Control and monitoring system of gas strippers

R. Koyama∗1,∗2 and H. Imao∗1

We report on the control and monitoring system ofa gas stripper, a new RIBF charge stripper using agas target. A gas stripper has been developed as analternative to a traditional carbon-foil stripper for in-creasing the intensity in very heavy ion beams such asuranium or xenon beams at the RIBF. A recirculatinghelium gas stripper1) and an air stripper2) are installedat the A02 site after the RRC and at the M04 site afterthe fRC (GS-A02 and GS-M04), respectively.

The schematic block diagram of their control andmonitoring system is shown in Fig. 1.

124Xe20+

238U35+

124Xe40+

238U64+

He gas

MBP array

99.6%recircula�on

Forelinetrap

He Target

Heatexchanger

124Xe40+ 124Xe52+

Air Target

Air compressor

PT2PT1

PT3

BF1 BF2 BF3OT1 OT2 OT3 OT4

: Rotary pump

: Turbomolecular pump

: Mechanical booster pump

GS-M04

Orifice temp. : OT1-8& Pump temp. : PT1-3

(K-type Thermocouple)

Buffle current: BF1-5(beam loss monitor)

Windows PC@Local(LabVIEW program)

MyDAQ2server

(Data record)

USB/Serial

Pressure gauges:(M-360CP,M-350PG/Cannon Anelva)

Gauge controller(M-603GC/Cannon Anelva)

DeviceNet

PCILabVIEW EPICS

Client I/O Server

Mass flow controller(FCST1500FD/Fcon)

DeviceNet interface(NI PCI-8532/Na�onal instruments)

Channelaccess

EPICS control system

Beam interlock system

USB

TC

P/I

P

CompactDAQ chassis(NI cDAQ-9171,9172/Na�onal instruments)

Solid-state relay(NI 9485/Na�onal instruments)

Serial

TCP/IP

TCP/IP(Network

shared variables)

Serial-to-Ethernet converter(NI ENET-232/Na�onal instruments) Thermocouple module

(NI 9213/Na�onal instruments)

Serial

Control unit(RVC 300/Pfeiffer Vacuum)

Gauge controller(XGS-600/Agilent)

Gas regula�ng valve(EVR 116 -> RME 005 A/Pfeiffer Vacuum)

Pressure gauges:(CDG-500/Agilent, MG-2/Cannon Anelva)

BF4 BF5OT5 OT6 OT7 OT8

GS-A02

Windows PC@Console(LabVIEW program)

Fig. 1. Schematic block diagram of control and monitoring

system for gas strippers.

We developed a user-friendly GUI program using theLabVIEW for the system, which includes the following:

• Remote control of the pressure and/or flow rateof the target gas

• Monitoring of the pressure of each differentiallypumped section

• Monitoring of buffle current BF1–BF5 (beam lossmonitor) via the EPICS control system3,4)

• Monitoring of the temperature of orifices OT1–∗1 RIKEN Nishina Center∗2 SHI Accelerator Service Ltd.

OT8 and mechanical booster pumps PT1–PT3• Signal output to the beam interlock system in re-

sponse to the monitoring value via the NI Com-pactDAQ

• Data recording to the MyDAQ2 system3)

The developed system allows us to remotely opti-mize the target pressure of gas strippers with the as-sistance of the online beam monitoring system5). Fig-ure 2 shows the correlation among the target pressureof GS-A02, beam timing, and beam intensity nonde-structively observed by a phase probe (PP).

He

liu

m g

as

targ

et

pre

ssu

re [

Pa

]

PP

-G0

1 b

ea

m in

ten

sity v

aria

�o

n [%

]

PP

-D1

5 b

ea

m �

min

g d

ri� [n

s]

He gas targetpressure

Beam intensity

Beam �ming

Time [min]

6350

6400

6450

6500

6550

6600

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0 5 10 15 20 25 30-14

-12

-10

-8

-6

-4

-2

0

2

Fig. 2. Correlation among target pressure of GS-A02, beam

timing, and beam intensity observed by the phase

probe.

In this case, the beam timing at PP-D15 (31 mdownstream of the GS-A02) gradually varied owing tothe energy loss reduction in the GS-A02 as its tar-get pressure decreased6), resulting in a ∼10% decreasein beam intensity at PP-G01 (5 m downstream ofthe SRC). The beam intensity was recovered by twicefine controlling the target pressure by observing thebeam monitoring system, as indicated by the arrowsin Fig. 2. The pressure should be regulated with ±1%accuracy by the control unit, however, it got out-of-control at the end of the machine time, so we specu-late that its accuracy was reduced owing to irradiationdamage to the regulating valve EVR 116 near the GS-A02 in the RRC vault. EVR 116 has been replacedwith radiation-proof RME 005 A.

