FRIB, East Lansing, Michigan, USA
The Facility for Rare Isotope Beams (FRIB) includes a continuous wave superconducting linear accelerator designed to deliver 400 kW ion beams with energies above 200 MeV/u. The beam commissioning of the first three cryomodules took place in the summer of 2018. A temporary diagnostic station installed after the first three cryomodules included a Silicon Detector (SiD) to measure absolute energy and bunch shape of 40Ar and 86Kr beams accelerated up to 2.3 MeV/u. The beam longitudinal emittance was evaluated by measuring bunch shapes while the bunching field amplitude of the upstream resonator was varied. In this paper, we will present the SiD setup and measurement results.
FRIB, East Lansing, Michigan, USA
NSCL, East Lansing, Michigan, USA
The present RFQ of ReA3 reaccelerator at Michigan State University (MSU) has been commissioned in 2010. This 4-rod RFQ was designed to accelerate the prebunched 80.5 MHz beams with the lowest Q/A = 1/5. However, the lack of proper cooling limited the RFQ performance to the pulsed operation with the lowest Q/A = 1/4. The design voltage for Q/A = 1/5 has never been reached even in a pulsed mode due to the sparking. In 2016 we initiated the upgrade of ReA3 RFQ to support high duty cycle (up to CW) operation with Q/A = 1/5 beams. The upgrade included the new rods with trapezoidal modulation, and new stems with improved cooling. The redesigned 80.5 MHz RFQ will consume only 65% rf power of the present RFQ for Q/A = 1/5 beam. It will provide the transmission up to 78% for 16.1 MHz beams and 89% for 80.5 MHz beams. High reliability and efficiency of the RFQ are very important for the going-on reaccelerator upgrade to ReA6 and for future operation as a part of FRIB. The electrodes have been manufactured and are being installed. The RF and beam tests are scheduled to summer 2019.
FRIB, East Lansing, Michigan, USA
The Facility for Rare Isotope Beam (FRIB) includes a heavy ion superconducting (SC) linac. Recently we completed beam commissioning of the Linac Segment 1 (LS1) and 45° bend section of the Folding Segment 1 (FS1). Four ion species, 40Ar9+, 20Ne6+, 86Kr17+ and 129Xe26+ were successfully accelerated to a beam energy of 20.3 MeV/u. We explored the possibility of non-invasive beam diagnostics for online beam envelope monitoring based on beam quadrupole moments derived from Beam Position Monitors (BPMs)*. In future operations, various ion beam species will be accelerated and minimization of beam tuning time is critical. To address this requirement, it is beneficial to use BPMs to obtain beam Twiss parameters instead of wire scanners. This paper reports the results of BPM-based beam Twiss parameters evolution in the FS1.
* R. E. Shafer, "Laser Diagnostic for High Current H beams", Proc. 1998 Beam Instrumentation Workshop (Stanford). A.I.P. Conf. Proceedings, (451), 191.
FRIB, East Lansing, Michigan, USA
NSCL, East Lansing, Michigan, USA
The FRIB Front End was successfully commissioned in 2017 with commissioning goals achieved and Key Per-formance Parameters (KPP) demonstrated for both 40Ar9+ and 86Kr17+ beams. Two more ion species, 20Ne6+ and 129Xe26+, have been commissioned on the Front End and delivered to the superconducting linac during the beam commissioning of Linac Segment 1 (LS1) in March 2019. In August 2019, Radio Frequency Quadrupole (RFQ) conditioning reached the full design power of 100 kW continuous wave (CW) that is required to accelerate Ura-nium beams. Start-up/shutdown procedures and opera-tional screens were developed for the Front End subsys-tems for trained operators, and auto-start and RF fast re-covery functions have been implemented for the Front End RFQ and bunchers. In this paper, we will present the current commissioning status of the Front End, and per-formance of the main technical systems, such as the ECR ion source and RFQ.
FRIB, East Lansing, Michigan, USA
The beam commissioning of linac segment 1 (LS1) composed of fifteen cryomodules consisting of total 104 superconducting (SC) resonators and 36 SC solenoids was successfully completed. Four ion beam species, Ne, Ar, Kr and Xe were successfully accelerated up to 20.3 MeV/u. The FRIB driver linac in its current configuration became the highest energy continuous wave hadron linac. We will report a detailed study of beam dynamics in the LS1 prior to and after stripping with a carbon foil.
NSCL, East Lansing, Michigan, USA
FRIB, East Lansing, Michigan, USA
The reaccelerator facility ReA3 at the National Superconducting Cyclotron Laboratory is a state-of-the-art accelerator for ions of rare and stable isotopes. The first stage of acceleration is provided by a 4-rod radio-frequency quadrupole (RFQ) at 80.5 MHz, which accelerates ions from 12 keV/u to 530 keV/u. The internal copper acceleration structure of the RFQ was re-designed. The goal was to improve transmission while allowing to operate the RFQ in CW and accelerating ions with A/Q from 2 to 5. In this paper, we summarize the steps involved in the disassembly of the existing structure, preparation work on the retrofitted vacuum vessel, installation of the new components, acceptance testing, and commissioning of the completed RFQ.