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MOPOST003 BBQ and Doughnut Beams: A Tasty Recipe for Measuring Amplitude Dependence of the Closest Tune Approach coupling, quadrupole, resonance, octupole 42
 
  • E.H. Maclean, F.S. Carlier, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
 
  Beam-based observations and theoretical studies have demonstrated the existence of a significant amplitude dependence of the closest tune approach (ADECTA) in the LHC. This effect has the potential to generate significant distortion of the tune footprint and thus is of interest in regard to Landau damping. Conventionally ADECTA has been studied through saturation of tune separation with action during amplitude-detuning type measurements. In this paper, an alternative measurement technique is proposed and results of initial tests with beam are presented. The novel technique attempts to measure ADECTA by performing a classical closest approach tune scan, using proton beams in the LHC, which have been kicked and allowed to decohere, effectively giving a large action doughnut beam. It is shown that the tune and closest approach of the doughnut beams can be measured using the existing LHC Base-Band tune (BBQ) measurement system, and an amplitude dependence can be observed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST003  
About • Received ※ 08 June 2022 — Revised ※ 20 June 2022 — Accepted ※ 12 July 2022 — Issue date ※ 22 June 2022
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MOPOST030 Proton Irradiation Site for Si-Detectors at the Bonn Isochronous Cyclotron radiation, cyclotron, proton, HOM 130
 
  • D. Sauerland, R. Beck, P.D. Eversheim
    HISKP, Bonn, Germany
  • J. Dingfelder, P. Wolf
    SiLab, Bonn, Germany
 
  The Bonn Isochronous Cyclotron provides proton, deuteron, alpha particle and other light ion beams with a charge-to-mass ratio Q/A of ’ 1/2 and kinetic energies ranging from 7 to 14 MeV per nucleon. At a novel irradiation site, a 14 MeV proton beam with a diameter of a few mm is utilized to homogeneously irradiate silicon detectors, so-called devices under test (DUTs), to perform radiation hardness studies. Homogeneous irradiation is achieved by moving the DUT through the beam in a row-wise scan pattern with constant velocity and a row separation smaller than the beam diameter. During the irradiation procedure, the beam parameters are continuously measured non-destructively using a calibrated, secondary electron emission-based beam monitor, installed at the exit window of the beamline. The diagnostics and the irradiation procedure ensure a homogeneous irradiation with a proton fluence error of smaller than 2 %. In this work, an overview of the accelerator facility is given and the irradiation site with its beam diagnostics is presented in detail.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST030  
About • Received ※ 08 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 07 July 2022  
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MOPOTK059 Implementation of the Vico-Greengard-Ferrando Poisson Solver in Synergia2 simulation, space-charge, beam-beam-effects, framework 600
 
  • C.S. Park
    KUS, Sejong, Republic of Korea
 
  Computation of space charge fields in accelerator simulations is one of the most challenging tasks. The algorithm proposed by Hockney and Eastwood is the fastest method for numerically solving Poisson equations with open boundaries and has been implemented in various accelerator simulation codes. Recently, Vico-Greengard-Ferrando proposed a new hybrid fast algorithm for computing volume potentials. The new algorithm is promising higher accuracy and faster error convergence than that of Hockney-Eastwood. This study presents the implementation of the Vico-Greengard-Ferrando solver in Synergia and shows a comparison of results with these Poisson solvers.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK059  
About • Received ※ 10 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022
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MOPOMS004 Optimizing Activation Recipe with Cs, Te, O for GaAs-Based Photocathodes cathode, electron, vacuum, polarization 628
 
  • J. Bae, M.B. Andorf, I.V. Bazarov, A. Galdi, J.M. Maxson
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • L. Cultrera
    BNL, Upton, New York, USA
 
  Funding: Department of Energy (DOE) DE-SC0021039.
GaAs-based photocathodes are the most popular electron sources for producing highly spin-polarized electron beams in accelerator physics and condensed matter physics. Spin-polarized photoemission requires activation to achieve Negative Electron Affinity (NEA). Conventional NEA surfaces such as CS-O/NF3 are extremely vacuum sensitive, and this results in rapid QE degradation. In this work, we activated GaAs with various recipes using Cs, Te, and oxygen. We demonstrate NEA activation on GaAs surfaces. Among Cs-Te activated samples, the oxidized sample showed the highest QE and longest lifetime at 780 nm.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS004  
About • Received ※ 04 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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MOPOMS027 Synthesis of First Caesium Telluride Photocathode at ASTeC Using Sequential and Co-Deposition Method cathode, target, FEL, electron 695
 
