\>From: Martin Seifert \<mfseifert@lucent.com\>

\>To: \"\'Craig Mueller\'\" \<Craig.T.Mueller@aero.org\>,

\> Martin Seifert

\> \<mfseifert@lucent.com\>

\>Cc: \"frank.t.buzzard1\"

\<\"/dd.NOTES=frank.t.buzzard1@notes.aero.org!jsc.nasa.gov@notes.aero.org!In/\"

\@notes.aero.org\>,

\> \"John.S.Canham.1\" \<John.S.Canham.1@gsfc.nasa.gov\>,

\> \"john.a.white2\"

\> \<john.a.white2@boeing.com\>,

\> me \<me@leidecker.gsfc.nasa.gov\>,

\> jkolasin

\> \<jkolasin@pop700.gsfc.nasa.gov\>,

\> \"melanie.ott\"

\> \<melanie.ott@gsfc.nasa.gov\>,

\> jplante \<jplante@swales.com\>,

\> \"ray.prestridge\" \<ray.prestridge@lmco.com\>,

\> \"david.w.beverly1\"

\> \<david.w.beverly1@jsc.nasa.gov\>,

\> Anna \<Anna@seawire.traveller.com\>, DChalk
\<DChalk@BICCGeneral.com\>,

\> DZevotek \<DZevotek@BICCGeneral.com\>,

\> DRothermel \<DRothermel@BICCGeneral.com\>,

\> David Young \<youngd@lucent.com\>,

\> \"harold.f.battaglia\" \<harold.f.battaglia@boeing.com\>,

\> moorec

\> \<moorec@pgocm1.ksc.nasa.gov\>,

\> BANKSE \<BANKSE@pgocm1.ksc.nasa.gov\>,

\> \"Daniel.Tambert-1\" \<Daniel.Tambert-1@kmail.ksc.nasa.gov\>,

\> \"david.j.gill2\"

\> \<david.j.gill2@boeing.com\>

\>Subject: RE: Reply to ESD comments by Martin

\>Date: Mon, 20 Mar 2000 08:59:12 -0500

\>X-Mailer: Internet Mail Service (5.5.2650.21)

\>

\>Thanks; I\'ll wait for the Goddard observations. I have one concern
from

\>your response and that is that the ion air wipe is/was always on. A
year

\>ago when we were working on the 170 vs 172 micron fiber mix up our
trip

\>report, copied to BICC, indicated the respooling machine was not
equiped

\>with an ion air wipe machine at all. This would tend to refute the

\>assertion that such a device was always on.

\>martin

\>

\>\-\-\-\--Original Message\-\-\-\--

\>From: Craig Mueller \[mailto:Craig.T.Mueller@aero.org\]

\>Sent: Thursday, March 16, 2000 5:18 PM

\>To: mfseifert

\>Cc: frank.t.buzzard1; John.S.Canham.1; john.a.white2; me; jkolasin;

\>melanie.ott; jplante; ray.prestridge; david.w.beverly1; Anna; DChalk;

\>DZevotek; DRothermel; youngd; harold.f.battaglia; moorec; BANKSE;

\>Daniel.Tambert-1; david.j.gill2

\>Subject: RE: Reply to ESD comments by Martin

\>

\>

\>Response to your questions regarding ESD damage during the re-spooling

\>process:

\>

\>\>Did we reconcile the measured breakdown voltage of the polyimid
fiber

\> at

\>Goddard with the calculated value at Aerospace?

\>

\>As I indicated in my last email, we now have a measured value of 3900
V for

\>15 microns or 6500 V/mil of the breakdown voltage (dielectric
strength) of

\>the polyimide. Comparing this to the latest data sheet in the
literature, I

\>

\>find that it might be slightly lower than that measured by Dupont
(7700

\>V/mil). John Canham (Goddard) indicated that they also have measured
this

\>parameter and I will let them present their data. However, I believe
that

\>John quoted a number about a factor of two different lower than both
our

\>data

\>and the value given in the latest data sheet from Dupont.

\>

\>\>It appears to me that we need to resolve this gap. It is big enough
to

\>reverse the conclusion craig makes from his observations.

