FAQ - Bubble Fast Neutron Detector

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FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

admin note 160322: the previous link to bubbletech.ca has been 404'd. Search http://bubbletech.ca to see if you can find what you're looking for.



I include images of the device below.......

These are FLAT RESPONSE, FAST NEUTRON DETECTORS
200KEV - 15 MEV

I just checked with these folks, by calling and chatting with one of their physicists on staff, and the BD100R of the highest sensitivity is $75.00 . These produce 33 bubbles/mrem. (You MUST specify "33 bubbles/mrem", as they have these in graded sensitivities) This seems pretty cool. The stated accuracy for absolute integrated flux is +/-20% which is really very good.

Not so good is the "no-way-out" shelf life of 9-12 months, max. Also very bad, is the fact that this is a Canuck product and they hose you for an additional $30.00 U.S. for handling all the border/entry paperwork for a single dosimeter and an additional $30.00 Fed EX shipping fee. CAN YOU SAY OUCH! I also had to give our federal ID number here where I work. Probably helps grease the rails for entry and tax purposes. What the hell ever happened to NAFTA!!!

Note 2019: These puppies are now $250 including postage!!! Times change......... End edit.

I had to check this item out myself, so I fell on my sword and ordered one!

The shelf life is due to the drying out of the water based hydrogel polymer inside the tube. The unit is reset, (bubbles erased), by simple compression supplied by a screw mechanism on every tube. when not in immediate use, the device must be returned to its aluminum, cigar tube, storage device or the thing will not last even 9 months. (helps prevent dehydration.)

The unit is activated by removing from its storage tube and unscrewing the compressor mechanism. Measurement is made and the device read. Tightening down on the screw pops the bubbles and turns the tube off. The bubbles need about 10-30 minutes to go away, depending on age. This time increases with age, but not use. The tube ultimately fails when bubbles won't all go away, but can still be used for a while by just logging the bubbles present at start and counting the bubbles at end and subtracting. Ultimately, the bubbles will merge into big bubbles and the sensitivity is blown.

Another final "gotcha" is that the temp range is narrow. A warranted 10-30 deg C window is it for measurement and storage.

There is a no limit on the number of count runs during the shelf life. It is age, and age alone, that kills this puppy.

Lets do some figuring.

1mrem absorbed dose of 2.4 mev fast neutrons is created by an hourly passage of about 8n/sqcm/sec or about 2.8X10e4 neutrons through that square cm. This is 1 mrem for 33 bubbles. This means, on average, one bubble will be generated for every 872 neutrons impacting the tube/sqcm of surface, at range.

For a high sensitivity tube placed 20cm from the poissor outside a fusor producing 50,000 n/sec isotropic, one bubble would be created every 88 seconds. (someone check the math here).

The rate of production would go up linearly with emission rate, ie., 100,000 n/s would produce one bubble every 44 seconds @20cm, but vary as the square of the distance, ie, one bubble every 352 seconds for 50,000n/s at 40cm, etc.

This is pretty good for only 75 bucks + the outrageous shipping and handling. This would still beat most any other method except for a good BF3 or He3 setup. All peaks and valleys in production would be lost and smoothed out via the integrating nature of this dosimeter.


I could see these being a great check for fast neutrons provided there were enough of them around for a period of time. They could complement a counter. Still, there is nothing like the satisfying chirp of a counter when in a neutron field.

These would be THE ULTIMATE AND MOST FANTASTIC TEST FOR A RUNAWAY FUSOR. No bubbles - no runaway - your counter went screwy, instead...........lotsa' bubbles, you've got something going on................just a foam in the tube, kiss th' wife goodbye, but remember to post here about the experience and parameters before going off to die.

I was informed that the low end resolution (few bubbles) will blow the statistics by proportional amounts. ie, one bubble will not even be the 872 neutrons calc'd above but could be 2080 or 410. Two bubbles would narrow this error a bit and three or four would have much more meaning. (follows 1/n rule in statistics) Regardless, NO ORDER OF MAGNITUDE ERROR IS POSSIBLE.

Given a 10 minute run at the moderate rate of 50,000n/s that would load this puppy up to about 6 or 7 bubbles and I was told this is OK to within 35% absolute flux.

Another great thing is that with a one time purchase, you could develop a fixed indium foil activation scenario for your specific fusor and transfer cal so that one of these "bubble bottles" would be all you would ever need.

