2016/10/28 核融合・加速器科学分野合同 計測技術ワークショップ

Investigation of irradiation effects onhighly integrated leading edge
electronic components of diagnostics
and control systems for the LHD
deuterium operation
K. Ogawa1,2, T. Nishitani1, M. Isobe1,2, I. Murata3,Y. Hatano4, S. Matsuyama5, H. Nakanishi1,2, K. Mukai1,2,M. Sato1, M. Yokota1, T. Kobuchi1, T. Nishimura1,and M. Osakabe1,2
1NIFS, NINS, Japan, 2SOKENDAI, Japan

3Osaka Univ., Japan, 4University of Toyama, Japan,
5Tohoku Univ., JapanIntroduction• Large Helical Device is controlled by means of many semiconductor
integrated circuits placed around LHD in the torus hall with remotecontrol capability.
• However, the radiation damage due to neutron and/or gamma-ray may
lead to serious impact on those systems in deuterium campaign started
from March 2017 and continues for nine years.
• Irradiation tests on semiconductor integrated circuits were intensively
performed in the 1990s in irradiation facilities for ITER. It is reported thata programmable logic controller (PLC) was broken by 1000 Gy gammaray irradiation.
• At present, the radiation resistance of electronic components mightchange because of higher integration of integrated circuits comparedwith integrated circuits of more than 20 years ago.
• Therefore, the effects due to irradiation on electronic components being
used currently should be investigated for control and measurement ofLHD deuterium plasmas.

MCNP calculation• For precise estimation of theradiation field in the LHD torus hall,
MCNP6 is used with ENDF B-VI.
• The geometry in one toroidal pitch
angle is modelled based on theCAD drawing with somesimplification.
• The neutron source is isotropic andhomogeneous in the torus with theenergy of 2.45 MeV.

MCNP Model of LHD.

The figure is made with SuperMC

Neutron flux and Dose profile• Neutron flux profile in the LHD torus hall at maximum neutron
emission discharge (total neutron emission rate of 1.9×1016 s-1)
• The flux in the torus hall and basement level are around 109 cm-2s-1
and around 106 cm-2s-1, respectively.

• The profile of the dose on silicon during the nine years of the LHD
deuterium operation period.
• Dose for silicon is about 70 Gy. The gamma-ray contributions are
dominant in dose.

DD Neutron irradiation test
DD neutron irradiation test in OKTAVIAN• DD Neutron irradiation tests are
performed in OKTAVIAN at
Osaka University and Fast
Neutron Laboratory at Tohoku
University for 11.5 hours.
• Neutron rate from source isaround 9×108 n/s (measuredwith activation foil).
• The neutron flux at 5 cm awayfrom the target is up to
3×106 cm-2s-1.
• The neutron flux at 10 cm awayfrom the target 7×105 cm-2s-1.

Summary neutron irradiation experiment on electronic equipment of LHD (1)ModelnumberNeutron flux
[cm-2s-1]

Transienteffect

Neutronfluence[cm-2]

Permanenteffect

4×109

Not observed

Component

Manufacturer

PC

HewlettPackard

HP Mini 5103

3×105

Network
disconnection(Once)

Media
converter

D-LinkDMC-700SC

7×105

Not observed

8×109

Not observed

IR camera

Indigo

Omega

7×105

Dots
appeared

8×109

Not observed

MPPC

Hamamats
u photonics

C133661350GA

7×105

Not observed

8×109

Not observed

3×1010Not observed

Webcamera

I-O DATA

TS-WLCAM

3×106

Dots
appeared(< 1 Hz)

APD

Hamamats
uphotonics

C12703-01

2×105

Pulse(1.5 Hz)

2×109

Not observed

PMT

Hamamatsuphotonics

H10723-210

2×105

Pulse
(23 Hz)2×109

Not observed

Summary neutron irradiation experiment on electronic equipment of LHD (2)Component

Manufacturer

CPU

Neutronflux[cm-2s-1]

Transienteffect

SP71-4S

PermanenteffectNot observed

Not observed
3×106

YOKOGAWA

Neutronfluence[cm-2]

Network
disconnection(three times)

PU10-0S

Power
PLC1

Model
number3×1010Not observed

Analoginput

AD04-0V

Not observed

Not observed

AnalogoutputDA04-1N

Various effects

Not observed

CPUCJ2MCPU31

Not observed

Not observed

PowerCJ1WPA205C

Not observed

Not observed

OMRON

PLC23×105

4×109

AnalogoutputCJ1WDA021

Not observed

Not observed

Analoginput

CJ1WAD041-V1

Not observed

Not observed

Neutron induced dots on IR camera
Before irradiation

Dots appeared before irradiation

After irradiation

Neutron induced dots
(disappear after reboot)• We observed four dots per 3 hours at neutron flux of 7×105 cm-2s-1.
• The IR camera will be installed on the upper port of LHD where expected
maximum neutron flux is 1010 cm-2s-1.
• If the number of dots linearly grows as neutron flux, the number ofdead pixels due to neutrons will reach 43,000 dots per shot.

