Prototype Control System of the 60-MeV Proton Linac for the J-PARC Project

Norihiko Kamikubota , Junsei Chiba , Hidetoshi Nakagawa , Noboru Yamamoto ,
Kazuro Furukawa , Jun-ichi Odagiri , Susumu Yoshida , Makoto Takagi and Tadahiko KatohHigh Energy Accelerator Research Organization (KEK) Oho, Tsukuba, Ibaraki, 305-0801, Japan Kanto Information Service Co. Ltd. (KIS) 8-21, Bunkyo, Tsuchiura, Ibaraki, 300-0045, Japan
Abstract
J-PARC, a high-intensity proton accelerator facility,
started construction in 2001, and expects an anticipatedfirst beam in the summer of 2007. The initial 60-MeV ofthe proton linac has been under construction at KEK. Early
studies with proton beams have already started. A prototype control system based on the EPICS toolkit has beendeveloped and evaluated in beam studies.

1 INTRODUCTION
J-PARC (Japan Proton Accelerator Research Complex) is a high-intensity proton accelerator facility, which
consists of a 400-MeV linear accelerator, a 3-GeV RCS(Rapid Cycle Synchrotron), and a 50-GeV MR (MainRing) [1, 2]. This is a joint project between JAERI 1 (inTokai) and KEK (in Tsukuba). Although the construction
site is Tokai, the initial 60-MeV part of the linac has been
under construction at the Tsukuba site. Early studies withproton beams already started in 2002 [3]. The 60-MeV
linac will be moved to Tokai at the end of fiscal year 2004.
EPICS (Experimental Physics and Industrial ControlSystem) is a software toolkit used to develop a distributed
real-time control system for large accelerators. It is now
widely used in many accelerator institutes [4]. We decidedto use EPICS to control the J-PARC accelerators [5, 7].
A prototype control system based on EPICS has been developed at KEK for the 60-MeV linac. The advantages are
as follows: (a) to evaluate newly developed interfaces andsoftware with real accelerator beams, (b) to provide staff
members chances to use an EPICS-based control system inthe early phase of the project, and (c) to support the commissioning activities at the 60-MeV linac.

2EPICS AT THE 60-MEV LINAC

2.1 Network-based interfaces
The J-PARC control staff members in KEK have beeninterested in network-based interfaces [6]. In the 60-MeVlinac control, we have used the following network-based
interfaces: (a) a Programmable Logic Controller (PLC)with an Ethernet module, (b) an embedded controller fora power-supply (hereafter EMB [8]), and (c) a measurement station WE7000 (see 2.3). The development status ofEPICS drivers is summarized in Table 1.

 E-mail: norihiko.kamikubota@kek.jp

1 Japan Atomic Energy Research Institute.

Table 1: EPICS drivers for network-based interfaces.
Inter- EPICS
Memo
face
device.supportand update
PLC(Feb01)
PLC (Yokogawa FA-M3)
andTest version
used until Apr.03EMB (Feb03)
both PLC (Yokogawa
NetDev [9]FA-M3) and EMB(Apr03) update PLC (Mitsubishi Melsec-Q)(May03) update EPICS3.14+LinuxWE(Mar02)
WE7111 (100MS Oscillo.)
7000
1st version
WE7121 (10MHz Func.G.)[10]
WE7271 (100kS Digitizer)(May03) update add station-bus commands(Jul03) bug-fix
WF –  Calc conversion

2.2 PLC and EMB
In the KEK 60-MeV linac, PLC (Yokogawa FA-M3)
is widely used as a front-end interface. The first EPICS
driver for the PLC was developed in 2001 [6]. This test
version had been used for monitoring the ion-source until
April, 2003, and was then replaced by a new driver, NetDev(see below).
The EMB controller was developed as a dedicatednetwork-based controller for the DTL/SDTL-Q powersupplies. A remote host can read and/or write EMB’s registers over the network by exchanging simple messages [8].
The EPICS driver, NetDev, was developed for various network-based interfaces with a simple communication protocol: Yokogawa’s PLC (FA-M3), EMB, and Mitsubishi’s PLC (Melsec-Q). Descriptions are given in [9].

