decimate data to single position per bunch– Pbars – 64 turns– Protons – 256 turns
GPIB
ACNET
Scope PC
Tektronix TDS7104
MUX
Horz A+B
Horz A-B
Vert A-B
Vert A+B
CH 1
CH 4
CH 3
CH 2
Horz A+B
Horz A-B
Vert A+B
Vert A-B
Horz A+B
Horz A-B
Vert A+B
Vert A-B
PROTONS
PBARS
October 28-31, 2002 DoE Review - Instrumentation - BLT 8
f Tevatron Scope BLT Results
First Pbar Transfer Sixth Pbar Transfer
1 12 3 4 2 3 4
4 pbar bunches per transfer; 64 turns per bunch; closing on second bunch
October 28-31, 2002 DoE Review - Instrumentation - BLT 9
f Tevatron Scope BLT
• Position calculation:X = K * (A – B) / (A + B)
Resolution: ~ 140 m
• Calculate oscillation phase and amplitude from first 16 turns
• Correct injection magnets for next transfer for amplitudes > 0.25 mm
Betatron phase and amplitude for all 36 pbar bunches
October 28-31, 2002 DoE Review - Instrumentation - BLT 10
f Tevatron Scope BLT Status
• Tektronix scope system in operations– Limited by slow internal data transfer
• ~20 seconds for 64 turns for pbars
• Improvements– New scopes have increased memory – two scopes just arrived
• Allows for ~800 turns for pbars, ~2000 turns for protons
– Upgrade scope software to improve internal data transfer• Increase acquisition speed by ~ x10
– Modifying position algorithm to improve resolution• ~ 30 to 50 m
– Integrate improvements over next few weeks
October 28-31, 2002 DoE Review - Instrumentation - BLT 11
f Main Injector BLT
Requirements:– Measure position for first 1024 turns for all pbar bunches at
injection from either Accumulator or Recycler• “Hot” pbars from Tevatron in future
Beam Formats:1. Accumulator to Main Injector – Four batches of 7 to 13 bunches
of 53 MHz at 8 GeV
2. Recycler to Main Injector – Four bunches at 2.5 MHz at 8 GeV
3. Tevatron to Main Injector – 36 single bunches at 53 MHz at 150 GeV (Hot pbars)
October 28-31, 2002 DoE Review - Instrumentation - BLT 12
f Main Injector BLT in Operations
• Using older AM/PM modules (see J. Crisp talk on BPMs)– Originally designed for eighty-
four 53 MHz bunches– Lower efficiency for 7 bunches– Less resolution– Won’t work for 2.5 MHz
• Digitize at 53 MHz• LabView controls acquisition
and analysis• Output 1024 vertical and
horizontal positions plus fractional tunes and betatron phase and amplitude to ACNET
RF
Beam Sync
PC
Gate
Controller
UCD
AM/PMModule
A
B
Position
Intensity
AM/PMModule
A
B
Position
Intensity
Dig
LabViewACNET
Horz
Vert
VXI
October 28-31, 2002 DoE Review - Instrumentation - BLT 13
f Main Injector BLT Results
•Phase and amplitude for 9 transfers•Correct for amplitude > 0.5 mm
•Positions and tunes for first 1024 turns•Correct on second bunch in transfer
October 28-31, 2002 DoE Review - Instrumentation - BLT 14
f Main Injector BLT Status
• Present system based on old AM/PM modules– Adequate for closing but needs updated to more responsive system
• System can not measure 2.5 MHz beam from Recycler
Plan:
• Installing Digital Receiver system for 2.5 MHz beam– Installation occurring now
• Need to replace present 53 MHz system– Decision to be made on choice of Digital Receiver system or
Scope system
October 28-31, 2002 DoE Review - Instrumentation - BLT 15
f Recycler BLT
ACNET
Horz
Vert
RFAmpA 5 MHz
LP
RFAmpB 5 MHz
LP
RFAmpA 5 MHz
LP
RFAmpB 5 MHz
LP
VME
Power
PC
RFTrigger
DR
DR = Digital Receiver
• Requirements:– Measure position for first 1024 turns
for all bunches at injection from Main Injector to Recycler
• Waveforms:– Four 2.5 MHz pbar bunches at 8 GeV
• System based on Digital Receiver technology– Uses Echotek digital receiver
• Just into Operations
October 28-31, 2002 DoE Review - Instrumentation - BLT 16
f Digital Receiver Options
Fast ADC
Digital Mixer(down conversion)
Filters andDecimation
Amplitude and Phase
Single
Channel
A, B or A-B, A+B • Hardware Option (see J. Crisp talk on BPMs)– 8 channel EchoTek card (VME64)
– 65 MHz ADC, 14 bits
– Hardware digital mixer, filters and decimation
