FLS2023 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
TU4P05	Design of the Test Platform for High Current VHF Electron Gun	electron, gun, cathode, emittance	80
	Z.P. Liu, X.D. Li SINAP, Shanghai, People’s Republic of China H.X. Deng, Z.G. Jiang SARI-CAS, Pudong, Shanghai, People’s Republic of China H.J. Qian DESY Zeuthen, Zeuthen, Germany G. Shu IHEP, Beijing, People’s Republic of China
	A high-average-current VHF electron gun operating in the CW mode is under construction at Shanghai Advanced Research Institute, which is the key component of a kW-power-order free electron laser facility. The average current and the frequency of this electron gun is 1-10 mA and 217 MHz, respectively. To validate the performance of this instrument, a test platform has been designed. The R&D of its vacuum and diagnostics are presented in this work.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P05
About •	Received ※ 23 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P17	Non-destructive Vertical Halo-monitors on the ESRF Electron Beam	electron, emittance, SRF, diagnostics	112
	K.B. Scheidt ESRF, Grenoble, France
	The ESRF EBS storage ring has since spring 2022 among its electron beam diagnostics two independent units of vertical Halo-monitors. The principle and the components of this unique diagnostic will be explained in details. It uses the available X-rays in a non-used Front-End, emitted from a 0.57 T standard dipole magnet in the EBS lattice. This instrument measures the so-called "far-away" Halo level, i.e. in a zone of roughly 1-3 mm away from the beam centre, which represents 200-600 times the electron’s vertical beam-size, supposedly Gaussian, of 5 um. It is measured, and expressed quantitively in picoAmp beam current, at 1 Hz rate. Both units are yielding very satisfying and well-correlated results that will be presented in details, and in relation with studies on the electron beam and the accelerator components like variation of current, filling-patterns, vertical emittance, quality of the vacuum, settings of the undulator gaps, collimators, scrapers etc. and also in direct correlation with measurements of our 128 beamloss detectors and beam lifetime.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P17
About •	Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P36	The Cryogenic Undulator Upgrade Programme at Diamond Light Source	undulator, MMI, cryogenics, insertion-device	211
	Z. Patel, W. Cheng, A. George, S.H. Hale, R. Mercado, A. Ramezani Moghaddam, M. Reeves, G. Sharma, S. Tripathi DLS, Oxfordshire, United Kingdom M.V. Marziani University of Cape Town, Cape Town, South Africa
	Diamond Light Source has installed four 2 m long, 17.6 mm period Cryogenic Permanent Magnet Undulators (CPMUs) as upgrades for crystallography beamlines since 2020, with two more planned within the next year. The CPMUs provide 2 - 3 times more brightness and 2 - 4 times more flux than the pure permanent magnet (PPM) devices they are replacing. They have been designed, built, and measured in-house. All four have a 4 mm minimum operating gap and are almost identical in their construction: the main difference being an increase in the number of in-vacuum magnet beam support points from four to five, between CPMU-1 and CPMUs 2 - 4, to better facilitate shimming, particularly at cold temperatures. The ability to shim at cryogenic temperatures necessitated the development of an in-vacuum measurement system. The details of the measurement system will be presented alongside the mechanical and cryogenic design of the undulators; including issues with the magnet foils, and the shimming procedures and tools used to reach the tight magnetic specifications at room temperature and at 77 K.
	Poster WE4P36 [1.656 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P36
About •	Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P38	Pulsed Wire Measurement of 20 mm Period Hybrid Undulator and Effects of Dispersion	undulator, experiment, laser, insertion-device	218
	S.M. Khan, G. Mishra Devi Ahilya University, Indore, India M. Gehlot DESY, Hamburg, Germany
	In the pulsed wire method, a thin wire is stretched along the undulator axis with a sensor located near the undulator end. When a current flows through the wire, the Lorentz force on the wire sets up a travelling wave that is picked up by a sensor. Sensor output v. time gives the field integral v. position along the undulator length. We investigate pulsed wire measurements of field integrals and phase error of a 20 mm-period, 500 mm-long undulator and discuss variation in performance with Hall probe data, without any dispersion correction algorithm. Dispersion in the wire introduces dispersion corrected pulse lengths for the field integral measurements. Two field integrals of the undulator were measured with an accuracy close to 2 Gcm and 2 Gcm² with the Hall probe result. The contributions of dispersion to the phase error of the undulator are analyzed. The dispersion assisted phase advance in the undulator in the pulsed wire is measured with a higher slope in comparison to the Hall probe data. Dispersion limited optical phase growth along the undulator length causes period length fluctuations and yields a discrepancy in the phase error computation in comparison to Hall probe data.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P38
About •	Received ※ 22 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TH3B2	Novel X-ray Beam Position Monitor for Coherent Soft X-ray Beamlines	detector, undulator, operation, photon	241
	B. Podobedov, D.M. Bacescu, C. Eng, S. Hulbert, C. Mazzoli, C.S. Nelson BNL, Upton, New York, USA D. Donetski, K. Kucharczyk, J. Liu, R. Lutchman, J. Zhao Stony Brook University, Stony Brook, New York, USA
	A novel soft X-ray BPM (sXBPM) for high-power white beams of synchrotron undulator radiation is being developed through a joint effort of BNL/NSLS-II and Stony Brook University. In our approach, custom-made multi-pixel GaAs detector arrays are placed into the outer portions of the X-ray beam, and the beam position is inferred from the pixel photocurrents. Our goal is to achieve micron-scale positional and ~50 nrad angular resolution without interfering with user experiments, especially the most sensitive ones exploiting coherent properties of the beam. To this end, an elaborate mechanical system has been designed, fabricated, and installed in the 23-ID canted undulator beamline first optical enclosure, which allows positioning of the detectors with micron-scale accuracy, and provisions for possible intercepts of kW-level beam in abnormal conditions. Separately, GaAs detectors with specially tailored spectral response have been designed, fabricated, and tested in the soft and hard X-ray regions at two NSLS-II beamlines. In this talk we plan to give an overview of the sXBPM system and present the first results from the high-power white X-ray beam.
	Slides TH3B2 [5.100 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH3B2
About •	Received ※ 15 September 2023 — Revised ※ 15 September 2023 — Accepted ※ 17 September 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TU4P05

