D2 Injector installed on fusor - photos & notes

[MCL]

Hi. I thought I should post this update. I've completed installation
of the deuterium injector module on my fusor, and made some
other enhancements, as well. I am monitoring for any xray
shine-thru with a Cenco geiger counter and associated GM tube.
(My check source is a radium-illuminated wrist-watch - which
sends the counter into a blizzard of clicks - otherwise, the
background count is 4 to 8 counts per minute.) No evidence
of any shine-thru noticed to date, even at 30Kv and 50ma.

Also, I have configured an array of ceramic resistors, to give
a 500,000 ohm load, which allows my power supply to provide
up to 30Kv at 50ma. (Resistors get quite hot at this level).

Further, I have installed a small USB-port type video camera
to monitor poissor activity, and allow image capture for analysis.
(This is also much safer than trying to press my face up to a
running fusor and see and photograph what is happening!)

I've attached several pictures:
- The original D2 injector module. When I installed this,
I reconfigured it slightly, based on how the middle valve
actually worked.

- The fusor, with D2 injector installed.

- A high-res shot of the containment grid, at 5Kv, and
20ma, with about 15microns of vacuum indicated on the
thermocouple gauge. The transfer plasma (bugle-jet) is
dramatic.

- Five pictures captured from the little USB-port video
camera I have attached to the fusor to monitor activity
inside the reaction chamber. Note how the size of the
poissor increases, and the shape of the transfer-jet of
plasma changes

a) 20 microns vacuum, 3Kv, 4ma indicated
b) 20 microns vacuum, 7500v, 12ma indicated
c) 20 microns vacuum, 12500v, 20ma indicated
d) 20 microns vacuum,. 20Kv, 32ma indicated
e) 18 microns vacuum, 30Kv, 50ma indicated

I've suffered a setback with my diffusion pump. It seems to
have injested metal filings from work I did attaching the bellows
to the chamber, and fried the heating element. All the vacuum
pressures are developed by the rotary-vane pump only. (I am
working on a repair to the diff. pump - I'll post details if it works!)

- Mark Langdon
July 5, 2006

[Richard Hull]

Nice work, on the injector system and fine images, too.

From just looking at those shots, you will need a lot more vacuum work done as those images look like 40-80 torr or more.

This explains the huge currrent at very low applied voltage.

Ideally, you can't have a bugle jet or any hard formed jet and be doing much fusion based on my experience.

Most fusors that are really fusing show a small central poissor with either no star rays or many very thin, tenuous ones.

In spite of the Farnsworth team's study of visual presentation, (they concluded visual appearance means nothing), I and most fusioneers can tell you when you are NOT fusing.

Admittedly, a nice looking star can be made at 18kv or more at currents that mime a true fusion operation with just air in the chamber, but an accomplished fusioneer can sure recognize non-fusion conditions at sight.

I assume you have a secondary pump, (diff pump or the like)?

If not, your primary pump isn't hitting a low enough vacuum to do fusion.

I remember in demo fusor I, I used an old wornout Welch 1400 and it just would not pull below 30 microns in the chamber I was using, or at the head. In fusor II, I finally used a good condition 5CFM Precision pump and got an "air star" in the bell jar. This was also the first unit I had to do fusion with D2, though I do not claim it as it was to low to rise out of what I felt was the detector noise floor.

I was shsocked as a small chuck of glass popped off the inside of the bell jar due to e-beam bombardment! That freaked me out and I quit the bell jar. Within 3 months, I had fusor III doing real, easily detectable fusion in a proper SS spherical chamber.

Good luck in your continued quest to do fusion with your system.

Richard Hull

[MCL]

Hi Richard;

Thanks for the information, and the encouragement.

I realize that I need to get to a much better vacuum level. The pictures here are around 20 to 30 microns - really above the
level where fusion can be expected to occur, as you indicated.

I had a working diffusion pump, but the heating element has
burned out, and quite destroyed itself. I have tried a repair, but
it was not effective - so I am seeking either a replacement for
the diff-pump, or a turbo pump. I ran the bid up quite a bit
on the one on Ebay today... but Duniway will probably take it..

