I.D. Kittelmann, R.A. Baron, E.C. Bergman, E.M. Donegani, V. Grishin, H. Hassanzadegan, H. Kocevar, N. Milas, R. Miyamoto, M. Mohammednezhad, F. Nilen, D. Noll, K.E. Rosengren, T.J. Shea, R. Tarkeshian, C.A. Thomas
ESS, Lund, Sweden
Once constructed, the European Spallation Source (ESS) will be a 5MW pulsed neutron source based on a 2 GeV proton linac delivering 2.86 ms long pulses at a 14 Hz repetition rate. This paper focuses on the beam instrumentation performance during the recent linac beam commissioning up to drift tube linac (DTL) tank 4 with 74 MeV output energy. Instrumentation and measurement results will be presented for beam parameters such as current, position, energy, emittance and beam loss. Proposal by Peter, same proposal as ID 1283 by Wim. Alternative speaker Cyrille Thomas (ESS).
A.S. Fisher, N. Balakrishnan, G.W. Brown, E.P. Chin, W.G. Cobau, J.E. Dusatko, B.T. Jacobson, S. Kwon, J.A. Mock, J. Park, J. Pigula, E. Rodriguez, J.I.D. Rudolph, D. Sanchez, L. Sapozhnikov, J.J. Welch
SLAC, Menlo Park, California, USA
A 4-GeV superconducting linac has been added to the LCLS x-ray FEL facility at SLAC. Its 120-kW, 1-MHz beam requires new beam-loss monitors (BLMs) for radiation protection, machine protection, and diagnostics. Long radiation-hard optical fibres span the full 4 km from the electron gun of the SC linac to the final beam dump. Diamond detectors at anticipated loss points provide local protection. Detector signals are continuously integrated with a 500-ms time constant and compared to a loss threshold. If crossed, the beam is halted within 0.1 ms. Commissioning began in March 2022 with the 100-MeV injector and with RF processing of the cryomodules. At IBIC 2022 last September, we presented commissioning results from the injector BLMs. In October, the beam passed through the full linac and the bypass transport line above the LCLS copper linac, stopping at an intermediate dump. In August it continued through the soft x-ray undulator and achieved first lasing. Here we present BLM commissioning at energies up to 4 GeV and rates up to 100 kHz. We discuss measurements and software using the fast diagnostic-waveform output to localize beam losses and to detect wire-scanner signals.
H. Hassanzadegan, R.A. Baron, S. Gabourin, H. Kocevar, M. Mohammednezhad, J.F.J. Murari, S. Pavinato, K.E. Rosengren, T.J. Shea, R. Zeng
ESS, Lund, Sweden
K. Czuba, P.K. Jatczak
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
The ESS BCM system is not only used for beam measurement but it also plays an important role for machine protection particularly in the normal-conducting part of the linac. During the previous beam commissionings to the MEBT and DTL1 FCs and before the cavities were fully conditioned, RF breakdowns and other types of discharges in the cavities had a major impact on beam availability due to the Fast machine protection functions of the BCM. Following an investigation on the root cause of the beam trips, the configuration of the machine protection functions was modified to improve beam availability in the more recent beam commissioning to the DTL4 FC. In addition to this, some optimizations were made in the BCM system to improve beam measurement, and a few more functions were added based on new requirements. This paper reports on these improvements and the results obtained during the beam commissioning through the DTL4.
Funding:This research used resources of the Advanced Photon Source, operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Large accelerator systems typically include many individually powered electromagnets. An important activity prior to commissioning with beam is verifying that the polarity of the installed magnets matches the design lattice. In the present work, we motivate the measurement of magnet polarity in a manner that is electrically safe, by measuring the magnetic remanence of iron yokes of normal conducting electromagnets. This has been used to confirm the polarities of iron-dominated dipole and quadrupole electromagnets at the Linac Extension Area at the Advanced Photon Source.
K.P. Wootton, W. Berg, M. Borland, A.R. Brill, J.M. Byrd, S. Chitra, J.T. Collins, J.C. Dooling, J.N. Edwards, L. Erwin, G.I. Fystro, T. Grabinski, M.J. Henry, E.E. Heyeck, J.E. Hoyt, R.T. Keane, S.H. Lee, J. Lenner, I. Lobach, A.H. Lumpkin, A. Puttkammer, V. Sajaev, N. Sereno, Y. Sun, J. Wang, S.G. Wang, A. Zholents
ANL, Lemont, Illinois, USA
Funding:This research used resources of the Advanced Photon Source, operated for the U.S. Department of Energy Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. The Linac Extension Area has been developed into a beamline area for testing accelerator components and techniques. Beginning commissioning activities in February 2023, we have delivered the first electron beam to the Linac Extension Area at the Advanced Photon Source at 425 MeV. In the present work, we outline the stages of re-commissioning the electron beamline. We summarise measurements of the electron beam transport through the accelerator. We outline scenarios used to verify the adequacy of radiation shielding of the beamline, and measured shielding performance.
C. Bianchini Mattison, K.H. Kim, P. Krejcik, M. Weaver, S. Zelazny
SLAC, Menlo Park, California, USA
The new timing system for the LCLS-II SC linac and FEL meets the challenging requirements for delivering multiple interleaved timing patterns to a number of different destinations at rates up to 1 MHz. The timing patterns also carry information on bunch charge and beam energy to prevent inadvertent selection of beam dumps beyond their rated beam power. Beamline instruments are equipped with a timing receiver that performs bunch-by-bunch synchronous data acquisition based on the timing pattern for that location. Data is buffered in on-board memory for up to 106 machine pulses (1 second at 1 MHz). The large data volume can be locally processed and and analysed before transmission to clients on the network. Commissioning and experience with the new system will be presented.
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