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 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 Wakefield 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)

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 DeflectorScreen

Betatron phase advance(cavity-profile monitor)

Beta function at cavity and profile monitor

Beam energy

RF deflector phase

RF deflectorwavelength

Deflecting Voltage

Bunch length

y0

y

Deflecting mode TM11

RF deflector off RF deflector on

13/25 A. Dabrowski, 17 October 2007CTF3 Technical meetingBunch 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

Phase of RFD (degree)

Aver

age

Inte

nsity

Measurement RF deflector 2006-2007

““Single Image” method:Single Image” method:

1) Measure the bunch length in monitor in pixel units for a single image2) 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

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

Avoid non-linearity effects from the screenImage can be bigger than the screen (improved resolution)

Disadvantage: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

May 2007

Bunch length = 2.45 ± 0.28 mmPhase of MKS constant for 7

measurements, “Scan” method used

December 2007

Example:Bunch length @ 240 degrees

MKS13 = 2.75 ± 0.27 mm

Bunc

h Le

ngth

(mm

)

Bunc

h Le

ngth

(mm

)

Klystron 13 Phase (degree)