\>

\>My conclusion was that the fields measured near the pulleys while the

\>re-spooling machine was operating were a factor of 1000 lower than the

\>fields

\>required to break down the polyimide. Recall that the meters we used

\>measured a difference of 4500 V/inch or 4500 kV/mil at the highest
speed

\>tested, 50 m/min. Factors of two differences in the dielectric
strength

\>would not change this conclusion.

\>

\>\>I think it is important to acknowledge that all fiber spooling
processes

\>tend to \"create static electricity\". A simple test on an insulating
fiber

\>is to turn off the ion bath machine and turn on the spooler. You can
easily

\>feel the field intensity with your hand unless it is a very humid day,
but

\>even then it\'s not much of a stretch. Somebody can measure or model
this if

\>they need to.

\>

\>My understanding is that the de-ionizer is always on when the fiber
was

\>re-spooler as it was during the test. Recall that we measured the
strength

\>of the field near the take-up spool and found it to be low. If that
were

\>not

\>the case, it would be possible for the charge on the fiber and any
isolated

\>spool or pulley to build up. However, unless there is a potential
differnce

\>

\>between the take-up spool and another payout spool, this would not
cause

\>problems. The charge on the take-up spool would merely buildup until
it

\>discharged through air to a conduction path on the re-spooling machine

\>chassis. Remember the dielectric strength of the air is 20-70 kV/in,
well

\>below the dielectric strength for the polyimide (6500 kV/in).

\>

\>\>I would be interested in establishment by experimentation of the
\"minimum

\>but sufficient\" voltage potential required to electrically discharge
through

\>two layers of the polyimid coating.

\>

\>Our experiments consist of a high voltage source connected to 40 Mohm
in

\>series with the fiber. We found that it takes at least 3900 V
(6500/mil) to

\>

\>break down a single layer of polyimide (15 microns thick). When
breakdown

\>occurs, we observed a significant amount of damage to the polyimide

\>consisting of dark, burned areas.

\>

\>Craig

\>

\>

\>

\>

\>mfseifert@lucent.com on 03/16/2000 09:29:00 AM

\>To: Craig Mueller/West/Aerospace/US@Aerospace,

\>John.S.Canham.1@gsfc.nasa.gov@Internet

\>cc: mfseifert@lucent.com@Internet, john.a.white2@boeing.com@Internet,

\>me@leidecker.gsfc.nasa.gov@Internet,
jkolasin@pop700.gsfc.nasa.gov@Internet,

\>

\>melanie.ott@gsfc.nasa.gov@Internet, jplante@swales.com@Internet,

\>ray.prestridge@lmco.com@Internet,
david.w.beverly1@jsc.nasa.gov@Internet,

\>Anna@seawire.traveller.com@Internet, DChalk@BICCGeneral.com@Internet,

\>DZevotek@BICCGeneral.com@Internet,
DRothermel@BICCGeneral.com@Internet,

\>youngd@lucent.com@Internet, harold.f.battaglia@boeing.com@Internet,

\>moorec@pgocm1.ksc.nasa.gov@Internet,
BANKSE@pgocm1.ksc.nasa.gov@Internet,

\>Daniel.Tambert-1@kmail.ksc.nasa.gov@Internet,

\>david.j.gill2@boeing.com@Internet,
frank.t.buzzard1@jsc.nasa.gov@Internet,

\>klw@lucent.com@Internet, djd@lucent.com@Internet,

\>hleideck@pop500.gsfc.nasa.gov@Internet

\>Subject: RE: Reply to ESD

\>

\>Did we reconcile the measured breakdown voltage of the polyimid fiber

\> at

\>Goddard with the calculated value at Aerospace? It appears to me that
we

\>need to resolve this gap. It is big enough to reverse the conclusion
craig

\>makes from his observations.

\>I think it is important to acknowledge that all fiber spooling
processes

\>tend to \"create static electricity\". A simple test on an insulating
fiber

\>is to turn off the ion bath machine and turn on the spooler. You can
easily

\>feel the field intensity with your hand unless it is a very humid day,
but

\>even then it\'s not much of a stretch. Somebody can measure or model
this if

\>they need to.

