Development of Allison scanner to measure transverse emittance at low energy beam transport of rare-isotope accelerator complex for ON-line experiments

The Rare-isotope Accelerator complex for ON-line experiments is a heavy-ion accelerator facility that accelerates a stable or rare isotope beam up to 400 kW with an energy of 200 MeV/u. Various heavy-ion beams are generated from the Electron Cyclotron Resonance Ion Source, with an energy of 10 keV/u and separated according to A/Q at the first dipole magnet (DM). To measure beam transverse emittance at the Low Energy Beam Transport section, two Allison scanners are installed behind the DM for the X and Y directions. It consist of a servo motor for driving, a Faraday cup for current measurement, deflection plates, and electronic device. The measurable range of beam angle in of the Allison scanner is determined by the structure of the deflection plate and designed based on mathematical calculations. Experimental Physics and Industrial Control System (EPICS) is adopted to integrate and control a variety of devices. To control the complex measurement sequence of the Allison scanner, an EPICS sequencer module was used. Normalized emittance is calculated by python code with Pyepics module using phase space distribution data. In this paper, we present the detailed design of the Allison scanner, the configuration of the control system, and the experimental results using an Ar9+ 30 mu A beam.

Automated summary

This paper presents the design, configuration, and experimental results of the Rare-isotope Accelerator complex for ON-line experiments, which is a heavy-ion accelerator facility capable of accelerating stable or rare isotope beams up to 400 kW with an energy of 200 MeV/u. The Allison scanners, installed after the first dipole magnet (DM), are used to measure beam transverse emittance at the Low Energy Beam Transport section. Experimental Physics and Industrial Control System (EPICS) and an EPICS sequencer module are employed for device integration and control of the complex measurement sequence. Normalized emittance is calculated using python code with the Pyepics module and phase space distribution data.