Download - Development of a Chromaticity measurement application using Head-Tail phase shift technique
![Page 1: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/1.jpg)
Development of a Chromaticity measurement application using
Head-Tail phase shift technique.
![Page 2: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/2.jpg)
Overview
• Discussion of measurement needs in the Tevatron
• Introduction to Theory of Head-Tail Phase Shift
• Results from initial tests in the Tevatron• Coupling and Bunch Amplitude profiles• Limitations of current set-up• Conclusion
![Page 3: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/3.jpg)
Measurement needs in the Tevatron
• Moving from uncoalesced to coalesced protons during machine tune-up
• Measurement during Acceleration ramp.
- Chromaticity, Tune, and Coupling.
• Current RF chromaticity system draw-backs
- Requires uncoalesced protons
- Requires three acceleration ramps.
![Page 4: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/4.jpg)
H T
P/P
s
Longitudinal ‘phase-space’ Graph
Longitudinal Beam Dynamics
![Page 5: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/5.jpg)
Chromaticity Measurement Using Head-Tail Phase Shift In the presence of non-zero chromaticity the betatron equation of motion becomes:
Thus from phase difference between two locations in a bunch the chromaticity can be calculated:
)1)2(cos(2cos so nqnY
)1)2(cos(
so nq
![Page 6: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/6.jpg)
Using the vertical and horizontal strip-line detectors installed in the Tevatron at the F0 location we extract a profile of the transverse behavior of the beam over a single longitudinal bunch.
Extracting Transverse position
![Page 7: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/7.jpg)
Difference Signal (A-plate – B-plate)
Reflected Signal
Reconstructed Signal
Sum Signal (A-plate + B-plate)
The Raw Signal is Processed to remove the Reflected Signal
0 10 20 30 40 50 60 70 80 900.4
0.2
0
0.2
0.4
Sj
RSj
j
0 10 20 30 40 50 60 70 80 900.1
0
0.1
D j
RD j
j
![Page 8: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/8.jpg)
Turn by Turn Sum(A+B) Profile from Strip-line monitor
S
![Page 9: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/9.jpg)
From the Sum and Difference (A-plate B-plate) Signals the Transverse position can be calculated using: Here G is the ratio of the A-B gain over the A+B gain.Once the Transverse Position as a function of longitudinal bunch position is known () we can use this to analyze the phase shift between the Head and the Tail to Calculate Chromaticity.
,,
,,27,nBnASumnBnADifferenceGnX
![Page 10: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/10.jpg)
Vertical and Horizontal turn by turn position after horizontal 1.6 mm kick
0 100 200 300 400 500 600 700 800 900 1000 1100 12002
0
2
4
Center i
i
0 100 200 300 400 500 600 700 800 900 1000 1100 12001
1.5
2
2.5
3
Centery i
i
![Page 11: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/11.jpg)
0.5 0.55 0.60
0.1
0.2
Amp i2
NN
i
NN0 100 200 300 400 500 600 700 800 900 1000 1100 1200
0
1
2
3
Center i
i
0 100 200 300 400 500 600 700 800 900 1000 1100 12002
0
2
4
Centery i
i
Vertical and Horizontal turn by turn position after vertical 1.75 mm kick
![Page 12: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/12.jpg)
Difference in Head Tail Phase EvolutionQ'=7.49
-40
-20
0
20
40
60
80
100
120
0 100 200 300 400 500 600 700
Turn Number
Dif
fere
nce
in
Ph
ase
(Deg
rees
)
![Page 13: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/13.jpg)
Chromaticity CalculationQ'=7.49
0
2
4
6
8
10
12
14
250 260 270 280 290 300 310
Turn Number
Q'
Take Average Across 40 Turns around 1/2 Synchrotron Period Q' = 7.49
![Page 14: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/14.jpg)
0
2
4
6
8
10
12
14
30 32 34 36 38 40 42
Horizontal Chrom. Set point
Ho
rizo
nta
l M
easu
red
Ch
rom
.
RF
Head Tail
![Page 15: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/15.jpg)
0
1
2
3
4
5
6
7
8
9
10
25 27 29 31 33 35
Vertical Chrom. Set point
Ver
tica
l M
easu
red
Ch
rom
.