Design of the Test Platform for High Current VHF Electron Gun

electron, gun, cathode, emittance

80

Z.P. Liu, X.D. Li
SINAP, Shanghai, People’s Republic of China
H.X. Deng, Z.G. Jiang
SARI-CAS, Pudong, Shanghai, People’s Republic of China
H.J. Qian
DESY Zeuthen, Zeuthen, Germany
G. Shu
IHEP, Beijing, People’s Republic of China

A high-average-current VHF electron gun operating in the CW mode is under construction at Shanghai Advanced Research Institute, which is the key component of a kW-power-order free electron laser facility. The average current and the frequency of this electron gun is 1-10 mA and 217 MHz, respectively. To validate the performance of this instrument, a test platform has been designed. The R&D of its vacuum and diagnostics are presented in this work.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P05

About •

Received ※ 23 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

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

TU4P17

Non-destructive Vertical Halo-monitors on the ESRF Electron Beam

electron, emittance, SRF, diagnostics

112

K.B. Scheidt
ESRF, Grenoble, France

The ESRF EBS storage ring has since spring 2022 among its electron beam diagnostics two independent units of vertical Halo-monitors. The principle and the components of this unique diagnostic will be explained in details. It uses the available X-rays in a non-used Front-End, emitted from a 0.57 T standard dipole magnet in the EBS lattice. This instrument measures the so-called "far-away" Halo level, i.e. in a zone of roughly 1-3 mm away from the beam centre, which represents 200-600 times the electron’s vertical beam-size, supposedly Gaussian, of 5 um. It is measured, and expressed quantitively in picoAmp beam current, at 1 Hz rate. Both units are yielding very satisfying and well-correlated results that will be presented in details, and in relation with studies on the electron beam and the accelerator components like variation of current, filling-patterns, vertical emittance, quality of the vacuum, settings of the undulator gaps, collimators, scrapers etc. and also in direct correlation with measurements of our 128 beamloss detectors and beam lifetime.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P17