\>I would be interested in establishment by experimentation of the
\"minimum

\>but sufficient\" voltage potential required to electrically discharge
through

\>two layers of the polyimid coating.

\>thanx

\>mfs

\>

\>

\>\-\-\-\--Original Message\-\-\-\--

\>From: Craig Mueller \[mailto:Craig.T.Mueller@aero.org\]

\>Sent: Wednesday, March 15, 2000 8:41 AM

\>To: John.S.Canham.1@gsfc.nasa.gov

\>Cc: mfseifert@lucent.com; john.a.white2@boeing.com;

\>me@leidecker.gsfc.nasa.gov; jkolasin@pop700.gsfc.nasa.gov;

\>melanie.ott@gsfc.nasa.gov; jplante@swales.com;
ray.prestridge@lmco.com;

\>david.w.beverly1@jsc.nasa.gov; Anna@seawire.traveller.com;

\>DChalk@BICCGeneral.com; DZevotek@BICCGeneral.com;

\>DRothermel@BICCGeneral.com; dyoung@spectran-specialty.com;

\>harold.f.battaglia@boeing.com; moorec@pgocm1.ksc.nasa.gov;

\>BANKSE@pgocm1.ksc.nasa.gov; Daniel.Tambert-1@kmail.ksc.nasa.gov;

\>david.j.gill2@boeing.com; frank.t.buzzard1@jsc.nasa.gov;
klw@lucent.com;

\>djd@lucent.com; hleideck@pop500.gsfc.nasa.gov

\>Subject: Reply to ESD

\>

\>

\>Response to John Canham\'s email

\>

\>\>I have some significant concerns regarding your e-mail stating that
there

\>was no possibility of ESD. This was I believe the consensus at the
meeting

\>that there was disagreement with regard to this matter. There are
issues to

\>be resolved.

\>

\>I did not say there is no possibility that ESD could have occurred,
just

\>that

\>\"based

\>on the measured data we have obtained thusfar, I cannot conclude that
ESD

\>damage to the polyimide coating has occurred during the re-spooling

\>process.\" Note that I did not indicate the consensus of the group at
the

\>meeting, but was attempting to summarize my presentation at the
meeting. I

\>agree there are issues to be resolved\-- Let\'s start by addressing
them.

\>

\>\>What was the relative humidity at the respooler at the time of the
test?

\>We have been given a range of 30-70% for the RH when fiber is run.

\>

\>\>What was the surface resistivity of the cable at the time of the

\>measurement? What is the potential range of the surface resistivity of
the

\>cable?

\>

\>The carbon-coated polyimide fiber was run through the re-spooler so I
will

\>have to assume you are referring to the fiber, not the cable. The

\>resistivity of the polyimide will be quite high and as such will
localize

\>the

\>charge near the two pulleys. If the surface resistivity was reasonable
low,

\>

\>charge will begin to flow along the surface of the polyimide to the
second

\>pulley as the signs of the two fields are opposite. This would serve
to

\>reduce the net charge on the fiber at each pulley and reduce the
change the

\>electric field internal to the polyimide. However, the electric field

\>inside

\>the polyimide can never to more than the field measured outside it.

\>

\>\>What is the uncertainty in the achievable potential, and thus the

\>probability of reaching a discharge potential under different
conditions

\>based upon the fact that surface resistivity changes exponentially
with

\>humidity?

\>

\>Here I presume you are referring to surface resistivity of the
polyimide.

\>Again, if the surface resistivity decreases the charge will flow along
the

\>surface of the fiber, decreasing the amount of localized charge near
the

\>pulleys. If the surface resistivity increases, the charge will remain
on

\>each pulley. Based on the measured field strengths, the charge on the

\>pulleys did not appear to increase beyond a certain point. We did not
see

\>any evidence of discharge from the pulley to the air or the re-spooler

\>chassis. As for the fiber, it is only there for a short period of time

\>before it moves on to the take-up spool. Hence, the amount of charge
on the

\>

\>fiber should remain constant and distributed along its entire length.
This

\>

\>is not a catastrophic problem unless the field increases beyond the

\>dielectric strength of the polyimide. (And the measurements do not
show

\>field strengths this high.) It will, however, cause the fiber to
collect

\>dust.