RF
Head Tail
![Page 16: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/16.jpg)
Other measurements
• Coupling
• Bunch Amplitude
max
21maxmin
||||
Y
XQ
Aj mm
1
4 sin 2X
j 1 mm Xj 1 mm 2 X
j mm 2 tan 2 Xj 1 mm X
j 1 mm 2
![Page 17: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/17.jpg)
A
Ay
Color Contour Plot of Bunch Amplitude after 1.6 mm Horizontal kick after first 2.5 sec of ramp.
![Page 18: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/18.jpg)
Cv=-0.93 Ch=5.1
A
Instability Studies Performed Last Spring: (Jim Crisp, Peter Ivanov)
![Page 19: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/19.jpg)
Cv= -2.1 Ch = 6.2
A
![Page 20: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/20.jpg)
A
Cv = -5.1 Ch = 6.2
![Page 21: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/21.jpg)
A
Cv =-6.43 Ch =6.3
![Page 22: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/22.jpg)
Tunes up the ramp
0.568
0.57
0.572
0.574
0.576
0.578
0.58
0.582
0.584
0.586
0.588
0.59
0 100 200 300 400 500 600 700 800
GeV
Qx
Qy
Results from most recent tests during ramp:
![Page 23: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/23.jpg)
Coupling up the ramp
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0 100 200 300 400 500 600 700 800
GeV
![Page 24: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/24.jpg)
Chromaticity up the ramp
0
2
4
6
8
10
12
14
0 100 200 300 400 500 600 700 800
GeV
AvgCx
AvgCy
![Page 25: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/25.jpg)
E17 kicker delay vs. Voltage
0
100
200
300
400
500
600
700
800
900
0 1 2 3 4 5 6 7 8 9 10
kV
mic
ro s
ec
s o
f d
ela
y
Timing of E17 vertical kicker
![Page 26: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/26.jpg)
Screen Shots of Software
![Page 27: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/27.jpg)
![Page 28: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/28.jpg)
![Page 29: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/29.jpg)
![Page 30: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/30.jpg)
![Page 31: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/31.jpg)
![Page 32: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/32.jpg)
![Page 33: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/33.jpg)
![Page 34: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/34.jpg)
![Page 35: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/35.jpg)
![Page 36: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/36.jpg)
Limitations of current set-up
• The major drawback of this system of measurement is its destructiveness. For measurement during tune up current system is ok. For a store we need more work.
• In addition both the kickers and scope have limitations which restrict operations.
![Page 37: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/37.jpg)
F17 and E17 kickers
• The Horizontal kicker requires a ramp up time of 2.5 secs. (~30 possible horiz. Meas.)
• The E17 kicker produces a half sinusoid current pulse with a base width of 10 micro secs. The F17 kicker produces a square current pulse with a width of 1.8 micro secs.
• Thus the E17 kicker is too slow hit only one bunch during 36x36 store. But the F17 kicker could accomplish this if fired at the right time in the abort gap.
![Page 38: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/38.jpg)
Scope
• With all four channels Scope can store only 12048 turns which means the max number of measurements possible is 23 (every-other-turn).
• The scope resolution is limited by the bit size and closed-orbit offset which set our minimum resolution to .1 mm.
![Page 39: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/39.jpg)
Moving towards less destructive measurements
• By removing the closed-orbit current offset we should be able to reduce this resolution down to the signal noise floor from the beam and cables. Thus we could increase effective scope resolution and possibly reduce the required kick amplitude.
• Excite beam adiabatically (ac dipole technique)• Run the damper kickers resonantly. This method
of chirp excitation has been tested successfully at HERA . Can be gated to hit only one bunch.
![Page 40: Development of a Chromaticity measurement application using Head-Tail phase shift technique](https://reader037.vdocuments.us/reader037/viewer/2022110321/56649cdb5503460f949a5ad1/html5/thumbnails/40.jpg)
Conclusion
• This system is nearing completion – Last major issue: E17 kicker timing– Rigrous comparison with RF technique on ramp.
• Now time for beam physics studies:– Study chromaticity and coupling changes during ramp.– Study of Bunch amplitude using color contour plots
• Possible future improvements– Minimally destructive measurements – Measure beam-beam effects on chromaticity and coupling.– Measure Pbars?