On the other hand, in for a penny, in for a pound. I may dig
a bit deeper.

- Mark

[MCL]

Hi;
Here are some additional pictures, taken in low-res mode
with a small video camera attached directly to the fusor.
Pressure is around 15 to 17 microns, as reported by two
different TC gauges (thermocouple). A second, cold cathode
ionization gauge reports around 9 x 10-4 Torr, but this is
inaccurate I believe. My diffusion pump has failed, and is
not in circuit, but the Welch rotary vane pump was run for
many hours, and the chamber was baked (to a limited degree)
with a heating element to at least reduce moisture, since the
equipment is located in a basement.

I am perturbing the poissor and transfer jets with two large
magnets, one placed directly on top of the fusor, the other at
90 degrees, on the right side. I have injected D2 into the
chamber, and noticed the chroma shift in the poissor from
blue to red. As Richard has suggested, the pressure is still
too high to expect any measurable fusion at all. I need to
achieve at least an order of magnitude better vacuum in the
reaction chamber than I have now, before I can expect to
begin to detect any neutron scattering.

But I am interested in just sussing out the orders of magnitude
involved in the various input parameters at this point, and I was
interested in how an asymetric magnetic field applied to the
process underway inside the asymetric containment grid will
operate under changes in voltage, current, pressure and D2
injection.
The jpg files are small, and made by dialing down the
exposure control on the camera software, so that the
scattering action becomes somewhat visible. Ultimately, I
am interested in determining if "pinching" and/or focusing both
poissor activity and the ion-gun beam can have any measureable
effect on the ultimate neutron output.

Pictures are:
a) Poissor_perturbed_by2magnets_17micron_2000v_2ma
b) Poissor_2Tjets_mag_perturbed_3500v_5ma_16micron_D2
c) Poissor_Tjet_mag_perturbed_20Kv_35ma_17microns_D2
d) Poissor_Tjet_mag_perturbed_30Kv_50ma_17microns_D2

- Mark

[Richard Hester]

FYI, Duniway stocks a lot of the common heating elements for diffusion pumps. If you call them up and ask nicely, they can probably tell you what heater your pump takes, if you know the brand. They have a lot of archival information on obsolete stuff. A diff pump heater element is a lot cheaper than a turbo...

[DaveC]

If only the heater element is burned out and the heater block is not deformed, you can probably find the proper sized catridge heater(s) for it. If the heater block is also warped or partially melted, you can make a new block from aluminum and bore it for the cartridge heater(s), if you have access to either a Mill or a Lathe. You would need to know the heater wattage, however.


Dave Cooper

[UG!]

i think i agree with Richard Hull on this one, that you have more preasure than you think here. with my turbo switched off, and just my single stage rotary pump, the preasure drops through the fan-out plasma jet stage and i get a single thin plasma jet and a small resonably well defined poissor. i would say you have a leek, but then you are pumping through a very long flexy tube. you can probably improve the vacuum considerably beffore repairing or replacing your diffusion pump.

Oliver

[Richard Hull]

Yor pressure is still rather high, I would say in the 30-40 micron range.

I did a lot of work in fusor II with large, very high energy product NdFeB magnets and placed some interesting video of my pinching the plasma at about 10-15 microns on my first and second fusor video tapes.

It really amounts to little more than what an ion pump does, in effect. It just cruds up the chamber and temporarily reduces the pressure through this process. Very strong field are needed to see significant effects.

Richard Hull

[MCL]

Hi folks;
Thanx for the info. I concur about the magnets acting like an
ion pump.

I noticed an interesting non-linearity. Tonite, I ran the rotary vane
pump for several hours, and the 2 large magnets have been in
contact with the chamber for several days. Of the 4 pictures
posted on July 8th, the last was at 30Kv, drawing 50ma, at a
pressure indicated of 17 microns - possibly higher at the
chamber, as I have about a 4 foot bellows connecting the
vacuum system and the chamber. Previously, on July 8,
I could not run the fusor at 30Kv for more than 5 or 10 seconds,
or the array of current-limiting resistors would start to smoke,
as I was drawing 50ma indicated on my power supply.

