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Alamos
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--
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tQAIF-4D~Ws
--
I
TRITIUM PRODUCTION FROM
A
LOW
VOLTAGE
DEUTERIUM DISCHARGE ON PALIADIUM
AND
OTHER
METALS
Thomas
N.
Claytor, Dale
G.
Tuggfe, and Damon D. Jackson
DISCLAIMER
This
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mendation, or favoring by the United States Government or any agency thereof. The views
and opinions of authors expressed herein
do
not necessarily state
or
reflect those. of the
United States Government
or
any agency thereof.
Fifth International Conference on Cold Fusion
Monaco, and Proceedings
of
Low
Energy Nuclear Reactions
April 9-13,1995, June 18,1995
(Full Paper)
1
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document.
TRITIUM
PRODUCTION
FROM
A
LOW VOLTAGE DEUTERIUM DISCHARGE
ON
PAILADIUM
AND
OTHERMETALS
T.
N.
Claytor,
D.
D.
Jackson
and
I).
G.
Tuggle
Los
Alamos
National
Laboratory
Los
Alamos,
NM
87545
ABSTRACT
Over the past
year
we have
been
able
to
demonstrate that a plasma loading method produces an exciting and
unexpected
amount
of
tritium
firom
small
palladium
Wires.
In
umtrast
to
electmchemical hydmgen
or
deuterium
loading
of
palladium,
this
method
yields
a reproducible tritium generation
rate
when
various electrical and physical conditions
are
met.
Small
diameter
wires
(100
-
250
microns)
have
been
used
with gas pressures above 200 torr
at
voltages and
currents
of
about
2000
V at 3-5
A.
By
carefully amtrolling the
sputtering
rate
of
the
wire,
ruus
have
been
extended
to
hundreds
of
hours
allowing
a
significant
amount
(>
10’s nCi)
of
tritium
to
accumulate. We
will
show
tritium generation
rates for deuterium-palladium
foreground
runs
that
are
up
to
25
times
larger
than
hydrogen-palladium control
experiments Using
materials
fn>m
the
same
batch.
We
will
illustrate the
difference
between
batches
of
annealed
palladium and
as
received palladium
firom
several
batches
as
well
as
the effect
of
other
metals
et,
Ni
Nb,
Zr,
V,
W,
HQ
to demonstrate that the tritium generation rate
can
vary greatly hm batch
to
batch.
1.
INTRODUCTION
We
will
report
on
our
tritium generaton
results
fiom
a palladium wimplate configuration
subjected
to
periodic
pulsed
deuterium
or
hydrogen plasma.
This
contiguration
is
repduciile
within
a
batch
and
produces
a
measurable
amount
oftritium
in
afmdays
As
in
other work
in
this
area,
it
has
been
found
that
the
output
is
verybatchdependent
and sensitive
to
material
impurities
that
prevent hydriding.
As
in
our
previous
work‘f,
all
tritium
data
was
obtained
6rom
several
batches
of
100
or
250
mimn
Wire
and
250
micmnthick
plate
fium
J&M
or
Goodfellow
metals.
In
these
experiments most
of
the
tritium
data
was
obtained with on-line tritium
gas
monitors.
Several
times,
the
gas
was
oxidized
andtestedwithascmtillationcounter.
Some
have
criticized the
detection
of
tritium
because
the
signals
seem
to
be
(a)
insignificant,
@)
tritium
is
ubiquitous,
and
(c)
the palladium
metal
is
subject
to
vile
tritium
amtamm&
-on.
Themagnibdeofthesignals
discussed
in
this
paper
m
mdti-sigma
and
an
somefimes
over
a
hunddtimes
the
tritium
backgod
m
the
supply
gas.
Furthermore, the
rate
of
tritium evolution
in
the
sealed
system
may
be
the
most
sensitive
and
rapid
mdicator
of
anomalous
nuclear
behavior
in
devterided
metals.
As
such,
it
is
well
suited
for
pdc
investigations.
We
will
briefly
discuss
the
possl’be
avenues
for
amtammh
~onand&owthateachisnegligiile,ormtaficbr,
inthe
experimentsdescrii
2.
MATERIALS
Forthiswwk wed Cryogenic
Rare
Gases
deuterium
99.995%
that
has
90
pCiA
of
tritium,
and
research
grade
hydrogen
with
no
delectable
tritium
(<
25
pCi).
The
major
impurity
in
the
deuterium
is
€&
(0.005%) (He <lppm).
A
total
of
74.2 g
of
palladium wire/powdaKoil was
used
in
plasma experiments
descrii.
in
this
paper.
Ofthat
mount,
8.6
g
was
used
in
Various
hydmgen
or
deuterium
control
experiments.
The
palladium
has
been
checked
for
tritium
Cantaminaticmbytwo
hdqxdent methods (heating
in
hydmgddeuterium
and€&
plasma).
Much
of
the
palladium
has
been
subjected
to
rigorous
metallographic
and
impurity
analysis
The
impurity
levels
for
the
wires
(Johnson
Matthey
Fbabmic, Goodfellow)
varied
firom
the
specification
sheets
and
were
in
the
60-
150 ppm range (mostly
Cu,
Fe,
W
and
P)
rather
than
the quoted values
of
5-10 ppm.