• Software Option– 8 channel Struck digitizer (VXI)
– 100 MHz ADC, 12 bits
– Software digital mixer
– Correlation algorithm to measure channel amplitude
October 28-31, 2002 DoE Review - Instrumentation - BLT 17
f Recycler BLT
Positions and tunes for 1024 turns
October 28-31, 2002 DoE Review - Instrumentation - BLT 18
f Recycler BLT Status
• System in operations for about one week
• Closing routinely to < 0.3 mm
• No changes planned to system
October 28-31, 2002 DoE Review - Instrumentation - BLT 19
f
Systems in Development
October 28-31, 2002 DoE Review - Instrumentation - BLT 20
f TeV Scope BLT Phase Detector
• Measures phase of four pbar bunches relative to RF using Tektronix 7104 scope
• Measurement point every 18 turns– 64 turns is really 1100
turns
• Phase error of ~11 degrees (~0.55 ns)– Resolution ~ 1 degree (50
ps)
1 2 3 4
October 28-31, 2002 DoE Review - Instrumentation - BLT 21
f Tevatron Digital Receiver BLT
RF
Beam Sync
PC
Gate
Controller
UCD
A
B
A
B
Dig
LabViewACNET
Horz
Vert
VXI
30 MHz LPRF amp
30 MHz LPRF amp
30 MHz LPRF amp
30 MHz LPRF amp
Software version of Digital Receiver system for pbars
• 30 MHz LP to ring single 53 MHz bunch– Ring for ~100 ns
• Digitize at 100 MHz
• Correlate with normalized response function
• Generate position and bunch phase for >1024 turns
October 28-31, 2002 DoE Review - Instrumentation - BLT 22
f TeV Digital Receiver BLT
Horizontal Tunes Vertical Tunes
October 28-31, 2002 DoE Review - Instrumentation - BLT 23
f TeV Digital Receiver BLT
Vertical Position vs Turn Horizontal Position vs Turn
October 28-31, 2002 DoE Review - Instrumentation - BLT 24
f TeV Digital Receiver BLT
Comparison of position data to theory (courtesy of V. Lebedev)
+ Horizontal Position, --- Difference from fit Position, --- Difference from fitSynchrotron factored out
October 28-31, 2002 DoE Review - Instrumentation - BLT 25
f Tevatron Waveform Movie
Proton injection
Vertical Stripline into fast scope
• Red = A-B
• Blue = A+B
• 1 to 2000 turns by 20
• 0.5 ns sampling
• Negative Vertical Chromaticity
• Longitudinal dampers off
October 28-31, 2002 DoE Review - Instrumentation - BLT 26
f Head-Tail Measurements(courtesy of P. Ivanov)
0 200 400 600 800 1000 1200 1400 1600 1800 20001
0.5
0
0.5
10.75
0.75
xj 10
A j 10
A j 10
1.964 1031 j
0 200 400 600 800 1000 1200 1400 1600 1800 20004
2
0
2
43.213
3.4
xj 10
A j 10
A j 10
1.964 1031 j
Developing of the head-tail instability with dipole longitudinal configuration
Developing of the head-tail instability with monopole longitudinal configuration
October 28-31, 2002 DoE Review - Instrumentation - BLT 27
f Chromaticity Measurement by the Head-Tail Monitor (courtesy of P. Ivanov)
O s c i l l a t i o n o f d i p o l e m o m e n t a l o n g t h e l o n g i t u d i n a l b u n c h l e n g t h :
L
gt
teAtY
cos,
0 headtheat0
0
y B e t a t r o n a n g u l a r f r e q u e n c y s h i f t d u e t o c h r o m a t i c i t y
L i s t h e t o t a l b e t a t r o n p h a s e s h i f t f r o m h e a d t o t a i l
B e t a t r o n p h a s e a d v a n c e f o r o n e a n d t h r e e t u r n s :
MaxTdtn
MaxTdtn
T
T
333
1
30
3
0
100
0
0
0
1300
12
2 fT
yy
Hzfn 30
107.47,0028.0,5725.0sec,5.2
4.3y
October 28-31, 2002 DoE Review - Instrumentation - BLT 28
f Summary
• Tevatron, Main Injector 53MHz and Recycler 2.5 MHz operational for injection closing
• Main Injector 2.5 MHz being installed
• Upgrades progressing for Tevatron and Main Injector 53 MHz systems
• Multi-systems need to be evaluated and decision made on priorities and how many systems to support– Advantages and disadvantages of each system
– Need to guard against over design
October 28-31, 2002 DoE Review - Instrumentation - BLT 29
f Cast of Characters
Instrumentation:Jim Crisp, Brian Fellenz, Eugene Lorman, Warren Schappert
Pbar Source: Dave McGinnis
Tevatron: Petr Ivanov, Valeri Lebedev
Advise and Consent: Church, Pasquinelli, Pordes and others
…with apologies to anyone forgotten