bepcii transverse feedback system yue junhui beam instrumentation group ihep , beijing
TRANSCRIPT
![Page 1: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/1.jpg)
BEPCII Transverse Feedback System
Yue Junhui
Beam Instrumentation Group
IHEP, Beijing
![Page 2: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/2.jpg)
Outline
Including three parts:
• The main parameters of BEPCII
• The coupled bunch instability
• The bunch by bunch feedback system
![Page 3: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/3.jpg)
I : Some Parameters of BEPCII
Beam Energy, E GeV 1.89
Circumference, C m 237.53
Total beam current, A 0.91
Bunch current, mA 9.8
Revolution frequency, MHz 1.2621
RF frequency, MHz 499.8
Harmonic Number, h 396
Tunes, 6.57/7.61/0.034
Radiation damping times, ms 25/25/12.5
Number of Bunches, B 93
Bunch spacing, m 2.4
Bunch frequency, MHz 125
0I
bI
0f
RFf
zyx v/v/v
zyx //
bS
bf
![Page 4: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/4.jpg)
The high beam current (0.9 A) and the large number of bunches (93 bunches) may cause the coupled bunch instabilities (CBI) in BEPCII
•
• Two source The higher order modes (HOMs) of RF cavities The resistive wall impedance
• Active feedback systems are required to suppress CBI
II :The Coupled Bunch Instability
Fastest growing time in the case of 99 bunches and 9.8mA per bunch HOMs Resistive wall ECI
Transverse (ms) 26.6 4.3 0.5
Longitudinal (ms) 12.8
![Page 5: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/5.jpg)
• Bunch by bunch feedback system will be used on BEPCII
• The electronics bandwidth should be at least half of the bunch frequency
colliding mode 62.5MHz
synchronous radiation mode 250MHz
• The damping time of transverse feedback system is 0.5ms
III: Bunch by bunch Transverse Feedback System
![Page 6: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/6.jpg)
The Transverse Feedback System
• Schematic diagram
• Front-end electronics
• Signal processing system
• Kicker and power amplifier
• Parameters of Transverse Feedback System
• The experiments of BEPCII TFB
![Page 7: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/7.jpg)
The Schematic Diagram of TFB System
DBM
DBM
y1
y1
y2
A B
CD
H-1
83-4
M/A
CO
M
RG58/U
ZA
3PD
-2
ZA
3PD-2
ZA
3PD
-2
ZA
3PD-2
A B
CD
H-1
83-4
M/A
CO
M
RG58/U
ZA
3PD
-2
ZA
3PD-2
ZA
3PD
-2
ZA
3PD-2
y2Z
FRS
C-42
Mini
ZFR
SC
-42M
ini
BLP-300Mini
BLP-300Mini
ZFR
SC
-42M
ini
y
x
y-x
y+x
x-y
-x-y
M21CCR&K
ZHL-6AMini
DCPower
DCPower
ZHL-6AMini
weinschel3209-1
weinschel3209-1
75A250A
AR
HC
22-27T
el-Tech
HC22-27Tel-Tech
Digit Delay
ZFL-2500Mini
ZFL-2500Mini
HC22-2710K-250MHz
ZHL-6AMini
PADL3-10Gigabaudics
HJ5-50andrew
HJ5-50andrew
weinschel3201-1
ZFL-2500Mini
ZFL-2500Mini
GPS-1830台湾固维
LDF2-50andrew
33311BHP
ZFM-2000Mini
M21CCR&K
3428TARRA
3428TARRA
PDL-30Acol by
3428TARRA RG58/C
ZFR
SC
-42M
ini
Detct i on
ZFR
SC
-42M
ini
Detct i on
MultiFreq(*3)
RF频率
ZFR
SC
-42M
ini
Narda 3752ARRA
ZFM-2000Mini
![Page 8: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/8.jpg)
The local station of the Transverse Feedback System
![Page 9: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/9.jpg)
• Transfer the signal whose bandwidth is 500MHz at the center frequency of 1.5GHz to base band.
• Detection frequency is 1.5GHz, triple of RF.
Front-end electronics
y1A B
CD
BLP-750Mini
ZFM-2000Mini
H-1
83-4
M/A
CO
MH
-183
-4M
/A C
OM
H-1
83-4
M/A
CO
M
X
Y
H-1
83-4
M/A
CO
M
3× f
![Page 10: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/10.jpg)
Signal processing system
• Full analog system simply using the cable line
• Three functions
Making the 90 phase shift
Rejection the closed orbit signal
One turn delay
• Realization
Two manual attenuators for 90 phase shift control
Notch filter rejection the revolution frequency
The time delay by cable
![Page 11: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/11.jpg)
Signal processing system -
Phase shift and Notch Filter
Notch Filter
LDF4-50AAndrew
RG233HC22
27-
10K
-250
MH
z
HC22
27-
10K
-250
MH
z
BMA-3511
SRC-SMJ-205
RSA-3530D
RSA-3530D
combiner
attenuator
phase shift control
x1
x2
![Page 12: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/12.jpg)
Kicker and Power Amplifier
• Four strip line electrode as kicker
(considering it is easy to realize, so the kicker length is 600mm just for every other bunches)
• One kicker per ring because the limited space
• Model 75A250A power amplifier is selected.
• Two 75A250A are connected in the differential style
![Page 13: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/13.jpg)
Kicker and Power Amplifier
![Page 14: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/14.jpg)
Specifications of the TFB system RF frequency MHz 499.8
Bunch spacing ns 8
Feedback damping time ms 0.5
Detection frequency GHz 1.5
Number of kickers per plane per ring 1
Kicker shunt impedance (at 125MHz) k 3.0
Total damping voltage per turn V 800
Kicker power for 800 V w 106
Number of power amplifiers per plane per ring 2
Bandwidth of power amplifier MHz 250
![Page 15: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/15.jpg)
The experiments of BEPCII TFB(1)
With TFB system off, we can observe the vertical and the horizontal sidebands.
![Page 16: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/16.jpg)
Only turn on the y direction TFB, the vertical sidebands disappear and the horizontal sidebands become strong.
The experiments of BEPCII TFB(2)
![Page 17: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/17.jpg)
Turn on x direction TFB, the horizontal sidebands also disappear, the beam size become smaller.
The experiments of BEPCII TFB(3)
![Page 18: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/18.jpg)
Conclusion
In a word , This system can restrain coupled bunch instabilities. But stable and continued run need more efforts and more experiences。
Other parameters need to measure in the future study。
![Page 19: BEPCII Transverse Feedback System Yue Junhui Beam Instrumentation Group IHEP , Beijing](https://reader036.vdocuments.site/reader036/viewer/2022062519/5697bfe31a28abf838cb4b7e/html5/thumbnails/19.jpg)
Thank you very much!