  • R. Valizadeh, A.N. Hannah
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • V.R. Dhanak
    The University of Liverpool, Liverpool, United Kingdom
  • S. Lederer
    DESY, Hamburg, Germany
 
  Caesium Telluride (Cs2Te) photocathodes, are the elec-tron source of choice, by many global accelerators such as European XFEL, FLASH and AWA. It offers high quantum efficiency and reasonable operational lifetime with lower vacuum requirements than multi-alkali photocathodes. In this paper, we report on the first synthesised CsxTe photocathodes at ASTeC, using both sequential and co-deposition of Te and Cs on Mo substrate. Te deposition is carried out using ion beam deposition whilst the Cs is deposited using a SAES getter alkali. The ion beam deposition of Te provides a high degree of control to give a dense, smooth layer with a reproducible film thickness. The chemical state with respect to film composition of the deposited CsxTe is determined with in-situ XPS anal-yses. The films exhibit a quantum efficiency between 7.5 to 9 % at 266 nm wavelength.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS027  
About • Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUOZGD1 Need for Portable Accelerators in Cultural Heritage proton, rfq, linac, radio-frequency-quadrupole 808
 
  • T.K. Charles
    The University of Liverpool, Liverpool, United Kingdom
  • R.M. Bodenstein, A. Castilla
    JLab, Newport News, Virginia, USA
 
  Ion Beam Accelerators (IBA) centres have provided researchers with powerful techniques to analyse objects of cultural significance in a non-destructive and non-invasive manner. However, in some cases it is not feasible to remove an object from the field or museum and transport it to the laboratory. In this contributed talk, we present as a manner of a short review, examples of the benefits provided from these techniques in the study of material culture and discuss the initial steps to consider when investigating the feasibility of a compact accelerator that can be taken to sites of cultural significance for PIXE analysis. In particular, we consider the application of a compact, robust 2 MeV proton accelerator that can be taken into the field to perform PIXE measurements on rock art. We detail the main challenges and considerations for such a device.  
slides icon Slides TUOZGD1 [7.603 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUOZGD1  
About • Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022
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TUPOPT069 Preparation and Characterization of BTO-BFO Multiferroic Ceramics as Electrical Controllable Fast Phase Shifting Component controls, experiment, factory, radiation 1178
 
  • N.W. Martirosyan, A. Grigoryan, Kh.Gh. Kirakosyan, V. Sahakyan, A. Sargsyan
    CANDLE SRI, Yerevan, Armenia
  • A. Grigoryan
    YSU, Yerevan, Armenia
  • G.S. Karoyan, R.H. Khazaryan, M.M. Mkrtchian, T. Vandunts
    NPUA, Yerevan, Armenia
 
  A rich variety of dielectric, optical, acoustic/piezoelectric, ferromagnetic properties of ferroelectric and multiferroic composite materials open a new perspective for the development of modern accelerators with new principle of electron acceleration and control system. These properties may be controlled by external electric fields. In particular, the production of electric field controlling ultrafast facilities for 0.7-20 GHz RF phase shifting and amplitude modulation where a very short response time of <10 nsec is required . A Self-propagating High-temperature Synthesis (SHS) technology for obtaining ceramic materials, based on (1-x)BiFeO3-xBaTiO3 compositions with various dopant (MgO, MnO, etc.), has been developed. The general parameters of the SHS process (temperature and propagation velocity of the combustion front) are measured. The dependences of microstructure (grain size, density, and porosity), as well as electro physical properties of the sintered samples on compaction and sintering thermodynamic variables, such as the pressing pressure and duration, sintering temperature, sintering duration and atmosphere, heating and cooling rates, are experimentally investigated.
* https://doi.org/10.3390/coatings11010066
** Appl. Phys. Let., V.101, p. 232903-5, 2012
*** A. Kanareykin & et al. FERROELECTRIC BASED HIGH POWER TUNER FOR L-BAND ACCELERATOR APPLICATIONS. IPAC2013
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT069  
About • Received ※ 31 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 12 June 2022
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TUPOTK013 PEALD SIS Studies for SRF Cavities cavity, SRF, plasma, niobium 1222
 
