II-8. Accelerator

RIKEN Accel. Prog. Rep. 55 (2022)

RIKEN Accel. Prog. Rep. 55 (2022)

Distributed control by EPICS for the SRILAC beam energy position
monitoring system using LabVIEW†
T. Watanabe,∗1 A. Kamoshida,∗1,∗2 A. Uchiyama,∗1 N. Fukunishi,∗1 R. Koyama,∗3 and K. Kaneko∗3
For stable operation of the newly constructed Superconducting RIKEN Heavy-ion Linac (SRILAC), nondestructive and highly sensitive measurement using thebeam energy and position monitor (BEPM) system isessential.1,2) A great advantage of this system is that it
can handle a time-chopped beam by synchronizing themeasurement system with the beam chopping signal.
Although the chopped beam intensity is of several electric nA, we can measure the beam position and energy
to accuracies of ±0.1 mm and precision in the order of
10−4 , respectively.
These measurements and controls are programmedwith LabVIEW. Further, by sharing these measuredvalues, such as beam positions and beam energies, witha large-scale EPICS control system, it is easy to obtainthe correlation of each relevant machine parametersin time series. A block diagram of the BEPMs anddata-acquisition system is shown in Fig. 1. All themodules, including digitizers, multiplexers and a embedded controller, are integrated into a PXI expresschassis. The signal process procedures are controlledusing the LabVIEW 2020 graphical programming language, and the module drivers are supported by theNational Instruments Corporation. The obtained data
are shared using CA Lab, which is a user-friendly,
lightweight, and high performance interface between

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Fig. 2. Measured results showing the relationship between
the beam position at BEPM 1 and the vacuum between
cryomodules of CM1 and CM2.

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the LabVIEW program language and the EPICS-based
control system. It allows easy reading and writing of
EPICS process variables (PVs). The PVs used by theBEPM system include analog inputs, wave-forms, andanalog and binary outputs. The measurement results
are displayed on a local remote desktop. Furthermore,
once these data are saved to PVs, the Control System
Studio (CSS), which is an Eclipse-based tool to operate a large-scale control system, can display the results
anywhere in the control room.
Figure 2 shows one example of the measured results,
which presents the relationship between the beam position at BEPM 1 and the vacuum between the cryomodules of CM1 and CM2 when the 51 V13+ beam intensity
is increased to 2.5 particle μA. Based on this measurement, we established that the vacuum rapidly became
worse when the beam position shifted from −1 mm to−2 mm. Therefore, we changed the EPICS interlock
system to start the beam attenuator automatically toprevent vacuum deterioration.

We are currently working on measurement of thequadrupole moment to obtain the beam size, beam
intensity from the bunched signal, and TOF using a
lock-in amp technique.
References

Fig. 1. Block diagram of the BEPMs and DAQ.
†∗1
∗2∗31) T. Watanabe et al., Proc. the 18th Annual Meetingof Particle Accelerator Society of Japan, (Online, Aug.
2021), pp. 683–686.
2) T. Watanabe et al., Proc. 2020 Int. Beam Instrumentation Conf. (IBIC2020), (Santos Brazil, Online, Sept.
2020), pp. 295–302.

Condensed from the article in Proceedings of the 18th Annual Meeting of Particle Accelerator Society of Japan, (2021)
p. 683
RIKEN Nishina Center
National Instruments Japan Corporation
SHI Accelerator Service Ltd.

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