FRIB, East Lansing, USA
The commissioning of the FRIB Front End with 12 keV/u argon beam started in the spring of 2017*. Beam profile monitors were used to evaluate RMS Twiss parameters in various locations along the beam line. Beam dynamics in the LEBT was simulated using full 3D model of beam optics elements in the tracking codes. We found a good consistency between measured and simulated data. A beam image viewer was used to measure the beam density distribution in the real space. A hollow beam structure was observed in the Ar9+ beam with the current of ~20 eμA. Extensive beam dynamics study with 3D tracking code suggests that the hollow density distribution can be generated by space charge effects of the multi-component, multi-charge state ion beam just after the ECR ion source. This paper reports studies of a mechanism that can produce a hollow beam structure.
*E. Pozdeyev, invited talk at this conference
FRIB, East Lansing, USA
NSCL, East Lansing, Michigan, USA
This paper presents recent developments of accelerator physics related topics for the Facility for Rare Isotope Beams (FRIB) being built at Michigan State University. While extensive beam dynamics simulations including all known errors do not show uncontrolled beam losses in the linac, ion beam contaminants extracted from the ECR ion source together with main ion beam can produce significant losses after the charge stripper. These studies resulted in development of beam collimation system at relatively low energy of 16 MeV/u and room temperature bunchers instead of originally planned superconducting ones. Commissioning of the Front End enabled detailed beam physics studies accompanied with the simulations using several beam dynamics codes. Settings of beam optics devices from the ECR to MEBT has been developed and applied to meet important project milestones. Similar work is planned for the beam commissioning of the first 3 cryomodules in the superconducting linac.
FRIB, East Lansing, USA
LBNL, Berkeley, California, USA
We are planning to use two types of the accelerator simulation codes for FRIB (Facility for Rare Isotope Beams). One is the linear envelope tracking code "FLAME" for fast simulations. FLAME can calculate the FRIB-linac beam envelope within an order of ms. This is useful in systematic surveys, wide range optimizations and so forth. This code, written in C++, was designed with Python interface from the beginning. On the other hand, "Advanced-IMPACT" is the particle tracking code dedicated for precise and realistic calculations, which can simulate the particle losses, nonlinear and space-charge effects. This code is refactored from the Fortran code IMPACT-Z developed in LBNL. Both codes provide the compiled modules for Python to support flexible inputs and direct outputs management in memory. In other words, they can be directly connected to the modern scientific tools through the Python interface without delay in the data transport. In addition, these modules can accomplish the interactive simulation processes without losing computational efficiency. We report the knowledges applicable for other accelerator simulation codes among those obtained through these developments and designs.