  • I. González Díaz-Palacio, R.H. Blick, A. Stierle, R. Zierold
    University of Hamburg, Hamburg, Germany
  • W. Hillert, M. Wenskat
    University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
  • A. Jeromin
    DESY Nanolab, FS-NL, Hamburg, Germany
  • T.F. Keller, N. Krupka, M. Wenskat
    DESY, Hamburg, Germany
 
  Recent technological advances and material treatments have pushed Nb SRF cavities to their maximum RF performance. A novel approach for overcoming this limitation, which takes advantage of RF field only penetrates into the superconductor at a certain distance called London penetration depth, is nano-structuring multilayers with PEALD (plasma-enhanced atomic layer deposition). SIS (superconductor-insulator-superconductor) multilayers provide magnetic screening of the bulk Nb cavity, increasing the field at which the vortex penetration starts, and higher quality factor. ALD is closely related to chemical vapor deposition and bases on sequential self-limit gas-solid surface reactions facilitating conformal coatings with sub-nm precision even on complex substrates such as the interior of a cavity. As a preliminary study for SIS SRF cavities, we investigated the AlN-NbTiN/NbN multilayers grown by PEALD. Different compositions, thicknesses, and post-deposition thermal treatments have been investigated. The characterization results of superconducting properties, elemental composition, crystallinity, and cross-section are shown in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK013  
About • Received ※ 09 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022
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TUPOTK018 Combined In-Situ QEXAFS and XRD Investigations on Nb-Treatments in N2 Gas Atmospheres at Elevated Temperatures vacuum, cavity, niobium, SRF 1238
 
  • P. Rothweiler, F. Eckelt, D. Lützenkirchen-Hecht, S. Paripsa, L. Voß
    University of Wuppertal, Wuppertal, Germany
 
  Funding: We gratefully acknowledge financial support by the German Federal Ministry of Education and Research (BMBF) under project No. 05H18PXRB1.
Thin polycrystalline Nb metal foils were treated in N2 gas atmospheres at elevated temperatures of 900 °C up to 1200 °C. A combination of transmission mode Quick X-ray absorption spectroscopy (QEXAFS) at the Nb-K-edge and X-ray diffraction (XRD) used in parallel were used to investigate changes in the atomic short and long-range structure of the bulk Nb-material in-situ. A dedicated high-vacuum heating cell with a base pressure of 10-6 mbar was used to perform the heat treatments under vacuum and nitrogen gas atmosphere. The treatments typically included (i) a preheating at 900 °C under high-vacuum, (ii) a treatment in 3 mbar nitrogen gas at the desired temperature and (iii) a cooldown to room temperature under vacuum conditions. The QEXAFS and XRD data were collected in parallel during the entire process with a time resolution of 4 s. While the samples treated at 900 °C show the typical N-uptake to the octahedral interstitial sites, the samples treated at higher temperatures show the growth of distinct niobium nitride phases. The results will be discussed in more details during the conference.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK018  
About • Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 18 June 2022
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TUPOTK022 INFN-LASA for the Fermilab PIP-II cavity, SRF, controls, linac 1249
 
  • R. Paparella, M. Bertucci, M. Bonezzi, A. Bosotti, D. Cardelli, A. D’Ambros, E. Del Core, A.T. Grimaldi, L. Monaco, D. Sertore, G.M. Zaggia
    INFN/LASA, Segrate (MI), Italy
  • C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  The status of INFN-LASA contribution to the PIP-II project at Fermilab is reported in this paper. Experimental results and ongoing activities on prototypes are summarized together with the development of related testing infrastructures. The series production of the 38 5-cell, beta 0.61 cavities designed by INFN-LASA for the LB650 section of the PIP-II linac recently commenced, the status of major procurements and associated activities is here below presented. All cavities will be produced and surface treated in industry to reach the unprecedented performances required, qualified through vertical cold test at qualified infrastructures and delivered as linac-ready at the string assembly site.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK022  
About • Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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TUPOTK031 A First 6 GHz Cavity Deposition with B1 Superconducting Thin Film at ASTeC cavity, SRF, target, controls 1279
 
