The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

Operation Control System for the Storage Ring of SPring-S
Masaru TAKAO, Schin DATE, Keiko KUMAGAI, Mitsuhiro MASAKI, Takamasa MASUDA,Takeshi NAKAMURA, Haruo OHKUMA Jun-ichi OHNISHI, Takashi OHSHIMA, Taihei SHIMADA,Kouichi SOUTOME, Shiro TAKANO, Hitoshi TANAKA, Koji TSUMAKI and Noritaka KUMAGAI
SPring-8, Kamigori, Ako-gun, Hyogo 678-12, Japan

Abstract

HP-UX
The operation procedure and the cQntrol system for the storage ring of SPring-8 are reported with focusing on the injection and the storage of the electron beam.

1 Introduction
The construction of SPring-8, a third generation light source
facility, was completed in March 1997 and the commissioning of the storage ring started immediately. The facility consists of a 1 GeV linac, an 8 GeV booster synchrotron andan 8 GeV low emittance storage ring. The storage ring has
a capability of constructing 61 beamlines, 23 of which arefor insertion devices. 1\vo beamlines were constructed at theearly stage of the commissioning, other five beamlines wereset up three months later.
In this report we describe the way of the operation and thecontrol system of the storage ring of SPring-8. In particular,
the injection and the storage of the electron beam are illustrated.

2The Framework of the Storage Ring Control System

The storage ring control system consists of engineering workstations (EWS), VMEbus systems and optical fiber network(FDDI) system [1]. The remote procedure call (ONC/RPC)
is used for the communication between machine control applications over the network. The operation history and theequipment parameters are stored on a database by relational
database management system (RDBMS), Sybase.
The structure of the storage ring control system is shown inFig. 1 [1, 2]. An operator command is issued to the message
server (MS) by using a control panel. The MS forwards thereceived message to the access server (AS) after checking thesyntax. The AS resolves the destination of the message andsend it to the equipment manager (EM) running on the remote
CPU board. There are individual AS's corresponding to theequipment groups, e.g. RF, magnet, vacuum and so on. The
EM manages the VME devices connected to equipment controllers. The status data of the equipments are accumulatedvia another communication path, poller/collector system, andsaved on the on-line database by Sybase.
The constituents of the control panels are listed in Table
1, which constitute the hierarchy structure as well as the machine components.S see Fig. 2.
At the first level there is a top control panel operating
SPring-8 as a whole. The control panels for the constituent
accelerators of SPring-8, the linac, the synchrotron and theRPC call to read only EM

Figure 1: The structure of storage ring control system. The
ellipses denote independent processes, respectively.

Figure 2: The structure of the control panels. The roundsquares denote the individual control panels.

-344-

The lith Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

Table 2: Major parameters of the storage ring in daily operation.

Table 1: Major contents of the control panels.
SPring-S top panel
SR control panel
main magnet control panel
injection magnet tuning panel
steering magnet control panel
RF control panel
BPM control panel
vacuum control panel
injection timing (filling pattern) set panel
injection ready confirm panel
COD correction panelring lattice parameter tuning panels
stored current and beam life time display panelpressure distribution display panel

stored electron energy
limit current of stored electron beam
RF frequency
harmonic number
repetition rate of injection pulse
injection pulse length

storage ring, belong to the second level. At present, the control panel of the storage ring can be opened by the top panel,since the linac and the synchrotron are operated by the different control system from that of the storage ring. However,
the main parameters, such as current and energy of the linac
and the synchrotron, can be acquired and indicated on theSPring-S top panel. It is planned to integrate them for thesake of operation brevity.
The main panels for the equipment groups, i.e. magnet,
RF, monitor and vacuum, are located in the third level ofthe hierarchy structure. A main panel of equipment groups
includes the sub-panels as various needs arise. In addition
to the panels for the equipment groups, we have the panels which lighten the operation burden. They are the COD
correction panel, the injection timing set panel, the injection
ready confirm panel, and so on.
Most of the data of the machine parameters of the storage
ring are centrally managed by means of the database. The status data of the equipments on the online database are updated
every 5 seconds with some exceptions. Since the repetition
rate of the injection is 1 Hz, it is necessary to store the data of
the stored current every second. In setting a parameter of anequipment, the control panel updates the data on the parameter database, so that another control panel easily know the set
value by the access to the database.
To smoothly tune the storage ring parameters, the online analysis of the data is indispensable. The COD correction panel [3] and the the lattice parameter tuning panel dosuch analysis and set the resultant machine parameters to theequipments. To help understanding the data intuitively, thetools displaying the data graphically on the widgets made by
X-Mate were developed.
We list the major functions of the control panels used indaily operation except for those of the equipment groups.
• SPring-S control panel
1. saves operation parameters of SPring-S accelerator