Many thanks to Sasha W. whose original URL posting spawned an expanded reply which morphed into this FAQ

******************* UPDATE 10/04/04 **************************

As promised, I am updating this post!! I have received my BRD-100R (33 bubble/mrem) detector and have attached two images.

The first shows the overall detector mounted at the fusor IV.
The second image shows a closup of the device and bubbles.

I set the device in contact with the weak source from the college and it gathered 38 bubbles in 3 hours. That is a total of 38/33 or 1.15 mrem dose. This makes the source a particularly weak 0.38 mrem/hr fast neutron source. Based on the fact that there are 8 neutrons per second per second passing through a 1 sqcm area per single millirem/hour This makes this source a 3 neutron/sec/sqcm source and the center to center separation of 2 cm would lead to a 4 pi rate of about 300 n/sec. (this is figuring in the tube geometry, etc.

Using the detector.................

Upon arrival, I freaked out as the device was filled with thousands of tiny bubbles and I couldn't get rid of them!!! A call to BTI confirmed that these are normal in the sensitive units and that upon exposure to fast neutrons, the real bubbles were massive by comparision and this turns out to be the case. (see the second photo to see the fine and the real counting bubble differential). Upon recompression following the above counting, the device cleared itself in under 20 minutes and was ready for another run.

**************************** UPDATE 10/06/04 **********************

Regarding Background:

A fantastic discovery is that there is no need to take a background reading with this detector!!!! I took the BTI detector to my upstairs lab, activated it and read the background for 5 hours. Not one single bubble appeared! This is fantastic news. Most high end fusor neutron data collection runs never last over ten minutes, at most! Thus there is no background detection check required with these devices. They must truly be in a neutron field of fast neutrons to even start to detect!

To those so disposed as to take in the full ramifications here, it means that by using this detector, you have a nearly perfect piece of neutron metrology, provided your fusor is really doing fusion! No electronic snafus, no batteries, no electronic noise issues, no false runaways, no background gamma, or cosmic issues. These things will not even detect thermal or epithermal neutrons common to all fast neutron fields provided those neutrons reflected or moderated are under about 50kev!!!

All of this was confirmed with another call to BTI and further discussions with a physicist there. He noted that these just WILL NOT count thermal or epithermal neuts!! FANTASTIC!!

Temperature effects:

There is a full temperature adjustment chart avaialable. At 41 deg F you are only reading at 1/2 the rate specified. At 68 deg F you are right on calibration. At 90 deg F you are reading two times higher than rating. Restated, for a 33 bubble /mrem BTI detector that would mean one millirem would be represented by 16 bubbles at 41 deg F, 33 bubbles at 68 deg F and 66 bubbles at 90 deg F. So, you must mind your temperature at time of data collection and put in the appropriate correction factor.

***************************************************************

I am now clearly recommending the BTI bubble detector as THE ONLY neutron detection method for fusor work that is totally bullet proof. Bottom line.......if you SEE bubbles you HAD fast and ONLY fast neutrons present. For $75.00 + about $50.00 worth of postage and entry paper hassles, you have your detector. This is especially nice if you are just going to kiss fusion and not take her all the way to the alter for life. BF3 units, etc. are hundreds of dollars for a known good unit. If you fuse and then move on, you have a device that might never be used again!

This bubble detector is the only suitable device for counting pulsed systems net or integrated activities.

More data will be placed in new posts later on this detector.

Data for those interested can be found at the URL above.

*******************************************************************************************
update: 3/3/17

IMPORTANT! Due to the rather short lifetime of these devices and their relative expense for the average amateur scientist and would-be fusioneer, it is highly recommended that no one here purchase the BTI dosimeter until they are actually finished with their fusor and have it working to some degree. (producing a plasma in a metal chamber at voltages in excess of 20kv and currents over 10ma in a deuterium atmosphere of 5 microns or greater.)

If you purchase before you have a, more or less, functional fusion device, you might just fail to do fusion, and while struggling to get the device updated to really do fusion, the BTI might go bad. Never, ever, start your fusion quest by purchasing a BTI bubble detector! It might be best to make it your last purchase.

*****************************************************************************************

update 11/27/19

The price of these things has soared to ~250 per each delivered Group buys are a way to shave of a few bucks if delivered to one point. (central guy making the buy. He then redistributes for wery small money.)
There is a question about intense pulsed neutron work. If you are doing this kind of work, (unlikely), you might check with BTI to see if gamma and x-rays due to a massive discharge might also create false bubbles. For regular fusors operated smoothly over many minutes, the BTI is a true reader of neutron dose. Not to worry.