  • R. Valizadeh, A.N. Hannah, O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • E. Chyhyrynets, V.A. Garcia Diaz, C. Pira
    INFN/LNL, Legnaro (PD), Italy
  • V.R. Dhanak
    The University of Liverpool, Liverpool, United Kingdom
  • O.B. Malyshev
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G.B.G. Stenning
    STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
 
  Nb3Sn, NbTiN and NbN are superconductors with critical temperatures of 18.3, 12.6-17 and 11.6-17.5 K, respectively, these are higher than that of Nb at 9.3 K. Hence, at 4 K, they have an RF resistance, an order of magnitude lower than that of Nb, which leads to quality factors above those of Nb. In recent years, there has been an extensive effort converting Nb cavities into Nb3Sn. Alloying the top inner layer of the cavity using Sn diffusion at a high temperature has had some degree of success, however, the reproducibility remains a major hindering and limiting factor. In this study, we report on the PVD deposition of NbTiN inside a 6 GHz cavity, using an external magnetic coil configuration. The deposition is done at an elevated temperature of about 650 C. We report on the superconducting properties, film structure and its stoichiometry and surface chemical state. The films have been characterised with SEM, XRD, XPS, EDS and SQUID magnetometer.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK031  
About • Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUPOTK033 First RF Measurements of Planar SRF Thin Films with a High Throughput Test Facility at Daresbury Laboratory cavity, SRF, MMI, pick-up 1283
 
  • D.J. Seal, G. Burt, P. Goudket, O.B. Malyshev, B.S. Sian, R. Valizadeh
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • G. Burt, D.J. Seal, B.S. Sian
    Lancaster University, Lancaster, United Kingdom
  • P. Goudket, O.B. Malyshev, R. Valizadeh
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Goudket
    ESS, Lund, Sweden
  • H.S. Marks
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
 
  The research on superconducting thin films for future radio frequency (RF) cavities requires measuring the RF properties of these films. However, coating and testing thin films on full-sized cavities is both challenging and timeconsuming. As a result, films are typically deposited on small, flat samples and characterised using a test cavity. At Daresbury Laboratory, a facility for testing 10 cm diameter samples has recently been commissioned. The cavity uses RF chokes to allow physical and thermal separation between itself and the sample under test. The facility allows for surface resistance measurements at a resonant frequency of 7.8 GHz, at temperatures down to 4 K, maximum RF power of 1 W and peak magnetic fields of a few mT. The main advantage of this system is the simple sample mounting procedure due to no physical welding between the sample and test cavity. This allows for a fast turnaround time of two to three days between samples. As such, this system can be used to quickly identify which samples are performing well under RF and should require further testing at higher gradient. Details of recent upgrades to this facility, together with measurements of both bulk niobium and thin film samples, will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK033  
About • Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 02 July 2022
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TUPOTK036 Study of Chemical Treatments to Optimize Niobium-3 Tin Growth in the Nucleation Phase niobium, cavity, SRF, radio-frequency 1295
 
  • L. Shpani, S.G. Arnold, G. Gaitan, M. Liepe, Z. Sun
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • T. Arias, M.M. Kelley, N. Sitaraman
    Cornell University, Ithaca, New York, USA
 
  Funding: This research is funded by the National Science Foundation under Grant No. PHY-1549132, the Center for Bright Beams.
Niobium-3 Tin (Nb3Sn) is a high-potential material for next-generation Superconducting Radiofrequency (SRF) cavities in particle accelerators. The most promising growth method to date is based on vapor diffusion of tin into a niobium substrate with nucleating agent Tin Chloride (SnCl2). Still, the current vapor diffusion recipe has significant room for realizing further performance improvement. We are investigating how different chemical treatments on the niobium substrate before coating influence the growth of a smooth and uniform Nb3Sn layer. More specifically, this study focuses on the interaction between the SnCl2 nucleating agent and the niobium surface oxides. We compare the effect of different chemical treatments with different pH values on the tin droplet distribution on niobium after the nucleation stage of coating. We also look at the effect that the nucleation temperature has on the smoothness and uniformity of the tin distribution, with the ultimate goal of optimizing the recipe to coat smooth Nb3Sn cavities.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK036  
About • Received ※ 12 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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TUPOTK063 CERN Linac4 Chopper Dump: Operational Experience and Future Upgrades linac, operation, ISOL, radiation 1370
 
