The neutrino beam line control system
Y. Suzuki, Y. Yamanoi, M. Ieiri, H. Ishii, Y. Kato, M. Minakawa
H. Noumi, K. H. Tanaka, M. Takasaki
Institute of Particle and Nuclear Studies, KEK
Tsukuba, Ibaraki, Japan

Abstract
The construction of the beam line for the long base-line
neutrino oscillation experiment is in its final stages now.
This beam line consists of a 400m proton beam section
and a 200m pion decay section. In the proton beamsection, there are 104 magnet power supplies, and two
250kA pulse power supplies operated synchronously with
12GeV proton synchrotron. These components areinstalled in three houses far from each other. The demands
for the control system, are low cost, high reliability, andgood assistance of the maintenance of power supplies.
On this situation, as components of the control system,
PC and POD (Programmable operation display), and LAN
and GPIB are adopted. The system controller is the PC
with Windows NT, and controls magnet power supplies
and 250kA pulse power supplies through LAN and GPIB.
For operator, the PC offers control panel on the POD
through LAN, and also offers status display of magnet
power supplies as Web service. The low-level magnet
power supply controller has GPIB interface, and isconnected to LAN.

1 Introduction
The speeds of improvement in computers are very fast.
The devices expected to use in the control system werechanged. Two years ago, when the design work for theneutrino beam line control system started, a WS (HP-UX)
and a PC (WindowsNT4.0) was introduced, and tested
them. The test result was that the PC was 12 times fasterthan the WS. On the performance of Web service the PC
was faster 6times. Finally, the PC with Pentium
450MHz CPU as the system controller was chosen. Xterminal for user interface device was changed to POD(programmable operation display). As the programming
language of the control system HP-VEE was chosen.

2 System configuration
Figure 1 shows the configuration of the control system.
As the system controller PC WindowsNT4.0 has Pentium
450MHz CPU and 384MB memory. HP-VEE 5.0 isinstalled as programming language. The POD is originallythe user interface device dedicated to the PLC(programmable logic controller). The POD is
programmed as the user interface of the neutrino beamline control. The POD is connected to LAN through aterminal (RS-232c) server TOA-7413. Magnet power
supplies in the North experimental hall is connected tostPSCx8 (eight magnet power supply controller). In 1 andnd
2 power station, magnet power supplies are also
connected to PSCx8. The PSCx8 is connected to PC
through GPIB or LAN. Seventeen auxiliary low power
supplies are also connected through LAN/HP-IB gateway
and HP-IB extender 37204A. There are two 250kA pulse
power supplies for Horn-magnets. Each of those have ahorn power supply controller (HPSC). The HPSCcontrols not only the pulsed power, but also the timing ofthe synchronisation to the 12GeV proton synchrotron. [1]

3 PSC
The PSCx8 is the interface to control eight magnet
power supplies. It has a ROM-based microcomputer, andeasy to maintain. The PSCx8 communication protocol isGPIB. The GPIB is a popular interface. When PSC istested with PC, the PSCx8 is connected to PC directlywith GPIB cable without LAN. Finally the PSCx8 isconnected to LAN through LAN/HP-IB Gateway or HPIB extender. The complicated procedure of magnet power
supplies operation is installed in the PSCx8. Therefore thecommunication between the PC (system controller) andPSCx8 becomes simple, dose not disturb the LAN.

4 HPSCThe horn magnet power supply controller is themodified device of the power supply controller (PSC)
which was developed 10 years ago, and have been runningin K6 and Pi2 beam line. The improvement has done on
timing control and timing measurement. The function is
performed in one-chip IC Z80-CTC (counter timer circuit).
The capacitor charge of the HMPS is done by feed theregulator circuit the ramped reference voltage controlled
by microcomputer. The trigger timing of 250kA pulse iscontrolled with the CTC, and the 250kA pulse is
synchronised to the fast extraction beam from the 12GeV
proton synchrotron. The coincidence of the proton beamand 250kA pulse is measured by the CTC. This HPSC has
also GPIB interface, and connected to LAN through
LAN/HP-IB Gateway E2050.

5 User interface POD
The POD was selected for the user(operator) interface.
The reason is that there is any account or any shard
resource for users on the system computer or PC. The
second reason is the POD has coloured effective display
function, and decreases the load of he system controller
PC.

6. System programming
The system programming of the neutrino beam line is
performed with HP VEE 5.0. By the original function theVEE is able to communicate with the PSCx8, HPSC, andTOA-7413. The PSC and HPSC perform the complicatedoperation of the magnet power supply. Therefor the loadof the PC is reduced, and the communication between thePC and the PSC or HPSC is becomes simple.

7. Web service
By the original VEE function the neutrino beam line
control system offers Web service. The beam line statusor the magnet power supplies conditions are monitored
through Web browser.
The actual Web transfer speed is below,
230k Bytes / 3sec,
66 k Bytes / 1or 2 sec(WS speed is 170 k Bytes / 14 sec, 47 k bytes / 6 sec)

8. Conclusion
When look back over the development work of thecontrol system, some chief points are as follows.
1. Powerful PC.
2. PSCx8, HPSC lower level controllers perform thecomplicated operation of the magnet power supplies.
3. The communication between PC and low levelcontrollers is simple message.
4. The user interface is offered on POD (programmableoperation display).

REFERENCES[1] Y. Suzuki, et al. “Control and Timing of the 250kA
Pulsed Magnetic Horn”, ICALEPCS’97, China 1997