Transient effect on PLC1
Analog output signal of PLC1

• We observed disconnection ofnetwork of PLC1 three times during
neutron irradiation test.
• The behavior of output signal module isdifferent in each case.

• Case A: output signal goes to zero
• Case B: no change (though PLC
connection failed)• Case C: output signal goes to 11 V
(maximum output voltage)• These disconnection of the network
recovers due to the reboot.
• No error is observed on PLC2 whenneutron flux of 3×105 cm-2s-1
Network disconnection

60Co gamma-ray irradiation test

• Gamma-ray irradiation tests
are performed in the Nagoya
University Cobalt-60
irradiation facility for 3.7 hours.
• The dose rate on silicon(2015/7/14) is 86 Gy/h at 30 cm
from the source and 30 Gy/h at
50 cm from the source.

Summary gamma-ray irradiation experiment on electronic equipment of LHD (1)ModelnumberMaximum
dose (Gy)

TransienteffectPermanenteffect

HewlettPackard

HP Mini
5101

320

Not observed

Broken(224 Gy)

D-LinkDMC-700SC320

Not observed

Not observed

TOKYO
KEISO

R-760-E

240

Not observed

Not observed

Isolation
amplifierNF
corporation

P62-A

112

Not observed

Not observed

Webcamera

I-O DATA

TS-WLCAM

112

Dots appeared Not observed

Component Manufacturer

PCMediaconverter
OpticalflowmeterSummary gamma-ray irradiation experiment on electronic equipment of LHD (1)Component

PLC1

PLC2

Manufacturer

ModelnumberCPU

PU10-0S

PowerSP71-4S

Analoginput
AnalogoutputYOKOGAWA

Maximum
dose (Gy)112
AD04-0V
DA04-1N

TransienteffectPermanenteffectDotsappearedBroken (86 Gy)

Notobserved
Notobserved
Not
observed

Broken (86 Gy)
Not observed
Offset increase
Broken (86 Gy)

CPU

CS1GCPU42H

Not
observed

Not observed

Power

C200HWPA204S

Not
observed

Broken (112 Gy)

Notobserved

Not observed

Not
observed

Broken (95 Gy)

OMRON
AnalogoutputCS1WDA08V

Analoginput

CS1WAD08-V1

112

Offset increase due to gamma-ray on PLC1Setups• MODEL:FA-M3, YOKOGAWA

Irradiation roomBNCPLCDC power
supplyAnalog
input

EthernetPC• DC voltage (2 V) is inputted to analog
input module on a PLC.
• The input signal is monitored by a PC.
• Offset due to gamma-ray is graduallyincreased.
• Analog input module is broken at 86 Gy.

analog input module is broken

13Permanent effect on PLC2
• MODEL: CS1G,OMRON

Setups• Time-varying voltage is applied
from analog output module toDevicenet input on the PLC.

Irradiation roomWirePLC

Analog output
Devicenet input

PCEthernet• The input/output voltage ismonitored through a PC.
• Devicenet input is broken at 95 Gy.
• Ethernet module and power moduleof PLC are broken at 112 Gy.
Ethernet and power module are broken
Devicenet input module is broken

14Summary• Effects of neutron and gamma-ray irradiation on electronic equipment currently usedin the LHD torus hall are studied in OKTAVIAN, Fast Neutron Laboratory, and Nagoya
University Cobalt-60 irradiation facility.
• The irradiation on PCs, media converters, the IR camera, an MPPC, web cameras,APDs, PMTs, PLCs, optical flow meters, and isolation amplifiers are performed.
• In neutron irradiation test, the disconnection of the network is observed on the PC at
neutron flux of 3×105 cm-2s-1, and on PLCs at neutron flux of 3×106 cm-2s-1. This
neutron flux is comparable with the flux at the basement level of the LHD torus hall.
The experiment also shows that there is no effect on the PLC on the neutron flux
below 3×105 cm-2s-1.
• Neutron-induced dead pixels are observed on the IR camera. These dots disappear
due to reboot. Neutron-induced signal is observed on APDs and PMTs. No effect isobserved on the media converter and the MPPC at neutron flux of 3×105 cm-2s-1 andneutron fluence of 8×109 cm-2.
• This neutron and gamma-ray irradiation test shows that highly integrated electronic
components such as PLCs and PCs will have a trouble in the torus hall without
neutron shield, and equipment used in this experiment can survive nine years of
deuterium operation in the torus hall if we consider the gamma-ray dose only.
• Hence, we designed the neutron shield for the IR camera, and we moved PCs andPLCs as far as possible to the basement level of the torus hall and put several neutron
shields made by the borated polyethylene for the safe operation of LHD deuterium
experiments.