Tonite, with an indicated pressure of 12 microns, I could run at
30Kv (the limit of my power supply volt meter), and show only
27 ma of current drawn. This is almost half of what was
evident on the July 8th 30Kv photo. The poissor appears
different, also. I have attached a photo from the low-res camera,
which shows the 30Kv, 27ma, 12 micron run - which could be
maintained, although the resistor array does become quite
warm. I also could inject D2 - running the pressure indicated
up to over 30 microns - but it would slowly return to the 12
micron level, after about 4 or 5 minutes. Note also that I had
to dial the exposure way down on the camera, otherwise the
poissor appeared as just an indistinct white ball. Probably
not any detectable fusion yet, but I am getting about twice
the background count on my geiger-counter (40 CPM versus
15 to 20 CPM for July 8th) (Note: I have the Geiger ctr set
to about 800 volts on the GM tube - a fairly sensitive setting,
which makes the counter buzz dramatically, if brought near
a radium-dialled watch, which I use a my check-source)

I hope to be repairing the diffusion pump soon. The original
heater element was a ribbon of nickel-chrome foil, seperated
by a fibreglass ribbon. Steel particles got injested into this,
probably from my machining the end of the bellows (oops!), and
they caused it to short out and burn the ribbons in several
places. I plan to construct a rigid element, held in position
by ceramic disks, made from nickel-chromium wire, and then
powered by a variac - slowly and carefully ...

Once I restore operation of the pump, I will need to develop
a method to detect any evident neutron field - if there is one to
detect. Richard, I recall a post in which you described a
bubbles-in-liquid device for neutron detection, marketed by a
Canadian company. I will rummage about and find the post,
but I wondered if you found that this device reported results
that correlated with your other detection methods? Did it seem
to work well? Was it a detection method that could be relied
upon, in your opinion?
Thanx for any info.
-Mark Langdon

Picture is: 30Kv, 27ma, 12micron indicated, post-D2 injection,
with camera exposure set about 30% of normal.

[Richard Hull]

This is not the forum to talk detection, but the bubble detector is the last word, it is virtually infallable. It is slow to respond by click-click counter standards and you will not record delicate incremental levels with it, but you will record real fast fusion neutrons, regardless of other particles or electrical noise present and nothing else.

The He3 counter is the best for detecting small incremental fusion level differences in real time, on the fly.

The bubble detector tells you what actually happened and how your fursor does over time.

Basically, if you have five detectors..... Scintillation, BF3, He3, GM and a bubble detector, and all are known 100% functional and you place them in front of a fusor and all the counters roar during operation, but not one bubble appears in the bubble unit over time, then all the electronic counters reported falsely and you did no fusion at all. The bubble detector is that good. It detects fast neutrons and nothing else.

Right now, at this point in time, I own 12 different neutron counter systems. I would throw all in a waste basket right now if I were personally guaranteed that for as long As I live i could have continual access to and He3 counter and a fresh 30 bubble/mrem fast neutron bubble detector. This is all anyone needs.

Richard Hull

[MCL]

Thanx Richard, for the information on the bubble detectors. I've
downloaded the material from BubbleTech Industries, and even
managed a brief discussion with their Director of Research today.

They seem a pretty smart little group, and their location at Chalk
River puts them in the centre of the action for the type of research
and production they are doing, as far as Canada goes. Chalk
River is the site of Canada's first research reactor, and there is
still a significant Government-funded atomic research
establishment in that remote northern Ontario town. I recall in
public school studying all about Chalk River, and the various
exciting events that took place there at the beginning of the
"Nuclear Age" in the 1950's. For those who don't know the
story, the AECL research reactor, (the NRX), experienced a
complete meltdown in December of 1952. We read all about
it in grade-school in the 1960's, most especially, the details of
how the whole mess was cleaned up, with no lost of life, with
the research reactor being put back into service and run safely.
And that remained the case for another 40 years, before it was
finally shut down in 1992. But, I digress...