\>

\>\>From discussions concerning this previously, I believe that it was

\>mentioned that you were not allowed to turn off the lights and operate
the

\>respooler in the dark. What is the probability that you would see a
minor

\>ESD in a lighted production facility? What is the probability that you

\>would see a spark discharge from the fiber core to the roller through
the

\>opaque cable jacket in the dark? in a lighted production facility?

\>

\>I recall that the lights may have been turned off at one point and no
signs

\>of arcing were observed. We also wanted to listen for any audible
sounds

\>from any discharges but could not turn off the noise in the factory.

\>Again,

\>while I can agree it would be hard to see small electrical discharges
taking

\>

\>place, the measured field strengths are still a factor of 1000 too
small to

\>cause breakdown in the polyimide. This would suggest that the air
should

\>break down first and we should be seeing discharges from the fiber to
the

\>chassis of the re-spooler.

\>

\>\>What is the effect of up to 3% water, an unknown percentage of

\>n-methylpyrollidone and an unidentified cure state upon the
conductivity,

\>dielectric strength, and dielectric breakdown strength of the
polyimide

\>coating on the fiber under all of the possible cure conditions and

\>processing conditions at BICC General?

\>

\>\>Furthermore, the presence of absorbed water at up to 3%,

\>n-methylpyrollidone, and HF at unknown concentrations present in the

\>partially cured polyimide, the electrical properties of the film will
not

\>be the same as the pure, properly cured polyimide under laboratory

\>conditions. It is quite reasonable to actually expect a limited

\>conductivity of the film based upon the ionization of the HF under
these

\>conditions.

\>

\>According to Dupont\'s literature on polyimide, the maximum amount of
water

\>it

\>can absorb is 2.8% and the dielectric strength will decrease as the RH

\>increases. At 0% RH they quote 8600 V/mil and at 100%, 6800 V/mil. (We

\>measured 6500 V/mil.) The dielectric constant will also increase with

\>increasing water content but only increases from 3.0 to 3.8 for RH of
0% and

\>

\>100%, respectively. The answer is that the water content has little
effect

\>on the strength of the electric fields or the dielectric strength
(breakdown

\>

\>voltage) of the polyimide.

\>

\>\>Based upon the fact that most electrostatic field meters are
designed and

\>calibrated based upon an assumed infinite plane potential source, can
you

\>provide a representative field strength map in three dimensions for
this

\>system?

\>

\>Looking at the relatively large diameter of the pulleys compared to
the

\>sensing area of the meter, I would suggest that the pulleys appear
like a

\>infinitely large planes of charge to the meter. Obviously, the meters
could

\>

\>be improved upon and I will check to see what other types of meters
are

\>available.

\>

\>Based upon the fact that there is continuous movement in the system,
the

\>system is electrodynamic, with an undefined charge generation rate. If
no

\>discharge occurred, the cable would not be at a given potential, but,
would

\>rather generate charge until either coronal discharge occurred or the

\>machine was stopped.

\>

\>\>As the carbonaceous coating on the fiber is known to have a
resistivity of

\>approximately 600,000 ohms/meter, the existence of a potential field

\>difference on the order of 12,000 V across approximately 0.8 M will
result

\>in a significant depression in the potential through transport of
electrons.

\>

\>\>To support the 12,000 volt potential difference, across the 480,000
ohms

\>resistance requires 25 mA of current. Although I do not have a
quantitative

\>relationship for the current dissipation rate of the SSQ cable, 25 mA
seems

\>a bit too large to be dissipated by surface dissipation and random
charge

\>dissipation events.

\>

\>Like Spectran, we measured the resistivity of the carbon coating on
the

\>fiber

\>to 15 kohm/cm. In the case of static fields (negligible current flow),
the

\>worst case is that the field inside the polyimide is equal to the
field

\>outside. To be completely accurate the electric field is reduced by
the

\>value of the dielectric constant. Nevertheless, the dielectric
strength of

\>the polyimide assumes the voltage is measured across the thickness of
the

\>polyimide in air. Until the polyimide breaks down, no current will
flow and

\>

\>it acts like a good capacitor. This agrees with our experimental

\>measurements of the voltage across the polyimide right up until it
breaks

\>down. After breakdown occurs, current begins to flow and reduce the

\>potential across the remaining polyimide.

