temperature dependence on electrostatic discharge in a … · 2010-10-21 · temperature dependence...

2010/ 9/ 222010/ 9/ 2211th Spacecraft Charging Technology Conference

New Mexico, USATemperature Dependence on Electrostatic

Discharge in a Simulated Space Plasma

,

Discharge in a Simulated Space Plasma Environment

T, Okumura. J, Harada. Y, Hagiwara. K, Nitta. M, TakahashiJapan Aerospace Exploration Agency

T, Toshimitsu. K, ToyodaKyushu Institute of Technologyy gy

BackgroundNo2

Time

tial

Vcgee

e e

Pote

nt

e e ee

Vsat

Depends on temperature??Depends on temperature??Discharge number estimationgProper experiment condition for ESD test

Collaboration researchNo3

Temperature dependence on primary discharge

JAXA KITThreshold LEO

Temperature dependence on primary discharge

JAXA KITThreshold GEOThreshold voltage

LEO

Discharge LEO

Threshold voltage

GEO

Discharge LEOfrequencyfrequency

No4

Threshold of differential voltageThreshold of differential voltage

Experiment technique and result

Experiment system (JAXA)No5

Electron beam gunSurface potential meter

IR camera

PC

PCPC

Discharge positionTemperature monitor

Vb

Cext V

Analog signalOSC

Discharge circuitHeat panel

Shroud

OscilloscopeDischarge circuitHeat panel

Solar array couponNo6

35mm75

mm MJ cell

CG =100m7

Experiment system (JAXA)No7

Shroud

Solar array couponXY stageTREK

H t l

Solar array coupon

Heat panel

Experiment conditionNo8

• Pressure: 5x10-5PaPressure: 5x10 Pa• Current density: 4mA/m2

A l i l 9k• Acceleration voltage: 9kV• Bias voltage: 6kV

Discharge circuitNo9

C5C3C2C1

Rb280pF

C4

Rb280pF

VbV Vp

CB

Test sequenceNo10

Surface potential distribution

Beam irradiation

NoDischarge?

Elapsed timeYes

No

YesNo

Elapsed timex sec

Surface potential distribution

Discharge position and current waveform No11

20’C -110’C

Discharge position and surface potentialNo12

20’C -110’C

Surface potential profileNo13

Threshold voltage

Charging speed

Low temperature Room temperatureLow temperature Room temperature

Threshold volatageNo14

Room Low temperature temperature

Threshold 1.3kV 1.4kVvoltage

Standard 0.5 0.1deviation

Threshold voltage does not depend on the temperatureon the temperature

No15

Discharge frequencyDischarge frequency

Experiment technique and result

Experiment system (KIT)No16

ECR plasma sourcePC

QMASS

IR camera

PC

PC

Discharge positionShroud

Vb

Cext V

Analog signal OSC

Discharge circuit

Sheet heater

OscilloscopeDischarge circuit

Experiment system (KIT)No17

ShroudQMAS ShroudQMAS

Solar array coupon

Solar array couponNo18

35mm

75m

m

MJ cellCG =100mCG 100m

Test sequenceNo19

Expose to air for 3hours

Experiment: Room temperature for 60min

p

Increase the temperature by seat heater Increase bias voltage

Experiment: High temperature for 60min

Decease the temperature by LN2

Experiment: Low temperature for 60min

Experiment conditionNo20

CouponVbias[

V]Experimenttime[min] Ne[1/m3] Te[eV] Pressure

[Pa]

Coupontemperature[ ]High room lowh

-200 60 6×1012 0.7 2.9×10-264~66

30~31

-34~

-29

-300 60 7×1012 0.7 2.7×10-264~65

30~30

-42~

-34

-400 60 7×1012 0.7 3.6×10-263~65

20~39

-46~

-33

Temperature dependence on discharge numberNo21

Bias Room(30℃) High(60℃) Low(-30℃)-200 0 1 6-300 3 9 28-400 15 11 60

Discharge frequencyLow temperature Room temperaturep p

Same result as JAXA

SummaryNo22

• Threshold differential voltage does not depend on temperature g p pin GEO environment

• Arc frequency increases with decreasing temperature in JAXA d KITand KIT

• Discharge number estimation• Discharge number estimation– We need to concern the temperature to estimate the charging speed of

insulation material

i di i f S• Proper experiment condition for ESD test– In terms of GEO environment test to investigate the threshold voltage,

we do not need to care about the temperature

Future workNo23

• ESD test under GEO environment in KITESD test under GEO environment in KIT• Absorbed material effect on discharge

frequencyfrequency