Most
wires
were
as
received,
but
several
wires
were mealed
in
air
(at 850°C
for
2 hours)
or
stress
relieved
(600°C:
for
4
minutes)
in
air.
Some
of
the
wires
(mostly
Jaw,
when
wrapped
on
a
white
macor
cer(imic
spool
and
heated
(to
600°C)
left
brown
diffuse
deposits
(50
cm
or
more!
in
length)
or
black
diffuse
spots
(1-3
mm
in
length). The
two
batches that showed the
most
tritium
did
not yield the black
spots
but did leave light,
small
amounts
of
the
brown deposits.
Three
batches
of
palladium were
used
for
the
plate,
thi
lirst
batch
of
220
micron
thick
foil
was
mealed
at
850°C
for
2 hours at
lob
torr before
use.
A
second
batch
had
a Wmt
impurity
analysis
hm the
first,
but was
annealed
in
a
sirnilat
manum, the third batch was
used
as
received
and
had
a difkrent impurity level hm the
first
two
batches
(dthough,
all
three
plate batches
had
total
impurities
in
the
350-500
ppm range, mostly
Pt,
Au,
Cu and Fe).
Wire
from
five batches
(lots
W13918, W06528,ZO114,
NM
35680,u)293,
GF5140/6) was obtained
firom
Johnson
Matthey
and Goodfellow Metals and one
length
of
wire
was supplied by
Ben
Bush.
Only
the
Goodfellow batch and
J&M
(W13918)
showed large
(8
to
102
nCi)
amounts
of tritium although the other batches of
J&M
and
Ben
Bush
wire
produced
small
amounts
(-1.5
to
6
nCi
total
per
run).
Tritium Contamination
in
the palladium
wire
and
plate was tested by
two
independent methods sputtering of
the
wire
in
a hydrogen
plasma
atmosphere
and
heating
of
the
wire
or
plate
to
either
260
or 800°C
in
deuterium or
hydmgen.
No
evidence
of
tritium
(to
within
experimental error
-
0.3
nCi)
Contamination
was found
in
the heating
expiments
with hydrogen. The Goodfellow
wire
was
tested
for contamination (with
null
results
-
0.3
nCi)
by heating
to
280°C
sections
(0.1
g)
of
wire
taken
between
wire
samples
shown
to
produce tritium
in
the experiments.
In
our
previous
woe
we were able
to
set
a limit of
0.005
nCYg obtained with 'He
detection
of aged palladium samples
from
a
Werent
lot
Also,
in
an
extensive independent' investigation of palladium wire,
several
hundred
wire
samples
were
tested
and
no
tritium contamination
was
detected
The
purity of the wire
used
in
these
experiments
also weighs against,
ubiquitous,
inbinsic spot
contamhation,
although the appearance of the
black
and brown
deposits
indicates that spot
and
distributed impurities
can
be
present
3.
APPARATUS
Shown in Figure
1
is
one
of
two
stainless
steel
gas
analysis
loops
containing a
1.8
liter
ion
gauge and
a
3
10.9
cc
calibration volume. The atmosphexic,
ion
gauge
and
sample pressure
(0.2%),
Femtotech and room
temperatures
(O.l°C)
are
recorded
on
a
computer
log
at
60
s
intends. The
pressure
drop
during hyddng of the
wire
and plate
is
used
as
an
approximate
indicator
of the
stoichiometry
of the
PdD,
Both
loops
have
a
heater
to
maintain
the Femtotech
(-0.03
nCi/l°C)
at
a
constant
kqmatwe,
an
integral
cold
trap,
and
there
are
valves
that
allow
the pressurization
of
the
cell
independent of the loop.
A
two
micron
flter
is
installed
at
the
inlet
of the
ion
gauge
and
at
the
outlet
of
the
cell
to
I
a
~~~ ~~
Figure
1.
Tritium dysis
systan
used
in
this
study
showing
the
oxidition
apparatus.
eliminate spurious
respanses
due
to
particulates,
To
eliminate the possibility of
oil
contamhation,
a molecular drag
and
diaphragm
php
is
used to
evacuate the
system
The Fatotech
ion
gauge
rejects
pulse
type
radioactive
events
that effectively
discriminate
againstradonand
cosmic
ray
ionization. The initial
background
drift
rate
in
the Femtotech was
0.002
nCih
to
0.006
nCi
but
after
exposure to the
cells
described
in
the
paper, the
drift
rate
increased,
and could
reach
as
high
as
0.01
nC&
In
order
to
return
to the baseline rate, it
was
necessary to clean the loop tubing and Femtotechs
halfway
through
the
study.
A hydrogen oxidation
system
was
built
as
a backup
test
for
tritium using a scintillation counter (Packard
1600).
Calibration
D,
gas with
25
nCa of tritium
was
used
to
test the
two
Femtotechs and the oxidation
system.
The
two
ionization
systems
agree
to
within
5%
of each other while the
scintillation
dts
are
within
the experimental
error
(0.3nCi) of the Femtotechs.
