A theoretical discussion based on data re. fusor conditioning fusion
Posted: Mon Oct 01, 2018 12:16 am
This is my very first posting in this "most serious of forums". While this is a long posting, I have put a lot of thought into it based on real experience and data collected over the years. Bacon's essay on studies is brought to mind... "Read not to believe and take for granted, but to weigh and consider". Those here capable of weighing and considering based on science will appreciate this effort, I believe.
I have noted and put up data on this subject several times in these forums. I have been "conditioning" fusor IV for the HEAS event. I supply a table below of the last 4 day run sessions. This kind of data is representative of every time I have started up my fusor after a moribund period of use. I feel that I am the only one to report on this, perhaps, "my phenomenon". Is it peculiar to fusor IV or the manner in which I operate this system?? Would others see this if operating the way I do? I struggle for about 5 days to condition my fusor after one-half to one full year idle time between one million neutron per second runs. Such runs are not for my pleasure, as a rule. They are for special events or to work on activation experiments which are few and far between. I will use actual experimental observations and data collected over many years of real fusor operations that force me to attempt to explain this "conditioning", as I have dubbed it, in this forum.
In general, I make the following observations from the work of myself and others
1. Few successful fusioneers here ever operate their fusors over a period of years. Most are just "hit-and-run" people, not true amateur fusioneers.
2. The few who do run their fusors over years, rarely report on idle time periods or start up issues.
3. My system always has had a very slow leak, but a leak to the point that if the chamber is left under its last run vacuum for more than a week it is effectively at atmosphere. However, there is not much water vapor to burn off as the fusor pulls to a mechanical vacuum of ~10 microns in a minute or two even after long periods of non-use.
4. First runs after long moribund periods result in only a further reduction of ~2-3 microns with rather significant glow cleaning as the chamber gets quite hot.
5. The bottom for me, with my diff pump running, is on the order of 10e-4 torr.
6. Continuous, day to day running of the fusor never changes this bottoming value. (water and crud all gone)
7. if I run the fusor for 3-4 hours in conditioning tests or in mega mark runs,(re-iterating #5 & #6), as I bring the system down, I first cut the D2 gas flow, leaving the mechanical and hot diff pump running, I now open the chamber to diff pump valve back to wide open and the Baratron gauge dives from the fusion D2 pressure down to 10e-4 torr, the normal bottoming pressure. For years I though it was all about a dirty, unused fusor needing to be cleaned out over time. I no longer accept this hypothesis!
Here is the table
Day 1 Best run 39kv @ 10ma 4.5 microns 22,900 n/s iso
day 2 Best run 38kv @16ma 5.7 microns 42,000 n/s iso
Day 3 Best run 39.7kv @ 6.8 microns 94,800 n/s iso
day 4 Best run 40kv @ 11ma 9 microns 378,100 n/s iso
day 5 Best Run 40kv @ 11ma 9.6 microns 490,100 n/s iso
day 6 Best run 39kv @ 11.6ma 11.7 microns 627,200 n/s iso
Experimental observations
It is plainly obvious that mere voltage in not playing any real part in the fusion over 6 days. Current also has little effect over the period, either. Pressure is key! It was physically impossible to get 9 microns to function on day one after the fusor has not been run for 4 months (June 2018). Trying to introduce 9 microns of deuterium gas on day one would force huge currents at useful fusion voltages that would force electron-runaway. This would increase ionization currents at much lower, non-fusing voltages and melt the grid. It may turn out that pressure is not all that significant beyond increasing the deuterium lattice wall loading maintenance and increasing this loading.
Theoretical machinations
I feel that the higher pressures are possible due to buried deuterium in the SS shell or wall surface lattice by fast neutrals. Why??
1. In the early stages of operation, all water is gone and all things being equal, the leak in my system is uniform and doesn't figure in over time at all.
2. In the beginning, (day one), fusion is due solely to random ionization of the gas increasing voltages and currents work to get advantageous fusions over the entire volume of gas. As the current goes up to increase the ion content so the electron current goes up and the grid heats such that more gas can't be put into the system without reducing fusion and increasing current. This, if continued, will melt the grid.
3. The higher pressure capability increases as the buried deuterium is freed up at the shell walls and is ionized at the wall by the current of very energetic electrons racing for the shell.
4. This "close-shell" ionization puts a huge number of deuterons capable of making it to the grid or the outer grid volume "AT FUSION ENERGY".
5. The ideal is to make deuterons at the shell walls so that the deuterons created there will have the full acceleratory energy of the potential difference between the wall and the grid.