References1) H. Imao et al.: Proc. of IPAC2013, Shanghai, China,

May 2013, THPWO038, p.3851 (2013).2) H. Imao et al.: Proc. of IPAC2014, Dresden, Germany,

Jun. 2014, THPME067, p.3388 (2014).3) M. Komiyama et al.: Proc. of ICALEPCS2011, Greno-

ble, France, Oct. 2011, MOPKN005, p.90 (2011).4) R. Koyama et al.: RIKEN APR 46, 135 (2013).5) R. Koyama et al.: Nucl. Instr. Meth. A 729, (2013) 788.6) H. Imao et al.: in this proceedings.

Beam Energy and Longitudinal Beam Profile Measurement Systemat the RIBF†

T. Watanabe,∗1 M. Fujimaki,∗1 N. Fukunishi,∗1 H. Imao,∗1 O. Kamigaito,∗1 M. Kase,∗1 M. Komiyama,∗1

N. Sakamoto,∗1 K. Suda,∗1 M. Wakasugi,∗1 and K. Yamada∗1

Monitors with plastic scintillators as sensors (scin-tillation monitors) were fabricated to measure the en-ergy and longitudinal profiles of heavy-ion beams atthe RIKEN RI beam factory (RIBF). Six pairs of twoscintillation monitors installed in the transport lineswere used to measure the particle time-of-flight (TOF)between the paired monitors to determine the acceler-ation energy of the heavy-ion beams. The energy ofthe beam can be calculated from the measured TOF.In addition, five scintillation monitors were installedto measure the longitudinal profiles of the heavy-ionbeams. Longitudinal beam profiles were obtained byusing a time-to-digital converter (TDC), which digi-tizes the detected signals from the scintillator and theRF clock signal. Recently, to help users operate thesystem more easily, a new embedded processor witha higher-performance CPU has been introduced, anda new user interface has been constructed using theLabVIEW program.

For data acquisition and control of the scintillationmonitors, we developed a ccompactPCI system thatuses a Windows-based PC1). Signals from the de-tectors are amplified and converted to logic pulses bya constant-fraction discriminator. The TDC digitizesthis pulse along with the RF clock and stores the eventsinto the memory of the TDC. The TDC (TC890) hastwo memory banks based on a so-called ping-pongmemory architecture that enables data readout whilethe module continues to acquire events. When a bankis ready to be read, an interrupt is generated, andthe readout starts in the direct memory access mode.

Upstream C20 Downstream C22

Fig. 1. Longitudinal profiles the 19F9+ beam measured at

C20 (upstream) and C22 (downstream) in the AVF cy-

clotron beam transport line as displayed on the graph-

ical user interface.

† Condensed from the proceedings in 5th International Parti-cle Accelerator Conference (IPAC’14)

∗1 RIKEN Nishina Center

0

2000

4000

6000

8000

10000

12000

0 5 10 15 20

C20 : Fitted by Gaussian function

C22 : Fitted by Gaussian function

TD

C Y

ield

(co

un

ts)

Time (ns)

C22 C20

(1- ):

7.23 deg.

(1- ):

6.67 deg.

Center TC22 :

6.95 ns

Center TC20 :

13.00 ns

Fig. 2. Gaussian functions fit to the rightmost beam pro-

files at C20 and C22 in Fig. 1.

The programs for the data acquisition, control, and forshowing results are written in LabVIEW (Windows7).The PCs are connected to a laptop in the main con-trol room located 100 m from the Riken ring cyclotron(RRC) hall via Ethernet and remote desktop connec-tion. The EPICS system controls insertion of the mon-itor into the beam line or its retraction from the beamline and it monitors these statuses.

We measured the energy of a 19F9+ beam acceler-ated by the AVF cyclotron by using the TOF method.The 19F7+ beam was used to produce element 105,262Db from a target of 248Cm2). Because the sequen-tial double pulse resolution was 15 ns, the 19F9+ beamwas attenuated to be under 1 M s−1 using beam atten-uators. The longitudinal profile of the 19F9+ beam wasmeasured at C20 (upstream) and C22 (downstream) inthe AVF cyclotron beam transport line were displayedon the graphical user interface as shown in Fig. 1. Therightmost longitudinal profiles obtained at C20 andC22 in Fig. 1 are expanded and plotted in Fig. 2. Byfitting the profiles in Fig. 2 with Gaussian functions, wedetermined the center times TC20 and TC22 of the pro-files and the longitudinal phase widths (1-σ), as shownin Fig. 2. The beam kinetic energy (TTOF ) obtainedby measuring the TOF was 6.81 MeV/u. In addition,the beam kinetic energy (TBρ) can be determined bythe magnetic field of the bending magnet that bendsthe 19F9+ beam because the field was already knownas a function of the exciting current. In this measure-ment, the hysteresis effect was not taken into account.The kinematic energy TBρ was determined to be 6.80MeV/u. These energies are in good agreement, with adifference between TTOF and TBρ of 0.1%.

References1) T. Watanabe et al.: RIKEN Accel. Rep. 43, 135 (2010).2) M. Murakami et al.: RIKEN Accel. Rep. 47, 265 (2014).

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Ⅱ-8. Accelerator RIKEN Accel. Prog. Rep. 48 (2015)RIKEN Accel. Prog. Rep. 48 (2015) Ⅱ-8. Accelerator

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