Richard Hull
Attachments
Mega bubble.jpg
MVC-015F.JPG
Bubs.jpg
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Re: FAQ - Bubble Fast Neutron Detector

Post by Adam Szendrey »

Hi Richard,

Thanks for the FAQ on this "bubble meter".
Is there any possible way to rehydrate the hydrogel inside the tube? Or to refill it? Can such a gel be purchased separately?
Well i guess most of the cost of this tube is the gel inside.
If there would be a way to extend it's useful life it would be a fantastic ultra cheap fast neutron detector! Well even for a year it still is cheap :).

Adam
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

The answers are no, no and no. The mix is their secret. Carl Willis opined that it may be part of a planned death to keep selling the detectors, but I guess it is a natural chemical separation of the gel and a drying out of the polymer used. If it performs to half of their promises and one quarter of my expectations, it will be nothing short of incredible!

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: FAQ - Bubble Fast Neutron Detector

Post by Jon Rosenstiel »

For a detailed description of the bubble detector see:

Knowles (Radiation Detection and Measurement, third edition). He devotes three pages to the "Superheated Drop Detector". (Bubble detector).

Jon Rosenstiel
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

New materials come on the scene constantly and the bubble detector has been around for years as a gross exposure dosimeter. However, it has never had the sensitivity of these new devices. New polymer? New superheated vapor? Who knows? They are not telling deep specifics regarding materials or processes.

I seem to remember at least 4 years ago, on the old "songs" list, going over a bit of this in a thread. I called another organization and got pricing, but the sensitivity was not all that impressive.

I am certainly eager to get my hands on Chalk River's best bubble detector.

As an aside, I was told that they can make 100 bubble/mrem units to special order with very special pricing to match. However, they have found a considerable variation in these .01 mrem/bubble units and note that their 33 bubble unit is the point where repeatable, consistent, recording is possible without heroics. I think 0.033rem/bubble is fine with me.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

I just updated the original post 10/06/04 with Fantastic background detection news. You must check this out!

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: FAQ - Bubble Fast Neutron Detector

Post by 3l »

Hi Richard:

Would this bubble system work well on pulsed fusion devices?
Could it be used in one place?
If so I will probably get one.

Happy Fusoring!
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

Re-read the original post. (near the bottom) I note specifically that this is the ONLY detector that will give a fully creditable neutron report on a pulsed device.

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Re: FAQ - Bubble Fast Neutron Detector

Post by 3l »

Hi Richard:

I see it now.
Cool.
When you talked with the Canadian firm would they only deal with companies?
I have a company but it would be nice to order as an individual too.

Happy Fusoring!
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

They should certainly sell to an individual.

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Re: FAQ - Bubble Fast Neutron Detector

Post by Starfire »

Richard - checkout;-

Admin note 160322: it appears that the item previously linked here is no longer available. However, http://bubbletech.ca remains a viable domain, see if you can search for what you're looking for there.
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

I have talked with them about the defender...... 1000 bubbles/mrem!!!!!!

For only $500.00 and it goes bad in a year or two.

They note that its indicating bubbles are much smaller than the 33 bub/mrem unit and are therefore harder to count.

I'll stick with what I have. More reports soon.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
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Re: FAQ - Bubble Fast Neutron Detector

Post by Frank Sanns »

This unit is also a good way to invision what the damage to your body would be like. That is the kind of damage that would be all through your body from the neutrons from a fusor at similar distance. In your brain, heart, liver, and in every cm^3 of your body. The good news is that the human body is very durable (but not indestructable).

Frank S.
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We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

Frank is 100% correct. We must not lose sight of the nature of the fast neutron. To get this dose, of course, you would have to lay on the fusor while it is running. Our fusors are very weak neutron producers even during the best runs. This is why we need sensitive instruments to detect and quantify them.

Nothing beats using the inverse square law to protect yourself. Distance, coupled with even moderate shielding makes exposure a non-issue for fusor operators.

Richard Hull
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

The more I use this 33 bub/mrem BTI bubble detector, the more I think ....ALL ......that is, 100% of all other detectors are just not worth owning.

The sole holdout that I would wish beyond the bubble detector is the super sensitive HE3 detector in its large tube iteration that I currently use with fusor IV.