6. Increased flowing gas pressures are possible to feed the wall loaded as fusion increases due to wall based ionization. The increased pressure allows both the random inter grid ionizations seen on day one to join the new wall based ionizations at the same currents and voltages to do a much better job of utilizing both the voltage probabilities and the current driven ionization numbers.
7. Wall ionization currents pour more energy into the deuteron and less into the electron. The electron hits the shell in a tiny acceleratory path while the deuteron gets to accelerate over the entire distance to the grid, (ideally).
8. Meanwhile the near valueless day one events continue to blast electrons into the shell to free more deuterons, now packed into the lattice and the bulk of the inter-volume deuterons fail to fuse, (as on day one), become neutrals and bury into the walls.
9. The above cyclic action continues day after day and often, as seen here, on the 6th or 7th day of operation, I am attaining 1.5million neuts per second isotropic at 39kv and 13ma current and 16 microns of pressure.
My take on conditioning
At first, you can't get a lot of voltage before before getting the fuel pressure up. The high currents with little fusion at reduced voltages does two things. 1. Not much fusion, even though a minimal amount does take place. This is strictly due to "Volume Ionization" where deuterons are created all over the volume of the chamber. The vast majority of deuterons never do fusion as a lot of energy goes to the electrons that blast the shell, while the deuterons tend to wind up as fast neutrals, also bombarding the shell. 2. The profusion of neutrals slowly insinuate themselves into the walls of the fusor such that the fierce electron bombardment pops a few deuterons back out and makes what little fusion happens through a full acceleratory trajectory. This wall loading action continues throughout any given fusor operational session.
In subsequent daily operations this loading continues and more of the current, (energy), supplied goes to doing fusion via wall ionized deuteron release. This reduces electron energies but not so much that they still can't hit the wall and ionize the deuterium. This action allows more fuel to be admitted and more wall loading to take place. The volume ionization still takes place, but this continues to load the wall and creates both fast neutrals and a few fast deuterons. These fast deuterons can do fusion with the ultra high speed shell produced deuterons.
In continued later daily operational scenarios, more fuel can be added and the same current at any given voltage will do more fusion as the process snowballs with more weak electrons and hyper fast wall based deuterons continue all the above previous processes, but on steroids.
Remember all metals, 100% of them, have surface lattices and all absorb hydrogen to a greater or lesser degree. Those of a lesser degree tend to lose their grip on the hydrogen insinuated within them with more ease. (less energy is needed to release the hydrogen than that of a hydrogen hungry metal). Stainless steel is an alloy. It is probably not a great hydrogen absorber and is likely not inclined to hold on to its hydrogen under high energy particle, (electron), bombardment.
Summary
It is all about pressure in operation of the fusor. Pressure increases become more and more possible with wall buried deuterium doing the fusion. Near wall ionization, (deuteron creation), does almost all fusion of significance in a simple fusor. All fusion still takes place over the entire volume of the device. The volumetric fusion is simply enhanced by wall produced deuterons. Those electrons are not a complete waste once the large surface area wall is loaded. The true beauty of the spherical fusor is revealed...A giant surface area loaded with deuterium under constant bombardment of ionizing electrons, while at the same time absorbing both fast and slow neutrals reloading the walls.
edit: new data
Over the last few days, I have noticed something I have seen many times before, but just pushed it aside. (bad form indeed).
In the early "unloaded stages" day1 and day two. I set the D2 gas flow at the lower micron levels and can't seem to get this flow to move up. (important)...I do know that in these early days that the rigidly set gas flow tends to drop only a micron of two as I fiercely try to get the voltage up and the resultant current causes the grid to glow orange hot to almost white hot producing terrible fusion for all the voltage and current poured into the gas. On day 6, as the "walls are loaded" or conditioned, as I posit, I set the gas pressure a little higher than the day before on the first run by maybe one micron. This pressure is dead stable, of course.
I slam the power to the fusor and find that now I do fantastic fusion on the first run on day 6, the voltage rises and the current drops dramatically!! What!! I look at the baratron pressure reading an my 10 micron setting is now at 7.3 microns!! I run the voltage back up, the current goes up and more fusion takes place, the counter is going nuts! Again, the voltage starts going up and the current slips below 8 ma and the pressure is now 6.5 microns. Again...What! I am quickly approaching fusor IVs "rope limit". 42kv. I kill the power and the pressure rises to near my original setting.
I, now, over compensate and open the gas valve to a stable 15 microns figuring it will drop again. It does, indeed, drop to 10 microns as I approach the "42kv rope limit". This is all done in barely enough time to do a 2 minute timed count run as the voltage is rising and the current dropping. The fusion is doing fabulously more as I now have 10 microns at the limit instead of 7.3 or 6.5 as in the last run before upping the pressure for this run.