  • C.J. Sharp, P. Andreu Muñoz, M. Calviani, G. Costa, L.S. Esposito, R. Franqueira Ximenes, D. Grenier, E. Grenier-Boley, J.R. Hunt, A.M. Krainer, C.Y. Mucher, C. Torregrosa
    CERN, Meyrin, Switzerland
 
  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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WEPOST040 Comparing Methods of Recovering Gamma Energy Distributions from PEDRO Spectrometer Responses photon, electron, positron, scattering 1784
 
  • M.H. Oruganti, B. Naranjo, J.B. Rosenzweig, M. Yadav
    UCLA, Los Angeles, California, USA
 
  To calculate the energy levels of the photons emitted from high-energy particle interactions, the new pair spectrometer (PEDRO) channels the photons through several Beryllium nuclear fields to produce electron-positron pairs through the nuclear field interaction. This project compared several methods of reconstruction and determined which best predicts original energy distributions based on simulated spectra. These methods included using Maximum Likelihood Estimation, Machine Learning, and directly analyzing a response matrix that modeled PEDRO’s response to any photon energy distribution. We report that performing the direct analysis, also known as QR decomposition, on a PEDRO-generated spectrum provides by far the most accurate calculation of the spectrum’s original energy distribution. These methods were tested against results from experimental cases, including Nonlinear Compton Scattering and Filamentation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST040  
About • Received ※ 15 June 2022 — Revised ※ 01 July 2022 — Accepted ※ 08 July 2022 — Issue date ※ 08 July 2022
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WEPOPT017 First Optics Design for a Transverse Monochromatic Scheme for the Direct S-Channel Higgs Production at FCC-ee Collider optics, collider, positron, luminosity 1878
 
  • H.P. Jiang
    Harbin Institute of Technology (HIT) , Harbin, People’s Republic of China
  • A. Faus-Golfe, Z.D. Zhang
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
  • K. Oide
    KEK, Ibaraki, Japan
  • Z.D. Zhang
    IHEP, Beijing, People’s Republic of China
  • Z.D. Zhang
    UCAS, Beijing, People’s Republic of China
  • F. Zimmermann
    CERN, Meyrin, Switzerland
 
  The FCC-ee collider baseline foresees four different energy operation modes: Z, WW, H(ZH) and ttbar. An optional fifth mode, called s-channel Higgs production mode, could allow the measurement of the electron Yukawa coupling, in dedicated runs at 125 GeV centre-of-mass energy, provided that the centre-of-mass energy spread, can be reduced by at least an order of magnitude (5-10 MeV). The use of a special collision technique: a monochromatization scheme is one way to accomplish it. There are several methods to implement a monochromatization scheme. One method, named transverse monochromatization scheme, consists of introducing a dispersion different from zero but opposite sign for the two colliding beams at the Interaction Point (IP); In this paper we will report about the first attempt to design a new optics to implement a transverse monochromatic scheme for the FCC-ee Higgs production totally compatible with the standard mode of operation without dispersion at the IP.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT017  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 27 June 2022
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WEPOTK010 The Second Long Shutdown of the LHC and Its Injectors: Feedback from the Accelerator Coordination and Engineering Group operation, experiment, GUI, database 2052
 
  • A.-L. Perrot, M. Bernardini, S. Chemli, J.-P. Corso, J. Coupard, F.B. Dos Santos Pedrosa, J. Etheridge, K. Foraz, S. Grillot, J.M. Jimenez, B. Nicquevert, S. Petit, J.Ph.G.L. Tock, E. Vergara Fernandez
    CERN, Meyrin, Switzerland
 
  The operation of the Large Hadron Collider (LHC) at CERN started in September 2008. Every 5 or 6 years, Long Shutdowns (LS) are programmed to execute time-intensive ordinary and extra-ordinary maintenance of the LHC and its injectors. The second LS (LS2) started in December 2018 and was completed end 2020 for the injectors and early 2022 for the LHC. A huge number of maintenance, consolidation and upgrade activities, especially the upgrade of the injectors complex, were performed with challenges at various levels, from technical, to organizational and managerial. This paper presents the applied methodology put in place by the Accelerator Coordination & Engineering (EN-ACE) Group, in charge of the technical coordination of the activities for the interventions and changes to the LHC and its injectors, to ensure that the installation activities are performed safely, meeting the required high level of quality, while optimizing the schedule. It highlights key points of success and lessons learnt in terms of general coordination, quality assurance, configuration and layout management, spatial integration, planning and scheduling, operational safety, logistics and worksite coordination  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK010  
About • Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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THPOST038 On-Site Transport and Handling Tests of Cryomodules for the European Spallation Source cryomodule, cavity, diagnostics, SRF 2527
 