Remember, I own virtually every form of electronic fast neutron detector that is out there and the above is a definitive statement by a long time user and fusioneer. Cold fusion work and the ultra low level neutron detection demands the He3 big tube units.

The average amateur fusioneer could never do any better than one of the BTI bubble detectors. With electronic noise, arc discharges, wiring running everywhere, coupled with haphazard and unstable operation, true neutron output can ONLY be followed with extreme accuracy by the bubble detector! All other detection methods suck to greater or lesser degrees compared to this low cost, no battery, no power, no noise solution.

Again the only way bubbles form in this puppy is in a real swarm of fast neutrons!!!! A deadly field of gamma radiation yield no bubbles. A reactor load of thermal neutrons yields no bubbles. Basically, no bubbles means........No fast neutrons and, thus,.....No fusion.

In a small flux of only 8n/sq cm/second you will see one bubble pop into existence every 110 seconds.

This is not to denegrate counters or systems used by others or myself in the past. It is rather a story of forgetting that noise ever existed, of forgetting about background counting and determination, forever, about saving approximately $500.00 over a rem ball, about not being fooled by balky instrumentation operated at the hands of an amateur.

I just removed the batteries from all the neutron instruments I own! I just won't be needing them in the immediate future now that I am armed with the NIM bin based He3 counter and the BTI bubble detector.

Bubble detectors used to be expensive, short lived, high flux only and messy to work with. Most of these disadvantages have disappeared. There are only two remaining issues.

First, and of the least concern, is the narrow temperature range of operation (~45 deg F to ~92 deg F) and the need to adjust readings based on ambient temp at time of exposure. (note - There are tempcompensated units avaialble...$$)

The big negative is that you need to spend about $120.00/year to keep a fully action ready BTI bubble device on hand. For those who work for a living and are not saddled with kids, a mortgage and two car payments, the $120.00 is chump change to be positive about neutron outputs in fusion devices. Admittedly, the guys at BTI said the time of valued usage varies from 10 months to 18 months based mostly on temperate storage.

Richard Hull
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Re: FAQ - Bubble Fast Neutron Detector

Post by Adam Szendrey »

Right now, the only, and single, disadvantage i see is the limited lifetime, otherwise it's really great, and rather cheap, and indeed an extremely reliable indicator of fast neutrons. Thanks for the info you supplied Richard.

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Re: FAQ - Bubble Fast Neutron Detector

Post by Verp »

This thread has me thinking about if it would be possible to make this sort of detector on my own. I just need to watch my tendency to get quixotic and take this beyond the area of diminishing returns. I once thought it would make sense to build a low whistle one octave below the standard D pennywhistle, rather than spend too much on a new one. The project got out of hand and I now own a drill press (not to mention all the various plastic and metal tubing for the body of the whistle) that costs more than one good high quality low whistle!

I have worked with gels in the past, through cooking and having poured my own agar based media into petri dishes and culture tubes. (I was making clones of local wild edible mushrooms I had collected.) I think some experimentation with the right gel will be needed to find the right ratio of liquid to polymer that is strong enough to prevent the liquid from bubbling, but flexible enough to bubble at the increased vapor pressure of the liquid caused by a high-energy neutron hit.

My first thought was to use agar, as that is readily available gelling agent, or other polysaccharide (sugar polymer) used to make growth media, but I realized even gelatin would work with a small bit of preservative that doesn’t mess up its ability to gel. If the vapor pressure of water isn’t high enough, another possible gelling agent is polyacryamide, which can handle many solvents that the natural gelling agents can’t and is available as an electrophoresis gel. It is polymerized in situ when the gels are made, but acryamide is a carcinogen and neurotoxin, complicating things.

The only reason my first thought was to use agar is that it is the gel I’m familiar with using at many different concentrations. The only reason it is preferred to gelatin is that microbes don’t eat it up as quickly. As I don’t want to grow things in the first place, I would use inexpensive gelatin in water with a bit of preservative if I was to make a very large detector. If a higher vapor pressure solvent were needed, I would make a small detector using polyacryamide. The gel used to make transparent candles might work, also. The liquid, I believe is kerosene or some other petroleum distillate, would probably be easier on the roughing pump than say water, if the pump was used to reduce the pressure in the detector.