Any "real fusioneer" out there who has operated their fusor for hours after a huge dead period notice this above effect?
If not a foible peculiar to my fusor, could I be loading and unloading the walls at a rate that sucks up a fraction of my initial pressure??
Richard Hull
I have noted and put up data on this subject several times in these forums. I have been "conditioning" fusor IV for the HEAS event. I supply a table below of the last 4 day run sessions. This kind of data is representative of every time I have started up my fusor after a moribund period of use. I feel that I am the only one to report on this, perhaps, "my phenomenon". Is it peculiar to fusor IV or the manner in which I operate this system?? Would others see this if operating the way I do? I struggle for about 5 days to condition my fusor after one-half to one full year idle time between one million neutron per second runs. Such runs are not for my pleasure, as a rule. They are for special events or to work on activation experiments which are few and far between. I will use actual experimental observations and data collected over many years of real fusor operations that force me to attempt to explain this "conditioning", as I have dubbed it, in this forum.
In general, I make the following observations from the work of myself and others
1. Few successful fusioneers here ever operate their fusors over a period of years. Most are just "hit-and-run" people, not true amateur fusioneers.
2. The few who do run their fusors over years, rarely report on idle time periods or start up issues.
3. My system always has had a very slow leak, but a leak to the point that if the chamber is left under its last run vacuum for more than a week it is effectively at atmosphere. However, there is not much water vapor to burn off as the fusor pulls to a mechanical vacuum of ~10 microns in a minute or two even after long periods of non-use.
4. First runs after long moribund periods result in only a further reduction of ~2-3 microns with rather significant glow cleaning as the chamber gets quite hot.
5. The bottom for me, with my diff pump running, is on the order of 10e-4 torr.
6. Continuous, day to day running of the fusor never changes this bottoming value. (water and crud all gone)
7. if I run the fusor for 3-4 hours in conditioning tests or in mega mark runs,(re-iterating #5 & #6), as I bring the system down, I first cut the D2 gas flow, leaving the mechanical and hot diff pump running, I now open the chamber to diff pump valve back to wide open and the Baratron gauge dives from the fusion D2 pressure down to 10e-4 torr, the normal bottoming pressure. For years I though it was all about a dirty, unused fusor needing to be cleaned out over time. I no longer accept this hypothesis!
Here is the table
Day 1 Best run 39kv @ 10ma 4.5 microns 22,900 n/s iso
day 2 Best run 38kv @16ma 5.7 microns 42,000 n/s iso
Day 3 Best run 39.7kv @ 6.8 microns 94,800 n/s iso
day 4 Best run 40kv @ 11ma 9 microns 378,100 n/s iso
day 5 Best Run 40kv @ 11ma 9.6 microns 490,100 n/s iso
day 6 Best run 39kv @ 11.6ma 11.7 microns 627,200 n/s iso
Experimental observations
It is plainly obvious that mere voltage in not playing any real part in the fusion over 6 days. Current also has little effect over the period, either. Pressure is key! It was physically impossible to get 9 microns to function on day one after the fusor has not been run for 4 months (June 2018). Trying to introduce 9 microns of deuterium gas on day one would force huge currents at useful fusion voltages that would force electron-runaway. This would increase ionization currents at much lower, non-fusing voltages and melt the grid. It may turn out that pressure is not all that significant beyond increasing the deuterium lattice wall loading maintenance and increasing this loading.
Theoretical machinations
I feel that the higher pressures are possible due to buried deuterium in the SS shell or wall surface lattice by fast neutrals. Why??
1. In the early stages of operation, all water is gone and all things being equal, the leak in my system is uniform and doesn't figure in over time at all.
2. In the beginning, (day one), fusion is due solely to random ionization of the gas increasing voltages and currents work to get advantageous fusions over the entire volume of gas. As the current goes up to increase the ion content so the electron current goes up and the grid heats such that more gas can't be put into the system without reducing fusion and increasing current. This, if continued, will melt the grid.
3. The higher pressure capability increases as the buried deuterium is freed up at the shell walls and is ionized at the wall by the current of very energetic electrons racing for the shell.
4. This "close-shell" ionization puts a huge number of deuterons capable of making it to the grid or the outer grid volume "AT FUSION ENERGY".
5. The ideal is to make deuterons at the shell walls so that the deuterons created there will have the full acceleratory energy of the potential difference between the wall and the grid.
6. Increased flowing gas pressures are possible to feed the wall loaded as fusion increases due to wall based ionization. The increased pressure allows both the random inter grid ionizations seen on day one to join the new wall based ionizations at the same currents and voltages to do a much better job of utilizing both the voltage probabilities and the current driven ionization numbers.