\>

\>Would it be reasonable to assume that electric field should be a
function

\>of the rate of cable movement? Would it be reasonable to assume that
in

\>steady state operation that one could expect that two electrostatic
field

\>meters should read within one order of magnitude, or at least the same
the

\>same polarity of charge. Looking at the data from that test, it is
readily

\>apparent that either one or more the meters used in the testing was
out of

\>calibration, the meters were being used improperly or that the

\>electrostatic charge was not static, and that ESD was occurring.

\>

\>Yes, the electric field could be function of the rate at which the
fiber

\>moves through the re-spooling machine. And the data slightly higher
fields

\>when the speed was increased from 20 to 50 m/min. This would imply
that the

\>

\>pulleys are likely discharging at some rate and the resultant field is
the

\>steady state solution for a given charging and discharging rates. If
the

\>pulleys were charging up, we would expect electric discharge to the

\>re-spooler chassis prior to any breakdown of the polyimide.

\>

\>The meters were furnished by NASA and I am not familiar with your

\>calibration

\>requirements. It is possible that one or both the meters were out of

\>calibration, but my understanding from Henning Leidecker\'s remarks at
the

\>meeting was that at least one of those meters was checked against a
charged

\>plate and found to be accurate. There is some question as to whether
the

\>meter would measure a the field from a line of charge, such as the
fiber.

\>We

\>did hold it next to the fiber while the re-spooler was in operation
and

\>found

\>little indication any electric fields away from the pulleys.

\>

\>\>It is not reasonable to assume that the simplifying assumptions made
in

\>your calculation are valid. The inconsistency between meter readings
show

\>that. In the absence of adequate materials property variability data,

\>consistent electric field data with variability, reasonable electric
field

\>modeling, reasonable modeling of the charge flux, reasonable
measurements

\>of the potential between the carbon coating and the rollers and
evidence of

\>a lack of electrostatic discharge in any potential operational case,
rather

\>than a lack of evidence in one case, I would suggest withdrawing the

\>argument for there being no possibility of electrostatic discharge.
Lack of

\>evidence is not evidence of a lack.

\>

\>My assumptions were intended to be worst case. As for the meters, I
will

\>have to rely on your evaluation of their accuracy. Remember if the
field

\>was

\>much higher, we should have seen the air breaking down near the fiber.

\>

\>As for the conclusions, we have not given up trying to recreate the
damage

\>using ESD. But based on the measurements made at BiccGeneral and the
lack

\>of

\>any noticeable presence of defects in the sample of re-spooled fiber
we

\>received, I cannot conclude that ESD is the mechanism for perforating
the

\>carbon coating on the fiber.

\>

\>Craig

\>

\>

\>

\>

\>John.S.Canham.1@gsfc.nasa.gov on 03/14/2000 01:09:00 PM

\>To: Craig Mueller/West/Aerospace/US@Aerospace,

\>john.a.white2@boeing.com@Internet,
me@leidecker.gsfc.nasa.gov@Internet,

\>jkolasin@pop700.gsfc.nasa.gov@Internet,
melanie.ott@gsfc.nasa.gov@Internet,

\>jplante@swales.com@Internet, ray.prestridge@lmco.com@Internet,

\>david.w.beverly1@jsc.nasa.gov@Internet,
Anna@seawire.traveller.com@Internet,

\>

\>DChalk@BICCGeneral.com@Internet, DZevotek@BICCGeneral.com@Internet,

\>DRothermel@BICCGeneral.com@Internet, jli@spectran.com@Internet,

\>dyoung@spectran-specialty.com@Internet,
mseifert@spectran.com@Internet,

\>harold.f.battaglia@boeing.com@Internet,
moorec@pgocm1.ksc.nasa.gov@Internet,

\>

\>BANKSE@pgocm1.ksc.nasa.gov@Internet,

\>Daniel.Tambert-1@kmail.ksc.nasa.gov@Internet,

\>john.a.white2@boeing.com@Internet, david.j.gill2@boeing.com@Internet,

\>frank.t.buzzard1@jsc.nasa.gov@Internet, klw@lucent.com@Internet,

\>djd@lucent.com@Internet, John.S.Canham.1@gsfc.nasa.gov@Internet,

\>hleideck@pop500.gsfc.nasa.gov@Internet

\>cc:

