0.000
0.500
1.000
1.500
2.000
2.500
0.000
0.500
1.000
1.500
2.000
2.500
0.0075 0.0095 0.0115 0.0135 0.0155 0.0175 0.0195 0.0215 0.0235 0.0255 0.0275
Resistamce (mOhms)
Compression force (lbf)
Compression (in)
GS2100 Radiation exposure FDR data
Post Rad Avg mOhm Control Avg mOhm Control Avg load lbf Post rad Avg load lbf
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
10 20 30 40 50 60 70 80 90 100 110 120 130 140
Stress (MPa)
Percent Strain
GS2100 Radiation Test Data
Samp 1 Samp 2 Samp 3 Samp 4
Samp 5 Samp 6
Samp 7 Samp 8
Samp 9 Samp 10 Samp 11
Samp 12
Control Group
Test Group
0
Control Group:
Test Group:
GORE
®
EMI Gaskets
GS2100 SERIES, GS5200 SERIES
Radiation Testing for
Space Applications
GORE
®
EMI Gaskets, GS2100 Series is commonly used in
applications where the environment includes exposure to
ionizing radiation. Spaceight applications would be an
example where this would be a consideration. The environment
in space can be damaging to the materials or electrical
properties of component parts. Testing was performed on
GS2100 Series and GS5200 Series to better understand the
effect of ionizing radiation on the material and electrical
properties of these EMI gasket materials.
The test was performed by exposing material samples of
GS2100 Series and GS5200 Series to gamma radiation from a
Cobalt 60 source, (3 MeV). These samples were evaluated for
tensile properties (See Table 1 and Figure 1 & 3) and changes
in the “Force Displacement Resistance (FDR)” measuring DC
resistance with compression (See Figure 2 & 4). Radiation
exposure was performed under vacuum to remove oxygen and
better simulate a spaceight environment. The sample sets
were divided into two groups: a control group with no exposure
to radiation and a test group exposed to a total dose of 1.04
MRad, with a dose rate of 118 Rad/sec.
The samples in the test group for both GS2100 Series and
GS5200 Series demonstrated a decrease in both tensile
strength and elongation due to exposure to gamma radiation.
Tensile testing was based on ASTM D638-08 Type V, gage
length=1, rate=10 mm/min.
The exposed samples in each test group did not exhibit any
particulation when handled. The reduction in tensile strength
and elongation did not cause any difculty with sample
preparation for testing.
Figure 1: GS2100 Series Radiation Tensile
Testing
The GS2100 Series demonstrated a 55% drop in maximum load
and a 61% drop in elongation. The changes in both of these
parameters can be attributed to the degrading effect of the
ionizing radiation on the base PTFE material. These changes are
consistent with what would be expected of PTFE materials after
this sort of environmental exposure. GS2100 Series is intended
to be used under conditions of compression, which suggests
that changes in tensile performance would not disqualify this
material for “Fitness for Use
1
”.
The GS2100 Series was tested for FDR and the average of ve
samples was plotted in the graph below (See Figure 2). The
x-axis was based on the Instron gage length set with the starting
point slightly above the material thickness.
No signicant changes in FDR performance were observed
between the control group and test group.
Figure 2: GS2100 Series, Force Displacement
Resistance Performance with Radiation Exposure
Table 1: Radiation Tensile Testing
Materials
under Test
Max load (lbf) Elongation @ break (%)
Control Group
Test Group
Control Group
Test Group
GS2100 Series
0.609 0.275 132 51
GS5200 Series
0.473 0.317 65 28
1
At Gore, one of our core values is our commitment to delivering products that meet our customers'
expectations and are t for their intended end use.
Samp 1 Samp 2 Samp 3 Samp 4
Samp 5 Samp 6
Samp 7 Samp 8
Samp 9 Samp 10 Samp 11
Samp 12
Control Group:
Test Group:
Percent Strain
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
0 10 20 30 40 50 60 70 80 90
Stress (MPa)
GS5200 Radiation test data
Test Group
Control Group
W. L. Gore & Associates, Inc.
gore.com/emi
GORE, and designs are trademarks of W. L. Gore & Associates. ©2017 W. L. Gore & Associates, Inc. MAT-0323-REF-US-JUN17
Radiation Testing for Space Applications
NOTICE — USE RESTRICTIONS APPLY
Not for use in food, drug, cosmetic or medical device
manufacturing, processing, or packaging operations.
Figure 3: GS5200 Series Radiation Tensile
Testing
Figure 4: GS5200 Series Force Displacement
Resistance Performance with Radiation Exposure
The GS5200 Series demonstrated a 33% drop in maximum load
and a 57% drop in elongation (See Figure 3). The changes in
both of these parameters can be attributed to the degrading
effect of the ionizing radiation on the base PTFE material. These
changes are similar to the changes found in the GS2100 Series.
Subtle differences in the material conguration for each of
these EMI gaskets are likely to contribute to the differences in
changes in tensile properties. The key observation is both PTFE
based materials are degraded by the exposure to the ionizing
radiation, but the impact of the changes at 1 MRad dose, does
not signicantly change the electrical properties of the material
and the remaining tensile performance is capable of supporting
“Fitness for Use”.
No signicant changes in FDR performance were observed
between the control group and test group.
Conclusions:
The exposure to radiation under vacuum conditions caused a
signicant decrease in the tensile and elongation properties
for both GS2100 Series and GS5200 Series. The materials did
maintain basic integrity and did not exhibit any particulation,
which suggests in an installed, compressed condition, both
GS2100 Series and GS5200 Series would continue to provide
typical shielding benets for use. FDR data did not reveal any
signicant changes in either material’s electrical properties due
to the radiation exposure.
The main design consideration highlighted by the results
presented in this report is the importance of understanding the
application environment with respect to radiation exposure.
“Life time” radiation dose estimates for component parts can
be used with this summary to identify any areas of concern for
“Fitness for Use”.
GORE
®
EMI Gaskets
GS2100 SERIES, GS5200 SERIES
Post Rad Avg mOhm Control Avg mOhm Control Avg load lbf Post rad Avg load lbf
Resistamce (mOhms)
Compression force (lbf)
Compressed position (in)
GS5200 Radiation exposure FDR data
0.0095 0.0115 0.0135 0.0155 0.0175 0.0195 0.0215
0.0000
0.5000
1.0000
1.5000
2.0000
2.5000
0.0000
0.5000
1.0000
1.5000
2.0000
2.5000