About •

Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

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

WE4P36

The Cryogenic Undulator Upgrade Programme at Diamond Light Source

undulator, MMI, cryogenics, insertion-device

211

Z. Patel, W. Cheng, A. George, S.H. Hale, R. Mercado, A. Ramezani Moghaddam, M. Reeves, G. Sharma, S. Tripathi
DLS, Oxfordshire, United Kingdom
M.V. Marziani
University of Cape Town, Cape Town, South Africa

Diamond Light Source has installed four 2 m long, 17.6 mm period Cryogenic Permanent Magnet Undulators (CPMUs) as upgrades for crystallography beamlines since 2020, with two more planned within the next year. The CPMUs provide 2 - 3 times more brightness and 2 - 4 times more flux than the pure permanent magnet (PPM) devices they are replacing. They have been designed, built, and measured in-house. All four have a 4 mm minimum operating gap and are almost identical in their construction: the main difference being an increase in the number of in-vacuum magnet beam support points from four to five, between CPMU-1 and CPMUs 2 - 4, to better facilitate shimming, particularly at cold temperatures. The ability to shim at cryogenic temperatures necessitated the development of an in-vacuum measurement system. The details of the measurement system will be presented alongside the mechanical and cryogenic design of the undulators; including issues with the magnet foils, and the shimming procedures and tools used to reach the tight magnetic specifications at room temperature and at 77 K.

Poster WE4P36 [1.656 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P36

About •

Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

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

WE4P38

Pulsed Wire Measurement of 20 mm Period Hybrid Undulator and Effects of Dispersion

undulator, experiment, laser, insertion-device

218

S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India
M. Gehlot
DESY, Hamburg, Germany

In the pulsed wire method, a thin wire is stretched along the undulator axis with a sensor located near the undulator end. When a current flows through the wire, the Lorentz force on the wire sets up a travelling wave that is picked up by a sensor. Sensor output v. time gives the field integral v. position along the undulator length. We investigate pulsed wire measurements of field integrals and phase error of a 20 mm-period, 500 mm-long undulator and discuss variation in performance with Hall probe data, without any dispersion correction algorithm. Dispersion in the wire introduces dispersion corrected pulse lengths for the field integral measurements. Two field integrals of the undulator were measured with an accuracy close to 2 Gcm and 2 Gcm² with the Hall probe result. The contributions of dispersion to the phase error of the undulator are analyzed. The dispersion assisted phase advance in the undulator in the pulsed wire is measured with a higher slope in comparison to the Hall probe data. Dispersion limited optical phase growth along the undulator length causes period length fluctuations and yields a discrepancy in the phase error computation in comparison to Hall probe data.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P38

About •

Received ※ 22 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

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

TH3B2

Novel X-ray Beam Position Monitor for Coherent Soft X-ray Beamlines

detector, undulator, operation, photon

241

B. Podobedov, D.M. Bacescu, C. Eng, S. Hulbert, C. Mazzoli, C.S. Nelson
BNL, Upton, New York, USA
D. Donetski, K. Kucharczyk, J. Liu, R. Lutchman, J. Zhao
Stony Brook University, Stony Brook, New York, USA

A novel soft X-ray BPM (sXBPM) for high-power white beams of synchrotron undulator radiation is being developed through a joint effort of BNL/NSLS-II and Stony Brook University. In our approach, custom-made multi-pixel GaAs detector arrays are placed into the outer portions of the X-ray beam, and the beam position is inferred from the pixel photocurrents. Our goal is to achieve micron-scale positional and ~50 nrad angular resolution without interfering with user experiments, especially the most sensitive ones exploiting coherent properties of the beam. To this end, an elaborate mechanical system has been designed, fabricated, and installed in the 23-ID canted undulator beamline first optical enclosure, which allows positioning of the detectors with micron-scale accuracy, and provisions for possible intercepts of kW-level beam in abnormal conditions. Separately, GaAs detectors with specially tailored spectral response have been designed, fabricated, and tested in the soft and hard X-ray regions at two NSLS-II beamlines. In this talk we plan to give an overview of the sXBPM system and present the first results from the high-power white X-ray beam.

Slides TH3B2 [5.100 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH3B2

About •

Received ※ 15 September 2023 — Revised ※ 15 September 2023 — Accepted ※ 17 September 2023 — Issued ※ 02 December 2023

Cite •

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