| Paper | Title | Other Keywords | Page |
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| MOPOST035 | Operational Experience and Performance of the REX/HIE-ISOLDE Linac | linac, experiment, operation, MMI | 140 |
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| Located at CERN, ISOLDE is one of the world’s lead-ing research facilities in the field of nuclear science. Radioactive Ion Beams (RIBs) are produced when 1.4 GeV protons transferred from the Proton Synchrotron Booster (PSB) to the facility impinge on one of the two available targets. The RIB of interest is extracted, mass-separated and transported to one of the experimental stations, either directly, or after being accelerated in the REX/HIE-ISOLDE post-accelerator. In addition to a Penning trap (REXTRAP) to accumulate and transversely cool the beam and a charge breeder (REXEBIS) to boost the charge state of the ions, the post-accelerator includes a linac with both room temperature (REX linac) and superconducting (HIE-ISOLDE linac) sections followed by three HEBT lines to deliver the beam to the different experimental stations. The latest upgrades of the facility as well as a comprehensive list of the RIBs delivered to the users of the facility and the operational experience gained during the last physics campaigns will be presented in this contribution. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST035 | ||
| About • | Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022 | ||
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| MOPOST036 | Transverse Emittance Measurements of the Beams Produced by the ISOLDE Target Ion Sources | ion-source, target, emittance, quadrupole | 144 |
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| The Isotope mass Separator On-Line DEvice (ISOLDE) is a Radioactive Ion Beam (RIB) facility based at CERN where rare isotopes are produced from 1.4 GeV-proton collisions with a target. The different types of targets and ion sources, operating conditions and ionization schemes used during the physics campaign results in extracted beams with various emittances. Characterizing the beam emittance allows deducing the transport efficiency to low-energy experimental stations (up to 60 keV) and the mass resolving power of the separators. We report on emittance measurements for different beams of stable elements extracted from surface and plasma ion sources. The dependence of the emittance on the different conditions of operation of the ion sources is investigated and the results are compared to previous measurements. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST036 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022 | ||
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| TUPOST019 | Evaluation of PIP-II Master Oscillator Components | proton, controls, linac, SRF | 892 |
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Funding: The paper was prepared by WUT and PIP-II, using the resources of Fermilab, a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is acting under Contract No. DE-AC02-07CH11359. The Proton Improvement Plan-II (PIP-II) is a planned proton facility at Fermilab. The short- and long-term beam energy stabilization requirements necessitate using a high-quality Master Oscillator (MO). The consecutive sections of the Linac will operate at 162.5, 325, and 650 MHz. The phase relations between reference signals of harmonic frequencies should be kept constant, and the phase noise should be correlated in a wide bandwidth. The possibility of simultaneously meeting both requirements using popular frequency synthesis schemes is discussed. The ultra-low noise floor of the fundamental source is challenging for other devices in the phase reference distribution system. Therefore, the sensitivity to operating conditions, including impedance matching, input power level, and power supply voltage, must be considered. This paper presents a preliminary performance test of critical components selected for the PIP-II Master Oscillator system performed using a state-of-the-art phase noise analyzer. The paper was prepared by WUT and PIP-II, using the resources of Fermilab, a U.S. Department of Energy, Office of Science, HEP User Facility. Fermilab is acting under Contract No. DE-AC02-07CH11359. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST019 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022 | ||
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| TUPOPT044 | High-Power Attosecond Pulses via Cascaded Amplification | electron, FEM, laser, experiment | 1101 |
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Funding: This work was supported by US Department of Energy Contracts No. DE-AC02-76SF00. The timescale for electron motion in molecular systems is on the order of hundreds of attoseconds, and thus the time-resolved study of electronic dynamics requires a source of sub-femtosecond x-ray pulses. Here we report the experimental generation of sub-femtosecond duration soft x-ray free electron laser (XFEL) pulses with hundreds of microjoules of energy using fresh-slice amplification in two cascaded stages at the Linac Coherent Light Source. In the first stage, an enhanced self-amplified spontaneous emission (ESASE) pulse is generated using laser-shaping of the electron beam at the photocathode*. The electron bunch is then delayed relative to the pulse by a magnetic chicane, allowing the radiation to slip onto a fresh slice of the bunch, which amplifies the ESASE pulse in the second cascade stage. Angular streaking** characterizes the experimental pulse durations as sub-femtosecond at ~465 eV in the experiment. * Zhang, Z. et al. New J. Phys. 22 (2020) ** Li, S. et al. Optics Express 26.4 (2018): 4531-4547. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT044 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022 | ||
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| TUPOTK063 | CERN Linac4 Chopper Dump: Operational Experience and Future Upgrades | linac, operation, site, radiation | 1370 |
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| The Chopper Dump in the Linac4 accelerator at CERN is a beam-intercepting device responsible for the absorption of the 3 MeV H− ion beam produced by the Linac4 source and deflected upstream by an electromagnetic chopper. It allows a portion of the beam, which would otherwise fall into the unstable region of the radiofrequency buckets in the Proton Synchrotron Booster, to be dumped at low energy with minimal induced radiation. It may also be used to absorb the entire beam. With peak currents of 25 to 45 mA and shallow penetration, this results in large deposited energy densities, thermal gradients and mechanical stresses. Additional constraints arise from geometric integration, vacuum and radiation protection requirements. Material selection, beam-matter interaction studies and thermo-structural analyses are important aspects of the design process. The Chopper Dump underwent modification in 2019 following observed material degradation in the original version of the device. The experience gained, modifications made and observations noted since then are detailed herein. Against this background, the design and analysis of an upgraded device, intended to cope with future operational conditions, is outlined and discussed. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK063 | ||
| About • | Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 26 June 2022 | ||
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| WEPOTK011 | High Intensity Studies in the CERN Proton Synchrotron Booster | resonance, injection, operation, proton | 2056 |
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| After the successful implementation of the LHC Injectors Upgrade (LIU) project, studies were conducted in the CERN Proton Synchrotron Booster (PSB) in order to assess the intensity reach with the increased beam brightness. The studies focused on the high intensity beams delivered to the PSB users, both at 1.4 and 2 GeV. In addition, possible intensity limitations in view of the Physics Beyond Colliders (PBC) Study were investigated. To this end, various machine configurations were tested including different resonance compensation schemes and chromaticity settings in correlation with the longitudinal parameters. This paper summarizes the results obtained since the machine recommissioning. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK011 | ||
| About • | Received ※ 05 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 19 June 2022 | ||
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| THPOMS035 | First Production of Astatine-211 at Crocker Nuclear Laboratory at UC Davis | target, cyclotron, proton, isotope-production | 3038 |
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Funding: This work partially supported by the US DOE under contract DE-SC0020407 There is a great deal of interest in the medical community in the use of the alpha-emitter At-211 as a therapeutic isotope. Among other things, its 7.2 hour half life is long enough to allow for recovery and labeling, but short enough to avoid long term activity in patients. Unfortunately, the only practical technique for its production is to bombard a Bi-209 target with a ~29 MeV alpha beam, so it is not accessible to commercial isotope production facilities, which all use fixed energy proton beams. The US Department of Energy is therefore supporting the development of a "University Isotope Network" (UIN) to satisfy this need. As part of this effort, we have developed an At-211 production facility using the variable-energy, multi-species cyclotron at Crocker Nuclear Lab the University of California, Davis. This effort relies on a beam probe which has been modified to serve as an internal Bi-209 target, to avoid problems with alpha particle extraction efficiency. This poster will data on the first production and recovery of At-211 using this system. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS035 | ||
| About • | Received ※ 09 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 03 July 2022 | ||
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