| Paper | Title | Page |
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| TUP13 | Standard Button BPMs for PETRA IV | 249 |
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| A new diffraction limited light source PETRA IV (DESY, Germany) with ultra-low emittance is currently being designed as an upgrade of the 3rd generation light source PETRA III. For transverse beam position measurements, beam position monitors (BPMs) will be used as an essential part of the beam diagnostic system. There will be a total of about 800 BPMs distributed along the 2.3 km storage ring. The inner diameter of the standard beam pipe, and therefore of most of the BPM chambers, will be 20 mm. The primary purpose of the systems is to provide high-resolution measurements of the transverse position of the electron beam. By specification, the impact of the mechanical tolerances on the position readings should be below 150 microns which is essential for the commissioning of the machine. To achieve this goal, the dependence of the accuracy of the beam position measurement on the tolerances of each manufactured part of the BPM was studied. This paper summarizes the development and optimization of each part of the BPM by using EM simulations performed with CST Studio Suite. | ||
| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP13 | |
| About • | Received ※ 07 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 01 October 2022 | |
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| TUP21 | Scintillator Nonproportionality Studies at PITZ | 277 |
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A standard technique to measure beam profiles in linear accelerators are screen monitors using scintillating screens. This technique is used e.g. at the European XFEL in order to overcome coherence effects in case of OTR usage [*]. During the XFEL commissioning it was found out that screens based on LYSO:Ce as scintillating material revealed a nonproportional light output [**]. Reason for it is the high particle beam density. As consequence it was decided to exchange LYSO:Ce by GAGG:Ce scintillators because the excitation carriers can rapidly transfer their energy to excited states of gadolinium, and a rapid migration of this energy among the Gd sub-lattice is expected. Driven by the observations at XFEL a series of measurements was started to investigate the properties of various scintillator materials (LYSO:Ce, YAP:Ce, YAG:Ce, LuAG:Ce and GAGG:Ce). The last measurement campaign was carried out at PITZ which allows to operate at higher beam charge and lower electron energy compared to the XFEL. The present work summarizes the results of these measurements.
* S.Wesch and B.Schmidt, in Proc. DIPAC’11, Hamburg, WEOA01, pp. 539-543. ** G.Kube, A.Novokshonov, S.Liu, M.Scholz, in Proc. FEL’19, Hamburg, WEB01, pp. 301-306. |
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| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-TUP21 | |
| About • | Received ※ 11 September 2022 — Revised ※ 13 September 2022 — Accepted ※ 11 October 2022 — Issue date ※ 15 October 2022 | |
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| WEP08 | Upgrade of the BPM Long Term Drift Stabilization Scheme Based on External Crossbar Switching at PETRA III | 395 |
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| PETRA IV at DESY will be an upgrade of the present synchrotron radiation source PETRA III into an ultra low-emittance source with beam emittance of about 20 pm.rad which imposes stringent requirements on the machine stability. In order to measure beam positions and control orbit stability to the required level of accuracy, a high resolution BPM system will be installed which consists of about 800 monitors with the readout electronics based on MTCA.4. In order to fulfill the requested long-term drift requirement (< 1 micron over 7 days), also the BPM cable paths have to be stabilized because of the PETRA-specific machine geometry. To achieve this, the crossbar switching concept was extended such that the analogue switching part is separated from the read-out electronics and brought as close as possible to the BPM pickup. While first measurements were presented before, meanwhile the system has undergone a major revision, especially the external switching matrix changed from a prototype setup to a system close to the final design. This contribution summarizes the latest measurements from PETRA III, demonstrating the high performance of the external stabilization concept. | ||
| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-WEP08 | |
| About • | Received ※ 07 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 18 October 2022 | |
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| WEP09 | Preliminary Evaluation of the MTCA.4 BPM Electronics Prototype for the PETRA IV Project | 399 |
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| Within the PETRA IV project at DESY, the synchrotron radiation source PETRA III will be upgraded into a low-emittance source. The small beam emittance and reduced beam size imply stringent requirements on the machine stability. To meet the requirements on position measurement and orbit stability, a high-resolution BPM system will be installed in the new machine, with about 800 BPMs and MTCA.4-based readout electronics. In the TDR phase of the project, I-Tech and DESY are cooperating on the realization of a BPM prototype that will demonstrate the feasibility of reaching the PETRA IV requirements. Several analog, digital and SW parts are taken from the Libera Brilliance+ instrument and are reused in the MTCA.4 BPM prototype, with some innovations. One of them is the separation of the RF switch matrix used for long-term stabilization: placing it near the BPM enables also the long RF cables to be stabilized. An 8 channel RTM board, able to acquire signals from two BPMs was developed and is also tested. This paper presents an overview of the BPM electronics prototype and the promising test results achieved in the Instrumentation Technologies’ laboratory with the first boards produced. | ||
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Poster WEP09 [3.499 MB] | |
| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-WEP09 | |
| About • | Received ※ 01 September 2022 — Revised ※ 11 September 2022 — Accepted ※ 12 September 2022 — Issue date ※ 23 September 2022 | |
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| WEP20 | Emittance Diagnostics at PETRA IV | 430 |
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| The PETRA IV project will be a Diffraction Limited Light Source designed to be the successor of PETRA III, the 6 GeV 3rd generation hard X-Ray synchrotron light source at DESY in Hamburg. It will operate at a beam energy of 6 GeV with a design emittance of 20/4 pm rad. For a precise emittance online control, two dedicated diagnostics beamlines will be built up to image the beam profile with synchrotron radiation in the X-Ray region. With two beamlines, it will be possible to extract both the transverse beam emittances and the beam energy spread. Both beamlines will be equipped with two interchangeable X-Ray optical systems: a pinhole camera system to achieve high dynamic range and a Fresnel Diffractometry system for high resolution measurements in the range 1-18 um. This paper describes the planned setup and deals with the possible limitations. | ||
| DOI • | reference for this paper ※ doi:10.18429/JACoW-IBIC2022-WEP20 | |
| About • | Received ※ 05 September 2022 — Revised ※ 10 September 2022 — Accepted ※ 11 September 2022 — Issue date ※ 26 September 2022 | |
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