Speaking of getting quixotic and going overboard, I was thinking of using a large gelatin or candle gel detector as the neutron shield of a high output reactor. The pattern of the bubbles around the fusor might give clues to the pattern of neutron emission. A concern might be if the detector were too deep, would the weight of the gel make the detector less sensitive toward the bottom? I might get around that by using less of the gelling agent at lower levels in the detector, but that might involve a lot of experimentation and may not work. I could just make the detector as discrete layers too thin to be strongly effected by the depth of the gel.

As far as figuring out the proper pressure to run the detector at, I would guess that an absolute pressure gauge that reads up to ambient air pressure could be used to find the pressure at which the gel starts to bubble. I would then use ambient air pressure to collapse the bubbles, and finally bring the pressure down to just above the pressure it bubbles at without high-energy neutron hits.

Rod
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Re: FAQ - Bubble Fast Neutron Detector

Post by Frank Sanns »

Rod,

You might try to use poly vinyl alcohol in distilled water to bring the viscosity up to a desired level. A little fumed silica (Cabosil) could be added to keep the gel in place after the bubble forms. It is a thixotropic agent that will gell fluids that are not moving. Once they move a little, the visocity drops only to jump up again when the movement stops. A little benzalkonium chloride (Bactine) can be added to stop microbial growth. For the low boiling solvent that will vaporize to form the bubble, I think butane was the choice in the early tubes.

Frank S.
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Re: FAQ - Bubble Fast Neutron Detector

Post by Verp »

Frank,

Thanks for the input. I am familiar with benzalkonium chloride as quaternary ammonium detergent or “quat” as the active ingredient in sanitizing cleaners (as well as in Bactine) so price and availability are not issues. I am familiar with polyvinyl alcohol as an ingredient in some insect specimen mounting media. I remember it was a real pain to get into solution, but seemed to have no real toxicity issues. If gelatin is cheaper than polyvinyl alcohol and works well, I will try that with the weakest solution of quat recommend as a biocide, probably the concentration used as an algaecide in lab water baths. I’m not trying to kill tough spores and viruses, just keep organisms from starting families in my detector.

If a low enough pressure will make the detector work with just a water based gel, I won’t worry about how much butane or other low vapor pressure fluid to introduce, getting rid of another variable.

My understanding is that a good roughing pump tends to remove material with a higher vapor pressure than the oil, especially with a good sorbent to keep the oil clean, so careful use of valves should keep water contamination of the vacuum system low when I pump down the detector. I could just use a large bellows or piston to reduce the pressure in the detector and simply make sure there is no air space when I first fill the detector.

Perhaps the right amount of fumed silica would be the maximum amount that doesn’t make the water too cloudy, then add just enough gelling agent to keep bubbles from rising and the silica from settling. I’ve seen Carbosil for sale as a thixotropic agent for use with fiberglass resins as a filler, so it shouldn’t be a big issue to get it for a reasonable price.

Fumed silica got me thinking about sodium silicate and silica gel as gelling agents, but I am just brainstorming. An inorganic gel would not support or be broken down by microbes, though.

I will work on this some more, maybe after getting closer to actually making neutrons.

Rod
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Re: FAQ - Bubble Fast Neutron Detector

Post by Alex Aitken »

"I think some experimentation with the right gel will be needed to find the right ratio of liquid to polymer that is strong enough to prevent the liquid from bubbling, but flexible enough to bubble at the increased vapor pressure of the liquid caused by a high-energy neutron hit."

Hmm. This was not my understanding of how the device worked. I was under the impression it was a suspension of droplets above the boiling point and under no extra pressure from the matrix. What's stopping the droplets from expanding is the lack of a surface to nucleate on. I was furthur under the impression that the point of the matrix was to keep the droplets seperate from eachother, seperate from the walls they could nucleate on and prevent the nucleation effect when it happens from spreading to the other droplets.

I suspect the chemicals need to be exceedingly pure from dust and solids.
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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

It's all a big secret and they aren't tellin'. Feel free to muddle along trying to "guess engineer" or "roll your own". All that remains is consistency and calibration. I figure the latter are fully 50% of the effort.

For a fact, they mass irradiate and "bin" each detector based on bubble numbers so it ain't even slighly precise at the manufacturing end. What you get is a carefully cal'd luck of the draw, pick o' the litter, bubble detector that is repeatable and reliable.

If you have a hot neutron source, (they used a chalk river reactor), the chemical know-how and access to ultra pure chemicals you should be able to make up a hundred of so and then irradiate them and "bin" them based on performance just as they do.
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Re: FAQ - Bubble Fast Neutron Detector

Post by Jon Rosenstiel »

Just got off the phone with these guys...placed an order for the BD100R, 33bubbles/mrem model. Should arrive here before xmas. (Maybe it'll be under the tree)?