The typical arrangement
of
the
cell
allows
a
wire
to
sit
perpendicular
to and a
fav
millimeters above a circular
plate.
In
operation, the plasma
is
adjusted
so
that
it envelopes the whole wire
and
contacts
the plate at a
small
spot.
Typically, the plasma
is
light blue
(D29
with
areas
of pink
(D:
or
D').
At
high
currents
(>
5
A), a bright pink electron
channel forms that extends parallel
to
the
wire
fi-om
the base of the wire
to
the plate. Initially, the Pd wire is
25
to
30
mm
in
length and about one
mm
fi-om
the plate. The plate diameter
is
3.0
cm
or
1.8
cm.
4.
PROCEDURE
The procedure for a plasma
run
was
to
first
till
the
3.1
liter loop with deuterium gas at
600
torr
and obtain a
measure
of
the initial background
tritium
concentration.
With the
loop
drift
rate
measured,
the deuterium
was
circulated
through
the
cell
to
slowly
hydride the sample. The pressure in the
cell
and
the
loop
was
then
lowered
to the operating
pressure by pumping the
excess
deuterium
out
The
wire
was
pulsed negatively, at
20
ps
at
50
Hz,
with
currents
between
2
and
5
A,
voltages that varied
fhn
1500
to
2500
V,
and
cell
pressure of
300
torr. These conditions
reduced
the heating
in
the
cell
and
maintained
a
cell
to
ambient
temperature
difference
of
less
than
25°C
to
avoid
gross
dehydriding of the
wire
and plate. It appeared important
to
avoid
a
plasma condition
that
resulted
in
either
a
bright
pink
electron
channel
or
arcing
at
the
tip
of
the
wire.
After
a
few
hours of plasma
Operation
the
volhqpamnt
stabii
premnably
due
to
the
formation
of
5111811
cones
(10-20
microns
high)
all
over
the
dace
of the
wire.
After
20 hours, palladium
was
visiily
sputtered
onto
the plate. The
sputter
rate at
300
ton,
3.5
A,
was
about-2
k
The
cell
pressure
wasmonitored,
and
if
it
didwt drop
after
24
hours
(indicating hydriding), then
a
small
mount
of
COz
(0.75%
by
vol)
was
added,
which
would
initiate
hydriding.
At the
end
of a
run
the
pressure
was
iwreasedto
600
torr,
the
gas
was
circulated.
and
the
system
allowed to
equilibrate
for
about
8
hours.
Ifthe
reading
was
steady
and
COz
was
added,
then the
gas
was
circulated
through
the
liquid
nitmge~~
cold
trap
to
collect
any
water
and
determine
if
any
tritiated
water
was
present.
The
system
was
then
pumped
out,
the
cell
closed
o&
and
fie&
deuterium
added
to
the
system
after
a
couple of
flusha
with either
fresh
deuterium
or
air.
The
difference
between
the
Iksb
deuteriumand
the
deuterium
reading
after
exposme
to
the plasma
was
used
as
the
measure
of the tritium
content.
In
cases where
more
than
10
nCi
were
found,
the
palladium wire and
plate
were
heated separately
to
over
250°C
and
the
result
admitted
to
the
evacuated
loop.
5. RESULTS
A total of
65
plasma
Wire
experheats
were
performed,
12
ofthese
were
other
than
palladium
wire
and plate.
Twenty
experiments
were
nm
with multiple
Wires.
usually
3
Wites
buudled
together,
and eight
experiments
used
different
thickness
foils
25
to
125
microns
thick.
The
balance
ofthe
tests
were
done
with one
250
micron
diameter
wire
and
250
micron
thick
plate.
Three
hydrogen
plasma
experiments
were
done
with palladium plate and
wire
and
two
were
done
with platinum
wire
and plate. A
summafy
of
several
background
and
f-d
experiments
is
shown
in
Figure
2.
The
best
experiment, produced
102
nCi.
Plasmamus
3
and
4
deserve
some
detailedexplanation
since
these
produoedthe most tritium.
First,
(see
Figure
3)
cell
3
was
preheated in
order
to
drive
off
any
contamiuank
The
plasma
was
then
started
and the
tritium
generation
rate
was
0.15
nCi/h. Near the end
of
the
nm,
the
cell
was
twice
flushed with
deuterium,
which
caused
&e total tritium
(as
detected
by
the Femtotech) to
jump
up.
At the
conclusion
of the experiment the plate and
wire
(fiom
plasma
3)
were
heated,
insitu,
and released another
5.4
nCi.
In
order
to
resolve
whether
the
tritium
was
origiaating
in
the plate
or
wire,
they
were
separately heated
after
plasma
4.
The
wire
released
about
12.4
nCi of tritium while the plate
had
no
measurable
(<
0.3
nCi)
release.
A number of
Pt
and Pd
controls
were
nm
with
Qor
&.
Most
of
these
are
shown
in Figure
2
in
comparison
with the foreground
cells.
In
general,
drift
rates
with
the
plasma
on
were
in
the
0.004
to
0.01
nCim range. Not enough