  • F. Schlander, A. Bignami, N. Gazis
    ESS, Lund, Sweden
 
  The cryomodules for the superconducting Linac of the European Spallation Source ’ ESS are now arriving in a steady stream and the long-distance transport requirements are well understood. For the on-site transportation, handling and storage, several challenges have risen, including the intermediate storage of cryomodules before testing and/or installation. In comparison to the long-distance transports, the cryomodule on-site transports and respective handling until installation take place with specialised and limited transport protection. This requires additional measures and tests of those handling steps with extended diagnostics, to make sure that handling and transport refrains from damages on the last mile. Those handling procedures and executed tests will be described in this contribution.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST038  
About • Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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THPOPT026 Assembly and Characterization of Low-Energy Electron Transverse Momentum Measurement Device (TRAMM) at INFN LASA cathode, electron, emittance, laser 2630
 
  • D. Sertore, M. Bertucci, A. Bosotti, D. Giove, L. Monaco, R. Paparella
    INFN/LASA, Segrate (MI), Italy
  • G. Guerini Rocco, C. Pagani
    Università degli Studi di Milano & INFN, Segrate, Italy
 
  In the framework of high-brightness electron beam generation, thermal emittance is nowadays a key parameter. While alkali tellurides are extensively used in advanced electron sources, alkali antimonides photocathodes demonstrated high QE in the visible, thus making feasible CW operations for RF-based photoinjectors. The INFN LASA laboratory in Milan is fully equipped with dedicated production systems for photocathode preparation and optical setup for QE evaluation. In this paper, we describe a newly designed device dedicated to electron transverse momentum measurement (TRAMM). It will be connected to the main production chambers and will serve as an "emittance monitoring" system during photocathode growth. From the design phase, through the parameter estimate, assembly of the components, to the installation and first measurements, we describe the status of this project and its future developments.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT026  
About • Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 07 July 2022
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THPOTK029 Role of Surface Chemistry in Conditioning of Materials in Particle Accelerators electron, radiation, ECR, multipactoring 2829
 
  • G. Sattonnay, S. Bilgen, S. Della Negra, D. Longuevergne, B. Mercier, I. Ribaud
    Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
 
  For the vacuum scientists and the accelerator community, finding solutions to mitigate pressure rises induced by electron, photon and ion desorption and beam instabilities induced by ion and electron clouds is a major issue. Along the time, changes in the surface chemistry of vacuum chambers are observed during beam operations in particle accelerators, leading to modifications of: outgassing rates, stimulated desorption processes and a decrease of secondary emission yields (SEY). To understand the role of the surface chemistry of air exposed materials in the electron conditioning process, typical air exposed materials used in particle accelerators : thin film coatings (NEG and TiN), copper (and its oxides Cu2O and CuO) and Niobium were conditioned by low energy electron irradiation for a better understanding of Ecloud effect. First, SEY was measured to understand the changes of surface conditioning upon particle irradiation; then, surface chemistry evolution after electron irradiation was investigated by both XPS and TOF-SIMS analyses using the ANDROMEDE facility at IJCLab. Finally, the relationship between the surface chemistry and the conditioning phenomenon will be discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK029  
About • Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 05 July 2022
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THPOTK036 Determination of Pumping and Dynamic Vacuum Properties of Conductive Quaternary Alloy of TiZrVAg Non-Evaporable Getter. vacuum, photon, electron, experiment 2843
 
  • R. Valizadeh, A.N. Hannah, O.B. Malyshev
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • G.Y. Hsiung
    NSRRC, Hsinchu, Taiwan
  • J.M. O’Callaghan Castella
    Universitat Politécnica de Catalunya, Barcelona, Spain
  • M. Pont, N.D. Tagdulang
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
 