7. Wall ionization currents pour more energy into the deuteron and less into the electron. The electron hits the shell in a tiny acceleratory path while the deuteron gets to accelerate over the entire distance to the grid, (ideally).
8. Meanwhile the near valueless day one events continue to blast electrons into the shell to free more deuterons, now packed into the lattice and the bulk of the inter-volume deuterons fail to fuse, (as on day one), become neutrals and bury into the walls.
9. The above cyclic action continues day after day and often, as seen here, on the 6th or 7th day of operation, I am attaining 1.5million neuts per second isotropic at 39kv and 13ma current and 16 microns of pressure.
My take on conditioning
At first, you can't get a lot of voltage before before getting the fuel pressure up. The high currents with little fusion at reduced voltages does two things. 1. Not much fusion, even though a minimal amount does take place. This is strictly due to "Volume Ionization" where deuterons are created all over the volume of the chamber. The vast majority of deuterons never do fusion as a lot of energy goes to the electrons that blast the shell, while the deuterons tend to wind up as fast neutrals, also bombarding the shell. 2. The profusion of neutrals slowly insinuate themselves into the walls of the fusor such that the fierce electron bombardment pops a few deuterons back out and makes what little fusion happens through a full acceleratory trajectory. This wall loading action continues throughout any given fusor operational session.
In subsequent daily operations this loading continues and more of the current, (energy), supplied goes to doing fusion via wall ionized deuteron release. This reduces electron energies but not so much that they still can't hit the wall and ionize the deuterium. This action allows more fuel to be admitted and more wall loading to take place. The volume ionization still takes place, but this continues to load the wall and creates both fast neutrals and a few fast deuterons. These fast deuterons can do fusion with the ultra high speed shell produced deuterons.
In continued later daily operational scenarios, more fuel can be added and the same current at any given voltage will do more fusion as the process snowballs with more weak electrons and hyper fast wall based deuterons continue all the above previous processes, but on steroids.
Remember all metals, 100% of them, have surface lattices and all absorb hydrogen to a greater or lesser degree. Those of a lesser degree tend to lose their grip on the hydrogen insinuated within them with more ease. (less energy is needed to release the hydrogen than that of a hydrogen hungry metal). Stainless steel is an alloy. It is probably not a great hydrogen absorber and is likely not inclined to hold on to its hydrogen under high energy particle, (electron), bombardment.
Summary
It is all about pressure in operation of the fusor. Pressure increases become more and more possible with wall buried deuterium doing the fusion. Near wall ionization, (deuteron creation), does almost all fusion of significance in a simple fusor. All fusion still takes place over the entire volume of the device. The volumetric fusion is simply enhanced by wall produced deuterons. Those electrons are not a complete waste once the large surface area wall is loaded. The true beauty of the spherical fusor is revealed...A giant surface area loaded with deuterium under constant bombardment of ionizing electrons, while at the same time absorbing both fast and slow neutrals reloading the walls.
edit: new data
Over the last few days, I have noticed something I have seen many times before, but just pushed it aside. (bad form indeed).
In the early "unloaded stages" day1 and day two. I set the D2 gas flow at the lower micron levels and can't seem to get this flow to move up. (important)...I do know that in these early days that the rigidly set gas flow tends to drop only a micron of two as I fiercely try to get the voltage up and the resultant current causes the grid to glow orange hot to almost white hot producing terrible fusion for all the voltage and current poured into the gas. On day 6, as the "walls are loaded" or conditioned, as I posit, I set the gas pressure a little higher than the day before on the first run by maybe one micron. This pressure is dead stable, of course.
I slam the power to the fusor and find that now I do fantastic fusion on the first run on day 6, the voltage rises and the current drops dramatically!! What!! I look at the baratron pressure reading an my 10 micron setting is now at 7.3 microns!! I run the voltage back up, the current goes up and more fusion takes place, the counter is going nuts! Again, the voltage starts going up and the current slips below 8 ma and the pressure is now 6.5 microns. Again...What! I am quickly approaching fusor IVs "rope limit". 42kv. I kill the power and the pressure rises to near my original setting.
I, now, over compensate and open the gas valve to a stable 15 microns figuring it will drop again. It does, indeed, drop to 10 microns as I approach the "42kv rope limit". This is all done in barely enough time to do a 2 minute timed count run as the voltage is rising and the current dropping. The fusion is doing fabulously more as I now have 10 microns at the limit instead of 7.3 or 6.5 as in the last run before upping the pressure for this run.
Any "real fusioneer" out there who has operated their fusor for hours after a huge dead period notice this above effect?
If not a foible peculiar to my fusor, could I be loading and unloading the walls at a rate that sucks up a fraction of my initial pressure??
Richard Hull