Still no luck with my diffusion pump. My attempt at repairing the
heater core was not successful (actually, an attempt to redesign
the heater, using ceramic spacers and ni-chrome wire from an
old toaster..!). I can heat the oil, but not at the right rate to
drive the pump correctly. I can create a much better vacuum
just by several hours running of the rotary vane pump with the
gas balast vent closed, than I can by involving the diffusion
pump. The best I have been able to achieve is 12 to 14 microns
as indicated on the thermocouple gauge, which is probably an
order of magnitude too high to do any detectable fusion. But I
am close, and have been testing the limits of the power-supply
and the D2 injector operation. And I will be ordering a couple
of BTI "Defender" model (from Bin 33 - most sensitive) detectors
from BTI tomorrow. My attempts at acquiring a budget-priced
turbomolecular pump have not yet been successful, but I have
another idea for repairing the diffusion device, with some heater
tape from VWR, which seems to be pretty close to what I took
out of the old pump, in terms of wattage and form (fibreglass
wrapped foil heating element).

I have attached three low-res pictures, very small, easy to
see with narrow bandwidth (I use a dial-up modem link
for all my internet access, so I appreciate a small-footprint
data-file more than most..

The magnets have been removed. There are 500,000 ohms
of current-limiting resistors between the fusor and the HV
negative output from the power supply. Power was run up to
a level where it pinned the meter, which runs up to 30KV, so
I estimate 35KV. Current indicated was between 22 and 24
milliamps. Exposure was reduced, but colour balance remained
the same for all pictures. Sharper and better focus than previous.

Pictures are:
1) No D2 yet, vacuum pump operated for about 5 hours,
14 microns indicated by the TC gauge. 35KV at 22ma,
with 500K ohms current limiting resistors in circuit.

2) Post D2 injection. Note red hue. D2 injection causes
immediate, instant change in colour and shape of poissor
and transfer or "bugle" jet. Also, TC gauge reports an
almost immedate rise to about 30 microns. Pressure
holds at this level, and then slowly returns to 13 to 14
microns after about 4 to 5 minutes.

3) About 7 minutes after D2 injection. TC guage reports
12 microns, 35Kv, 24ma, reddish hue gives visual
evidence of some remaining D2. This last picture is
interesting, as it shows the shape of the transfer jet,
that links the poissor plasma with the outer grid region.
One of the results of using the spiral-shaped containment
grid seems to be that there is a secondary mini-poissor
that sits just at the base of this transfer jet. It is best
seen in this picture. So far, there is only one t-jet
of this type at any one time, though it hops about the
grid every now and then.

Oliver, I am impressed by your images. Your red glowing
grid is more along the lines what should be seen. They jive
nicely with what the Univ. of Madison folks grid looks like
when at operating voltage. The big roiling ball of plasma that
is evident in my reaction chamber suggests too high a pressure
level. But I am intrigued with what appears to be the small
poissor-daughter that can be seen in picture three at the base
of the plasma jet. Has anyone seen a poissor-daughter like
this in other fusors when operated at "bugle-jet" pressure
levels?
- Mark Langdon

[Richard Hull]

Your poissor is very large! It nearly touches the grid! This is not normal in most fusors and I would imagine the bright bulgewhere the jet and poissor connect is related to its proximity to the grid wires. The possior I see in image three is not round. It is egg shaped, or so it appears.

All normal poissors at operating pressures are very small and very close to being a perfect sphere.

I can't explain your results unless your grid is under 2cm in diameter.

Note.... I have seen a poissor and jet POINT to a leak in the chamber if the leak was severe enough and the pump slow enough. I would look in the direction of the jet and egging of the poissor for a possible leak.

Richard Hull

[UG!]

thanks, i am flattered by the UoM comparison, i don;t think i'm quite in there legue (yet ) the small bright blob at the base of the plasma jet is fairly standard and indicates the preasure is getting slightly lower. it will become more defined, beffore fadeing away, leaving you with a straight beam like in my pics. Adam Szendrey did a very nice video of discharge dureing pumpdown a littly while ago, you may want to look at that of you havn't seen it already, theres a link in one of his posts.

Oliver