2.3 WE7000
In the J-PARC accelerators, the remote observation ofwaveforms is indispensable. A commercial product, Yokogawa WE7000 [13], is a module-type measurement station. We expected that the oscilloscope/digitizer modules
of WE7000 can be used as low-cost network-based waveform monitors.
In fiscal year 2001, we developed three EPICS drivers of
the WE7000 modules: a 100 MS/s oscilloscope (WE7111),
a 100 kS/s digitizer (WE7271), and a 10MHz function generator (WE7121), followed by small updates and bug-fixes
during the shutdown period of 2003.
Evaluations of the 100 MS/s oscilloscope module

(WE7111) were carried out. The data-acquisition time of aone 5kB-size waveform is about 33 ms, and 23 ms per 5 kB
when eight waveforms are transferred at once [10].

3CONTROL FOR THE 60-MEV LINAC

3.1 Computers and Networks

power-supplies and beam-monitors) was impossible. We
decided to migrate such small control systems into a single
EPICS-based control system.
We are now in the summer shutdown to extend the proton linac to have DTL (drift-tube linac) sections. The next
commissioning will start in October, 2003. During theshutdown, we have been developing as many applications
as possible to control the linac devices.

3.3 Status for each Linac Device
kek.jpFigure 1: Computers and Networks.
The computer system is shown in Fig.1. It consists of:(a) 4 VME-bus computers (shown as IOCs in Fig.1), (b)a HP-UX server (jhfacc1) as the main development server,(c) 2 BSD-based servers (jhfacpc01,02) for supplemental
functions of the main server, (d) 5 Linux-based personal
computers for operator’s consoles, and (e) 7 personal computers (Linux, BSD, Windows) for development.
In 2003, we introduced the following: (f) 2 NAS (network attached storage, each 180GB) systems to share program sources and archive data, and (g) a Linux server(jkksv01, now in test) for development and beam studies.
These computers are connected with a private network (jhfacc) dedicated to control of the 60-MeV linac.
In addition, we have a web server (jhfacsv03) and a
database server (jhfacsv02), which are connected with thelaboratory network (j-parc.jp). The server computers have
two networks (both private and laboratory networks). The
relationships are also shown in Fig.1.

3.2 Control and Beam Commissioning
The development of a prototype control system started
in 2001. The main purpose was to study and evaluate an
EPICS-based control system. By the end of 2002, we succeeded to control the pre-injector part of the linac.
Due to historical reasons, the control of each linac device
was developed independently by a device group. For example, the power-supplies of the MEBT (Medium-energy
beam-transport) were controlled by a stand-alone PC (see3.3). Such a situation caused problems: (a) remote operation from the central control room was unavailable,and (b) inter-communication between different devices (i.e.

Pre-injector The pre-injector part (the ion-source and thepre-chopper) uses PLC’s. They have been successfully
controlled since 2002.
MEBT power-supply There are 13 power-supplies (hereafter PS’s), each of which has a GPIB interface, controlled
by a PC using LabView. In February, 2003, we changed theGPIB host from a PC to a LAN/GPIB box (Agilent E5810),
the driver of which was developed in the EPICS community [12]. We then developed an application to control theMEBT PS’s by using dm2k 2 . Later, we added 6 PS’s with
the EMB interface, but this modification was easy, sincethe EMB has an EPICS driver (NetDev). Fig. 2 shows thecontrol application of the MEBT PS’s.

Figure 2: Control panel for the MEBT power-supplies
DTL-Q power-supply In the summer shutdown, we installed the 77 DTL-Q magnets. Each DTL-Q has a PS withan EMB interface. We developed an application, and havealready used successfully it in test runs since August, 2003.
Other devices The timing system is controlled by a one
PLC; 32bit-length delay values are supported. An application was developed and delay control functions have already been confirmed. The control for the RF system isunder development. It uses 2 PLC’s.3 The status of thebeam-monitor development is described in 3.4.
2 A standard EPICS tool to develop graphic user interfaces.
3 One PLC for the low-level RF, another for klystron power-supplies.