  Non Evaporable Getter (NEG) coating has been employed extensively in the particle accelerator especially where the vacuum conductance of the vessel is severely restricted and ultra-high vacuum condition is required. NEG coating will significantly reduce the outgassing rate and provides active pumping surface for H2, CO and CO2. In addition, it has been proven that NEG coated surfaces have a very low secondary electron yield, as well as low photon and electron stimulated desorption yields. However, the existing NEG film increases the RF surface resistance of the beam pipe. In order to increase NEG coating conductivity, at ASTeC, in the past several years, the alternative NEG com-position have been studied by adding more conductive element such as Cu, Au, Al and Ag. In this study, we report on the photon stimulated desorption, activation temperature and surface resistance from room temperature to cryogenic temperature for a new NEG quaternary alloy of TiVZrAg as function of the film composition.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK036  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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THPOMS023 Design of the 590 MeV Proton Beamline for the Proposed TATTOOS Isotope Production Target at PSI proton, target, simulation, neutron 3000
 
  • M. Hartmann, D.C. Kiselev, D. Reggiani, M. Seidel, J. Snuverink, H. Zhang
    PSI, Villigen PSI, Switzerland
 
  IMPACT (Isotope and Muon Production with Advanced Cyclotron and Target Technologies) is a proposed initiative envisaged for the high-intensity proton accelerator facility (HIPA) at the Paul Scherrer Institute (PSI). As part of IMPACT, a radioisotope target station, TATTOOS (Targeted Alpha Tumour Therapy and Other Oncological Solutions) will allow the production of terbium radionuclides for therapeutic and diagnostic purposes. The proposed TATTOOS beamline and target will be located near the UCN (Ultra Cold Neutron source) target area, branching off from the main UCN beamline. In particular, the beamline is intended to operate at a beam intensity of 100 µA, requiring a continuous splitting of the main beam via an electrostatic splitter. Realistic beam loss simulations to verify safe operation have been performed and optimised using Beam Delivery Simulation (BDSIM), a Geant4 based tool enabling the simulation of beam transportation through magnets and particle passage through the accelerator. In this study, beam profiles, beam transmission and power deposits are generated and studied.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS023  
About • Received ※ 18 May 2022 — Revised ※ 31 May 2022 — Accepted ※ 16 June 2022 — Issue date ※ 04 July 2022
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THPOMS038 Spallation Target Optimization for ADS by Monte Carlo Codes target, neutron, proton, experiment 3049
 
  • MumyapanM. Mumyapan, J.-S. Chai, M. Ghergherehchi, D.H. Ha, H. Namgoong
    SKKU, Suwon, Republic of Korea
 
  Accelerator Driven Systems are advanced systems for the use of Thorium as fuel, aiming to reduce nuclear waste through transmutation. The spallation target, which is responsible for producing neutrons, is one of the main parts of the ADS system. In this research, neutronic parameters of spallation targets consisting of several materials LBE, Mercury, Lead, Mercury on the cylindrical, box, and conic shapes using Monte Carlo codes (FLUKA, PHITS, MCNPX) was investigated. Energy Deposition and spallation neutron yield of spallation target with different shapes and dimensions have been calculated to optimization of the target. According to the results, the neutron yield values from MCNPX and PHITS are similar and it’s close to the experimental result. On the other hand, the error rate of the values in FLUKA is higher.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS038  
About • Received ※ 16 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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THPOMS043 Mu*STAR: Superconducting Accelerator Driven Subcritical Molten Salt Nuclear Power Plants neutron, target, operation, extraction 3067
 
  • R.P. Johnson, R.J. Abrams, M.A. Cummings, J.D. Lobo, T.J. Roberts
    Muons, Inc, Illinois, USA
 
  The Mu*STAR Nuclear Power Plant (NPP) is a transformational and disruptive concept using advances in superconducting accelerator technology to burn spent nuclear fuel (SNF) to close the fuel cycle and to eliminate need for uranium enrichment. One linac drives multiple Mu*STAR Small Modular Reactors (SMR) using subcritical molten salt fueled reactors with an internal spallation neutron target. Neutrons initiate fission chains that die out in the subcritical core. That means intrinsic immunity to criticality accidents. This new way to make nuclear energy employs continuous online removal of all fission products from molten salt fuel volatiles removed by helium purge gas. This reduces chance of accidental release. Non-volatiles removed by vortex separators, allowing complete burning of SNF.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS043  
About • Received ※ 09 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022
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