IBIC2022 - List of Authors (Hillert, W.)

Paper	Title	Page
MOP28	Improvements in Longitudinal Phase Space Tomography at PITZ	105
	N. Aftab, Z. Aboulbanine, P. Boonpornprasert, G.Z. Georgiev, J. Good, M. Groß, A. Hoffmann, M. Krasilnikov, X.-K. Li, A. Lueangaramwong, R. Niemczyk, A. Oppelt, H.J. Qian, C.J. Richard, F. Stephan, G. Vashchenko DESY Zeuthen, Zeuthen, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany A.J. Reader KCL, London, United Kingdom
	Methodical studies to improve the longitudinal phase space (LPS) tomography of space-charge dominated electron beams were carried out at the Photo Injector Test facility at DESY in Zeuthen (PITZ). An analytical model was developed to quantify mean momentum, RMS energy spread, bunch length and phase advance. Phase advance analysis determined the booster phase scan range and step size to be used for obtaining momentum projections. A slit was introduced before the booster to truncate the beam in transverse plane to strongly reduce the space charge effects. The signal resolution of this truncated beam was improved by careful beta function control at the reference screen of the momentum measurements. The reconstruction algorithm was changed from Algebraic Reconstruction Technique (ART) to Image Space Reconstruction Algorithm (ISRA) owing to its assurance of non-negative solutions. In addition, the initial physically justified assumption of LPS, based on low-energy section measurements, was established to clear out noise-like artefacts. This paper will highlight the improvements made in the LPS tomography and compare the simulated and experimental results.
DOI •	reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP28
About •	Received ※ 06 September 2022 — Revised ※ 12 September 2022 — Accepted ※ 13 September 2022 — Issue date ※ 15 October 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP37	Beam Polarization Measurements with the Revised Compton Polarimeter at ELSA	137
	M.T. Switka, K. Desch, D. Elsner ELSA, Bonn, Germany W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The Compton Polarimeter at the ELSA 3.2 GeV storage ring has been designed to measure the polarization degree of the stored electron beam by analyzing the profile of the back-scattered gamma-beam with a silicon microstrip detector. Utilizing a scattering asymmetry from interaction with circularly polarized laser light, the electron beam polarization is determined from the vertical shift of the gamma-beam’s center of gravity in respect to the handedness of the laser light. The installation of a new laser source and silicon strip detector has improved the polarimeter’s performance significantly. Additionally, the profile analysis could be enhanced by using a Pearson type peak function fit. The analyzing power was determined through the observation of the Sokolov-Ternov effect and a statistical measurement accuracy of 2 % could be obtained within 5 minutes of measurement time. The polarimeter resolves the expected spin dynamical effects occurring in the storage ring and has shown to be a robust and reliable measurement system for operation with the GaAs source for polarized electrons.
DOI •	reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP37
About •	Received ※ 07 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 13 September 2022 — Issue date ※ 19 September 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Improvements in Longitudinal Phase Space Tomography at PITZ

105

N. Aftab, Z. Aboulbanine, P. Boonpornprasert, G.Z. Georgiev, J. Good, M. Groß, A. Hoffmann, M. Krasilnikov, X.-K. Li, A. Lueangaramwong, R. Niemczyk, A. Oppelt, H.J. Qian, C.J. Richard, F. Stephan, G. Vashchenko
DESY Zeuthen, Zeuthen, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
A.J. Reader
KCL, London, United Kingdom

Methodical studies to improve the longitudinal phase space (LPS) tomography of space-charge dominated electron beams were carried out at the Photo Injector Test facility at DESY in Zeuthen (PITZ). An analytical model was developed to quantify mean momentum, RMS energy spread, bunch length and phase advance. Phase advance analysis determined the booster phase scan range and step size to be used for obtaining momentum projections. A slit was introduced before the booster to truncate the beam in transverse plane to strongly reduce the space charge effects. The signal resolution of this truncated beam was improved by careful beta function control at the reference screen of the momentum measurements. The reconstruction algorithm was changed from Algebraic Reconstruction Technique (ART) to Image Space Reconstruction Algorithm (ISRA) owing to its assurance of non-negative solutions. In addition, the initial physically justified assumption of LPS, based on low-energy section measurements, was established to clear out noise-like artefacts. This paper will highlight the improvements made in the LPS tomography and compare the simulated and experimental results.

DOI •

reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP28

About •

Received ※ 06 September 2022 — Revised ※ 12 September 2022 — Accepted ※ 13 September 2022 — Issue date ※ 15 October 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP37

Beam Polarization Measurements with the Revised Compton Polarimeter at ELSA

137

M.T. Switka, K. Desch, D. Elsner
ELSA, Bonn, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The Compton Polarimeter at the ELSA 3.2 GeV storage ring has been designed to measure the polarization degree of the stored electron beam by analyzing the profile of the back-scattered gamma-beam with a silicon microstrip detector. Utilizing a scattering asymmetry from interaction with circularly polarized laser light, the electron beam polarization is determined from the vertical shift of the gamma-beam’s center of gravity in respect to the handedness of the laser light. The installation of a new laser source and silicon strip detector has improved the polarimeter’s performance significantly. Additionally, the profile analysis could be enhanced by using a Pearson type peak function fit. The analyzing power was determined through the observation of the Sokolov-Ternov effect and a statistical measurement accuracy of 2 % could be obtained within 5 minutes of measurement time. The polarimeter resolves the expected spin dynamical effects occurring in the storage ring and has shown to be a robust and reliable measurement system for operation with the GaAs source for polarized electrons.

DOI •

reference for this paper ※ doi:10.18429/JACoW-IBIC2022-MOP37

About •

Received ※ 07 September 2022 — Revised ※ 09 September 2022 — Accepted ※ 13 September 2022 — Issue date ※ 19 September 2022

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)