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Re: FAQ - Bubble Fast Neutron Detector

Post by Richard Hull »

John,

Fantastic! You must report to us all the details once you put it to use. You WILL love it and hate it.

You will love it because it doesn't lie. You will hate it because it doesn't lie.

I found that after spending a mint and jumping through numerous hoops to obtain the finest electronic neutron detection system around for fusor IV , (He3 system), that the bubble device was much more reliable if not quite as sensitive. It is a snap and a no brainer to use.

My plus ultra He3 system is just clicking away like gang busters and with each upward inching of the voltage control the count is noticibly more active. At 29kv I am getting nearly 200-300 CPM with the He3 but the bubble detector is showing about 50-80,000n/sec., isotropic!

Damn it all! The truth will out.

Some tips when St. Nick drop the thing down the chimney.

Operate and store it within the temp range specified. keep it out of the fusor area until your fusor is cruisin' along at the point that you can satbilize it easily for a minimum of five minutes. Don't try for max output on you machine. Shoot for stability, though this is not actually madatory as the thing is a perfect fast neutron integrator. With stability, your actual final figure will be more representative of the entire run.

Once in your comfort zone with the fusor. Get a ring stand as used in chem labs with a test tube clamp and place the base of the BTS detector at least 4" away from the shell (to avoid radiant heating of the detector) and then open the pressure screw until the screw goes sloppy. (it will be retained).

Start a timer immediately and then run for a period that you like. Watch the bubbles pop into existance. Cool!

DO NOT LOAD THE THING UP WITH BUBBLES. End the count when the device appears to have about 30-40 bubbles in it. Note the time and total exposure period. immediately take it out of the fusor area.

Counting - the nightmare begins.

Surely you can count 30-50 bubbles??? Yes and No. You can count 5 times and get 5 different counts.........!! BTS recommends you have a buddy or others count and do a statistical reduction.

I have found that carefully and slowly rotating the device and counting as in a spiral staircase works for me. Log your result with pencil and paper and then screw the screw all the way back it to just good and snug. BOOM, the bubbles are gone. As age sets in, they will not flashout like when new and a few minutes will be needed to ready the device.

Enjoy! And remember us out here. Give a full report, especially personal comments, problems, delights and thoughts on the device.

Unfortunately, the device is so good that your rem ball might fall into disuse or be religated to backup or confirming actions.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Alex Aitken
Posts: 250
Joined: Mon Dec 08, 2003 5:33 am
Real name:

Re: FAQ - Bubble Fast Neutron Detector

Post by Alex Aitken »

This is probably making a very simple detector over technical but....

Ive heard of laser counters for the bubbles and they seem like rather technical devices. If a light was shined through the tube while in operation though, with the result being read by a photo cell wouldnt the apearence of each bubble result in a noticable change of level of the light output? If something monitored the apearence of each bubble that sounds easier than trying to count them all afterwards and you do have the physical evidence of neutrons to check after the experiment.
Jon Rosenstiel
Posts: 1494
Joined: Thu Jun 28, 2001 1:30 am
Real name: Jon Rosenstiel
Location: Southern California

Re: FAQ - Bubble Fast Neutron Detector

Post by Jon Rosenstiel »

Received an early Christmas present today, via FedEx. The BD-100R arrived packed in an oversized box containing bubble wrap (appropriate) and Styrofoam peanuts. Eight days from order placement to holding the detector in my hot little hands. Not so bad, I’d say.

The double ouch was the import/shipping cost, $100.00!

Evidently, one must ask for the temperature response curve when ordering, as none came with it. I’ll have to fire off an e-mail next week requesting the curve.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
UPDATED 12/18/04.....
After posting this (late Friday evening) I sent an email to BTI. The temp response curve was in my inbox this morning (Saturday), with apology.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

With any luck I’ll be able to give it a test run this weekend. I’ll post my findings here.

Based on Richard Hull’s experience with his bubble detector, I expect that my neutron numbers will be nowhere near as high as my Ludlum (just recently re-calibrated) rem ball says they are. I’m preparing myself for a 65% drop in total isotropic emission rate. I’m afraid the truth is gonna’ hurt!

Stay tuned….
Jon Rosenstiel
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