Longitudinal beam dynamic

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25 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Longitudinal beam dynamic
simulation of CTF3 (CL & CT) with
MathCAD ,Placet and Parmila and an
initial bunch length measurement

Seyd

Hamed
Shaker,IPM

1

Comparison between MathCAD, Placet
and Parmila

Seyd Hamed Shaker,IPM

2

1
-

The base program is MathCAD and focus on
Longitudinal simulation and at the moment contains
Wakefield effect and no space charge effect.


2
-

Parmila was used by Peter Urschütz to calculate
beam after Injector(point A) and after girder 3(point
B) and after first chicane(point C) and contains space
charge effect and no Wakefield effect.

3
-

Placet model that Andrea Latina gave me starts
from point C and was used for point D and E and
contains Wakefield effect and no space charge effect.


Point A (after Injector) with Parmila

Seyd Hamed Shaker,IPM

0
1
2
3
4
5
6
7
-40
-20
0
20
40
60
80
100
120
Energy (MeV)

Phase (Degree)

Energy
-

Phase @ point A

3

Seyd Hamed Shaker,IPM

4

Point B with
Parmila

and
MathCAD
(without Wakefield effect)

Point C(after chicane) with
Parmila

and
MathCAD(without Wakefield effect)

Seyd Hamed Shaker,IPM

5

Point C with MathCAD
with

and
without

W
akefield effect

Seyd Hamed Shaker,IPM

6

Point D(after Girder 15) with
MathCAD

and
Placet

Seyd Hamed Shaker,IPM

7

Point D with MathCAD
with

and
without

Wakefield effect

Seyd Hamed Shaker,IPM

8

Point E with MathCAD
with

and
without

phase changing of Girder 15

Seyd Hamed Shaker,IPM

We changed the phase
of Girder 15 by 20⁰.

R56=0.45 here

9

Bunch length calculation per phase of
Girder 15 in point E with MathCAD

Seyd Hamed Shaker,IPM

R56=0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
40
60
80
100
120
140
160
phase(degree)
rms(mm)
R56=0.2
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
0
20
40
60
80
phase(degree)
rms(mm)
0.5
1
1.5
2
2.5
3
3.5
4
-200
-150
-100
-50
0
rms(mm)

phase(degree)

R56=
-
0.2

10

Seyd Hamed Shaker,IPM

11

Non
-
linearity between
c∆t

and ∆P/P and
transverse correlation in Placet model

Calibration of device


RF Deflector

Chicane optics & bunch length measurements
-

2004

Magnetic chicane (4 dipoles)

RF Deflector

Screen

Betatron phase advance

(cavity
-
profile monitor)

Beta function at cavity


and profile monitor

Beam energy

RF deflector phase

RF deflector

wavelength

Deflecting Voltage

Bunch length

s
y0

s
y

Deflecting mode


TM
11

RF deflector off

RF deflector on

13/25

A. Dabrowski, 17 October 2007

CTF3 Technical meeting

Bunch length monitoring

Measurement RF deflector 2007

Measurement method( “scan” method)


Slide H. Shaker

Change the 1.5 GHz RF deflector phase and measure the
average intensity of a thin band on the middle of screen per
each phase. The phase of RFD related to bunch length by c/f
factor. (c is speed of light and f=1.5 GHz)

Standard deviation * c/f =
2.84
±

0.35 mm

-15
-10
-5
0
5
10
15
20
-20
-10
0
10
20
Phase of RFD (degree)

Average Intensity

Measurement RF deflector 2006
-
2007

“Single Image” method:


1) Measure the bunch length in monitor in pixel
units for a
single image

2)
Calibrate

the monitor by finding the
equivalence between pixel unit and length unit
(mm) by
measuring the relationship between
the center of the image position per RF
deflector phase


Advantage

“Scan” method vs. “Single Image”
method
:



Avoid non
-
linearity

effects from the screen


Image can be bigger than the screen
(
improved resolution
)


Disadvantage:



Need to
assume bunch shape remains
constant

during the scan

Slide H. Shaker

Example of Calibration curve for “Single
Image” method ref.
D.Alesini et al
CTFF3
-
010
INFN

Measurement RF deflector 2007

Slide H. Shaker

1.50
1.70
1.90
2.10
2.30
2.50
2.70
2.90
3.10
3.30
3.50
0
1
2
3
4
5
6
7
8
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
215
220
225
230
235
240
245
250
255
May 2007


Bunch length = 2.45
±

0.28 mm

Phase of MKS constant for 7
measurements, “Scan” method used

December 2007


Example:

Bunch length @ 240 degrees
MKS13 = 2.75
±

0.27 mm


Bunch Length (mm)

Bunch Length (mm)

Klystron 13 Phase (degree)