modules as a whole,

SGeV
20mA
50S.5SMHz
2436
1Hz40ns2. opens SR control panel,
3. displays the status of the constituent accelerators,
4. displays the operation mode,
5. limits the stored current,
6. forbids to inject the electron beam into the storage
ring if the condition is not satisfied, and7. changes the alarm condition according to the operation mode.
• SR control panel
1. saves operation parameters of whole storage ringequipments,
2. manages the control panels and the status display
panels for the equipment groups, and3. aborts the stored current.
• injection timing (filling pattern) set panel
1. produces the injection pattern data of the pulse
number and the addresses, and2. sets the injection pattern data.
• injection ready confirm panel
1. confirms the ready status of the equipments of thestorage ring.
The tasks of the control panels for the equipment groups areto access to the modules and to display the status.
3 The Beam Operation of the Storage Ring

In this section, we illustrate the beam injection into the storage ring as an example of the operation. The ways of startingup the power supplies of the equipments, the magnets and theRF system, are found in [4, 5].
The operation parameters related to the beam injection tothe storage ring are listed in Table 2. An injection pulse contains 20 bunches in series, all of which but one are eliminatedby RF knock out in synchrotron in the case of single bunch
operation [6].
The beam injection control system is shown in Fig. 3. The
electron gun at the linac is fired only by the beam on-switch
on the beam control panel hardwired to the gun. Although thelinac gun trigger is turned off by pushing the beam off-switch-345-

The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

database. When the stored current amounts to the set value,
the top panel stops the beam injection by issuing the gun-off
request command. In the case that the stored current data are
not updated due to the failure of the data taking system, thebeam injection is stopped by the software interlock supplemented to the top panel. As a last resort oflimiting the storedcurrent, we set up the beam abort module hardwired to theDCCT. If the stored current measured by the DCCT exceeds
the threshold, the module sends the beam abort signal to theRF system and the gun-off signal to the safety PLC.
Besides, there is the case that the control panel issues thegun-off request. If the injection ready conditions, as shown)_n the following list, become to be not satisfied, the gun-off
request is issued.

beam control panel

1. The power supplies of the magnets have the fixed values.
2. The RF system has the fixed accelerating voltages withthe fixed phases.
3. The check of the DCCT is completed.
4. The gate valves at photon-beam extraction ducts areopened.
Figure 3: The electron beam injection control system. Theround squares indicate the software applications and the rigid
ones the hardware modules.
on the beam control panel, the operation control applications
can issue the linac gun-off request to the PLC system managing the radiation safety. Once the gun-off request is issued
and if not reset, the beam on-switch is immediately turned off
by the PLC.
The RF bucket, where the top bunch of the injection pulse
is located and which is called the address, is determined by
the non-stop counter of 508.58 MHz [6]. In the operation
with high current, the beam is injected into the storage ringwith varying the address, since we should retain the peak current of the stored electron in the low level because of the beaminstability. The injection address is managed by the process,or EM agent (EMA), running on the VME directing the timing system. In a similar manner the injection pulse number
is controlled by another EMA on the VME communicatingwith the radiation safety system.
The beam injection is managed by the following two regulations, (a) the injection pulse number limit and (b) the current limit. For the limit (a), the safety EMA watches theon/off status of the beam switch with 10 ms period. If thebeam switch is turned on, the EMA starts to count down theinjection time and, after the injection pulse number reaches
to the limited value, the EMA gives the command of turning
off the linac gun to the safety PLC. As a backup to the process, the top panel also count down the beam injection time.
· Provided the process fails to stop the beam injection, the top
panel issues the gun-off command a few second after the expiration of the injection time.
For limit (b), the stored current measured by the DCCT
is monitored by the top control panel through the on-line

5. The gaps of the insertion devices are fully opened.
6. The main beam shutters of the beamlines are closed.
The gun-off state demanded by the top panel is reset by thepanel itself after the conditions are made prepared and thestored current falls below the threshold.

4Conclusions

The first stage of the commissioning of the storage ring is justfinished, which is successfully accomplished by the help of
the control panels. The flexibility and the expansibility of thecontrol panels made the commissioning to go on smoothly.

References[I] R. Tanaka, et al., in Proc. of Int. Conf. on Accelerator andLarge Experimental Physics, Chicago, 1995.
[2] A. Taketani, et al., ibid..
[3] H. Tanaka, et al., in these proceedings.
[4] T. Ohshima, et al., in these proceedings.
[5] H. Takebe, et al., in these proceedings.
[6] H. Suzuki, et al., in these proceedings.

-346-