\>Subject: RE: ESD e-mail from today

\>

\>Craig,

\>

\>I have some significant concerns regarding your e-mail stating that
there

\>was no possibility of ESD. This was I believe the consensus at the
meeting

\>that there was disagreement with regard to this matter. There are
issues to

\>be resolved.

\>

\>What was the relative humidity at the respooler at the time of the
test?

\>

\>What was the surface resistivity of the cable at the time of the

\>measurement? What is the potential range of the surface resistivity of
the

\>cable?

\>

\>What is the uncertainty in the achievable potential, and thus the

\>probability of reaching a discharge potential under different
conditions

\>based upon the fact that surface resistivity changes exponentially
with

\>humidity?

\>

\>\>From discussions concerning this previously, I believe that it was

\>mentioned that you were not allowed to turn off the lights and operate
the

\>respooler in the dark. What is the probability that you would see a
minor

\>ESD in a lighted production facility? What is the probability that you

\>would see a spark discharge from the fiber core to the roller through
the

\>opaque cable jacket in the dark? in a lighted production facility?

\>

\>What is the effect of up to 3% water, an unknown percentage of

\>n-methylpyrollidone and an unidentified cure state upon the
conductivity,

\>dielectric strength, and dielectric breakdown strength of the
polyimide

\>coating on the fiber under all of the possible cure conditions and

\>processing conditions at BICC General?

\>

\>Furthermore, the presence of absorbed water at up to 3%,

\>n-methylpyrollidone, and HF at unknown concentrations present in the

\>partially cured polyimide, the electrical properties of the film will
not

\>be the same as the pure, properly cured polyimide under laboratory

\>conditions. It is quite reasonable to actually expect a limited

\>conductivity of the film based upon the ionization of the HF under
these

\>conditions.

\>

\>Based upon the fact that most electrostatic field meters are designed
and

\>calibrated based upon an assumed infinite plane potential source, can
you

\>provide a representative field strength map in three dimensions for
this

\>system?

\>

\>Based upon the fact that there is continuous movement in the system,
the

\>system is electrodynamic, with an undefined charge generation rate. If
no

\>discharge occurred, the cable would not be at a given potential, but,
would

\>rather generate charge until either coronal discharge occurred or the

\>machine was stopped.

\>

\>As the carbonaceous coating on the fiber is known to have a
resistivity of

\>approximately 600,000 ohms/meter, the existence of a potential field

\>difference on the order of 12,000 V across approximately 0.8 M will
result

\>in a significant depression in the potential through transport of
electrons.

\>

\>To support the 12,000 volt potential difference, across the 480,000
ohms

\>resistance requires 25 mA of current. Although I do not have a
quantitative

\>relationship for the current dissipation rate of the SSQ cable, 25 mA
seems

\>a bit too large to be dissipated by surface dissipation and random
charge

\>dissipation events.

\>

\>Would it be reasonable to assume that electric field should be a
function

\>of the rate of cable movement? Would it be reasonable to assume that
in

\>steady state operation that one could expect that two electrostatic
field

\>meters should read within one order of magnitude, or at least the same
the

\>same polarity of charge. Looking at the data from that test, it is
readily

\>apparent that either one or more the meters used in the testing was
out of

\>calibration, the meters were being used improperly or that the

\>electrostatic charge was not static, and that ESD was occurring.

\>

\>It is not reasonable to assume that the simplifying assumptions made
in

\>your calculation are valid. The inconsistency between meter readings
show

\>that. In the absence of adequate materials property variability data,

\>consistent electric field data with variability, reasonable electric
field

\>modelling, reasonable modelling of the charge flux, reasonable
measurements

\>of the potential between the carbon coating and the rollers and
evidence of

\>a lack of electrostatic discharge in any potential operational case,
rather

\>than a lack of evidence in one case, I would suggest withdrawing the

\>argument for there being no possibility of electrostatic discharge.
Lack of

\>evidence is not evidence of a lack.

