T.V. Gorlov, J.A. Holmes
ORNL, Oak Ridge, Tennessee, USA
A self-consistent beam maintains linear space charge forces under any linear transport, even with the inclusion of space charge in the dynamics. Simulation indicates that it is possible to approximate certain self-consistent distributions in a ring with the use of phase space painting. We focus on the so-called Danilov distribution, which is a uniform density, rotating, elliptical distribution in the transverse plane and a coasting beam in the longitudinal plane. Painting the beam requires measurement and control of the orbit at the injection point, and measuring the beam requires re- construction of the four-dimensional (4D) transverse phase space. We discuss efforts to meet these requirements in the Spallation Neutron Source (SNS) ring.
M. Patecki, D. Kikoła
Warsaw University of Technology, Warsaw, Poland
A.S. Fomin, D. Mirarchi, S. Redaelli
CERN, Geneva, Switzerland
Funding:This project has received funding from the European Union’s Horizon 2020 research and innovation programme. The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) is the world largest and most powerful particle accelerator colliding beams of protons and lead ions at energies up to 7 TeV and 2.76 TeV, respectively. ALICE is one of the detector experiments optimised for heavy-ion collisions. A fixed-target experiment in ALICE is considered to collide a portion of the beam halo split by means of a bent crystal with an internal target placed a few meters upstream of the detector. Fixed-target collisions offer many physics opportunities related to hadronic matter and the quark-gluon plasma to extend the research potential of the CERN accelerator complex. This paper summarises our progress in preparing the fixed-target layout consisting of crystal assemblies, a target and downstream absorbers. We discuss the conceptual integration of these elements within the LHC ring, impact on ring losses, conditions for a parasitic operation and expected performance in terms of particle flux on target.
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Funding:This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The SNS accelerator consist of a 1 GeV H⁻ linac and an accumulator ring producing a 1.4 MW pulsed proton beam which drives a spallation neutron source. The Proton Power Upgrade project will double the power capability from 1.4 to 2.8 MW by increasing the linac energy 30% and the beam current about 50%. Equipment upgrades include new superconducting RF cryomodules and supporting RF equipment, upgraded ring equipment, and upgraded high power target systems. An important aspect of the upgrade is a gradual power ramp-up starting in 2022 in which new equipment is installed during maintenance outages as it arrives.
Funding:SNS is managed by UT-Battelle, LLC, under contract DE- AC05-00OR22725 for the U.S. Department of Energy. The Spallation Neutron Source (SNS) uses 300-400μ g/cm2 nanocrystalline diamond foils grown in-house at the Center for Nanophase Materials Sciences to facilitate charge exchange injection (CEI) from the 1 GeV H⁻ linac into the 248~m circumference accumulation ring. These foils have performed exceptionally well with lifetimes of thousands of MW·hrs. This contribution shares some experience with the operation of these foils during 1.4 MW operation, and discusses current operational concerns including injection related losses, foil conditioning, deformation, and sublimation due to high temperatures. The implications for the SNS Proton Power Upgrade are also discussed.
V. Kain, N. Madysa, P.K. Skowroński, I. Vojskovic
CERN, Geneva, Switzerland
N. Bruchon
University of Trieste, Trieste, Italy
S. Hirlaender, G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta
The CERN H⁻ linear accelerator, LINAC4, served as a test bed for advanced algorithms during the CERN Long Shutdown 2 in the years 2019/20. One of the main goals was to show that reinforcement learning with all its benefits can be used as a replacement for numerical optimization and as a complement to classical control in the accelerator control context. Many of the algorithms used were prepared beforehand at the electron line of the AWAKE facility to make the best use of the limited time available at LINAC4. An overview of the algorithms and concepts tested at LINAC4 and AWAKE will be given and the results discussed.
M.Y. Huang, S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China
Funding:Work supported by National Natural Science Foundation of China (Project Nos. 12075134 and U1832210 ) In this paper, firstly, the beam commissioning of the injection system for CSNS/RCS will be studied, including: timing adjustment of the injection pulse powers, injection beam parameter matching, calibration of the injection painting bumps, measurement of the painting distribution, injection method adjustment, application of the main stripping foil, optimization of the injection beam loss and radiation dose, etc. Secondly, the painting methods for the CSNS/RCS will be studied, including: the fixed-point injection method, anti-correlated painting method and correlated painting method. The results of the beam commissioning will be compared with the simulation results. Combining with other precise optimizations, the beam power on the target has successfully reached the design value of 100kW and the stable operation of the accelerator has been achieved.
T. Nishi, M. Fujimaki, N. Fukunishi, H. Imao, O. Kamigaito, T. Nagatomo, N. Sakamoto, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
The performance of RIKEN heavy-ion linac (RILAC) has been upgraded with a new ECR ion source and superconducting linac booster (SRILAC). It is expected to play a major role in the synthesis of super-heavy elements (SHE), development of the technologies for production of medical radioisotopes, and as a powerful injector to RI Beam Factory. In this talk, I will report on the beam delivery for the SHE experiment that started in June 2020, especially on how to adjust the optics based on the measured beam emittance. We would also like to compare the simulated beam acceleration in RILAC with the measured emittance.