Summary In Table 2, we summarize the development status of the linac devices in September, 2003. Most of theinterfaces in Table 2 will be used for the Tokai site accelerators, except for the timing system [11].
Table 2: Development status of the 60-MeV linac devices.
DeviceInterface
Develop- EPICS databasex Number ment
and GUI/dm2k
IonPLCx1
1999db configured
source2002
ready in 2002
PrePLCx1
Aug.
db configured
chopper
2002
ready in 2002
MEBT
GPIBx13 Feb.
db configured
PS’s
EMBx6
2003
ready in Feb.03
DTL-Q EMBx77
Jun.-Aug. draft db
PS’s
2003
test run in Aug.03
Timing
PLCx1
Apr-Aug
db configured
2003
test run in Aug.03
RFPLCx2
underunderdevelop.
development

3.4 Status for Beam Monitors
There are four different beam-monitors: current
monitor (CT), phase monitor (FCT), beam-position monitor (BPM), and wire scanner (WS) [2]. In the summer
shutdown, applications for CT, FCT and BPM have beendeveloped. We use the WE7111 modules (see 2.3) as frontend interfaces for all of these beam monitors.

tem from a PC-based system 4 to the EPICS-based controlsystem. Fig. 3 is a screen copy of the dm2k application,
which contains waveforms of three CT signals.5 Migration makes it possible to observe beam-currents at any (andmultiple) console terminal.
After various updates, the data-acquisition rates withdummy signals have been measured. The observed ratesof 3 waveforms (each 5 kB) are from 6 Hz (average mode)
to 10 Hz (normal mode) [10].
The development of applications for the FCT and theBPM was carried out during the summer shutdown. We
will start evaluations of these applications with real beams
soon during the next commissioning.

4 CONCLUSION
We have developed a prototype control system basedon EPICS for the J-PARC 60-MeV proton linac. EPICS
device supports for network devices (NetDev) and for theWE7000 waveform monitors have been developed.
Application development has been completed for the following devices: the ion-source, the pre-chopper, MEBT
power-supplies, DTL-Q power-supplies, and the timingsystem. Control for the RF system is still in the development phase. The controls of these devices will soon beinspected during the next commissioning.

5REFERENCES[1] Y.Yamazaki, ”The JAERI-KEK Joint Project (the J-PARCProject) for the High Intensity Proton Accelerator”, Proc.
PAC 2003, May 12-16.2003, Portland, in press[2] Y.Yamazaki, ”Accelerator Technical Design Report for JPARC”, KEK-Report 2002-13; JAERI-Tech2003-044[3] M.Ikegami, et.al., ”Beam Commissioning of the J-PARC
Linac Medium Energy Beam Transport at KEK”, Proc. PAC
2003, May 12-16.2003, Portland, in press[4] http://www.aps.anl/gov/epics/[5] J.Chiba et.al., Proc.of the ICALEPCS 2001, San Jose, CA,Nov.2001, p.77-79[6] K.Furukawa et.al., ”Implementation of the EPICS Device Support for Network Based Controllers”, Proc.of theICALEPCS2001, San Jose, CA, Nov.2001, p.197-199[7] T.Katoh et.al., ”Present Status of the J-PARC Control System”, this conference[8] K.Furukawa et.al., ”A Network-based Intelligent Controller
for J-Parc”, this conference[9] J.Odagiri et.al., ”EPICS Devices/Driver Support Modules
for Network-based Intelligent Controllers”, this conference[10] M.Takagi et.al., ”Network-based Waveform Monitor for theJ-PARC Accelerator Complex”, this conference[11] F.Tamura et.al., ”J-PARC Timing System”, this conference

Figure 3: Observation of CT waveforms.

[12] http://www-csr.bessy.de/control/SoftDist/gpib/lanGpib.shtml[13] http://www.yokogawa.com/html/tmc/tm/4sg tm/tmwe7000 01.htm
4 Visual Basic environment with commercial libraries of WE modules.

In February, 2003, we migrated the CT monitoring sys-

5 The beam-currents in Fig. 3 were zero, since it is under development.