\>

\>John S. Canham, Ph.D.

\>

\>

\>At 09:30 AM 3/14/00 -0800, Craig Mueller wrote:

\>\>Dale,

\>\>Yes, I did get a chance to present our experiments and analysis on
the

\>\>Electrostatic Discharge Damage ESD issue. My main point is that the

\>voltages

\>\>required to break down the polyimide are quite large and exceeds the

\>strength

\>\>of the electrical fields we measured at BiccGeneral last fall.

\>\>

\>\>As you recall, Jeanette Plante and I measured the electric fields
that were

\>\>generated while the re-spooler was operating at speeds of 20 and 50
m/min.

\>\>The maximum field difference that I measured between the two pulleys
of

\>\>concern was 4500 V/in. Note the measurement is in volts/inch and
does not

\>\>imply that there is 4500 V across the polyimide. The static problem
shows

\>\>that the field inside the polyimide is reduced by the dielectric
constant

\>\>over that which is measured outside in the air. That detail is
really

\>\>irrelevant as the dielectric strength (or breakdown voltage) is
given in

\>air,

\>\>not inside the polyimide by Dupont as 4000 V/mil. That value will
vary a

\>\>little with thickness and thinner layers will tend to have higher

\>dielectric

\>\>strengths. From our experiments, we now know that the polyimide
coating

\>on

\>\>the fiber breaks down at relatively high voltage, 3900 V (across 15

\>\>microns). That corresponds to 6500 V/mil a little higher than the
Dupont

\>\>value. But then again, the 4000V/mil represents an average over
several

\>\>different thicknesses and the dielectric strength tends to increase
in

\>\>thinner layers. Note that the fields measured at your facility were
4.5

\>\>kV/in and below the breakdown strength of the air (20-77 kV/in).

\>Otherwise,

\>\>we would have observed the pulleys arcing through the air to the
re-spooler

\>\>chassis. Converting the measured fields to V/mil, I get 4.5 V/mil
and a

\>\>factor of 1000 below the dielectric strength of the polyimide.
Hence,

\>based

\>\>on the measured data we have obtained thusfar, I cannot conclude
that ESD

\>\>damage to the polyimide coating has occured during the re-spooling
process.

\>\>

\>\>To verify that conclusion, I think it is a good idea to proceed with
the

\>plan

\>\>of running the uncabled fiber through the cabling process. Those
details

\>are

\>\>now being worked out and will likely be a topic of discussion during
the

\>\>Wednesday telecon.

\>\>

\>\>Craig

\>\>

\>\>

\>\>

\>\>

\>\>

\>\>DZevotek@BICCGeneral.com on 03/13/2000 11:11:00 AM

\>\>To: Craig Mueller/West/Aerospace/US@Aerospace

\>\>cc:

\>\>Subject: Summary

\>\>

\>\>

\>\>Craig,

\>\>

\>\>I am sorry I had to leave before you where able to make your
argument

\>\>concerning ESD. Did you have enough time to present any information?
I

\>\>know you are busy, but could I get you to summarize your opinion of
the TIM

\>\>last week (especially the information presented after I left). As
you will

\>\>see by an email I will forward after this message, I think there are

\>reasons

\>\>to believe that we need to do a great deal more testing before we
can

\>\>conclude anything about root cause. Alan English from Dupont has
some

\>valid

\>\>arguments. I am not a scientist, nor a chemist, therefore I have to
rely

\>on

\>\>the opinion of others. The one question I never got an answer to
last week

\>\>was if John was able to \'sniff\' any HF while handling the OC-1260.
I will

\>\>send him an email asking this once again.

\>\>

\>\>Let me know what you think!!!

\>\>

\>\>Best regards,

\>\>

\>\>Dale

\>\>

\>\>

\>\>

\>\>

\>John S. Canham

\>

\>

\>

\>

\>

\>

\>