3 ms·

Having built much of a fusion reactor in my apartment... (but not the classic Farnsworth design) 1) A much easier (and usually cheaper and more accurate) way t

Having built much of a fusion reactor in my apartment... (but not the classic Farnsworth design) 1) A much easier (and usually cheaper and more accurate) way to measure neutrons is to just rent a proper device, from somewhere like: https://instruments.energysolutions.com/instrument-rental/neutron-meters/ https://instruments.energysolutions.com/instrument-rental/ne.... Not a big fan of bubble dosimeters, except when you need to measure a place you cannot be at the time of measurement (like on the unshielded roof of a linac bunker). 2) Best to check with your significant other before doing stuff in shared areas. Twice I have been banned from "doing science stuff in the kitchen", once when I got a 5" NeFeB magnet stuck to the oven and we almost got badly injured removing it, and once when I thermally decomposed AlOH3 in the oven. This is why the rest of the fusion reactor was not built at home. 3) Power supplies are an important and expensive component. We got most of ours by buying an obsolete ion implanter, and just pulled the power supplies from it. This is a lot cheaper than buying new or even used stand-alone supplies. However, the problem with old power supplies is sometimes they have a problem, and troubleshooting high voltage supplies can be more than tricky. A 180 kV supply got me bad once when the drain resistor was broken and I tried to change a capacitor - when I felt the zap go in one hand and out where I was sitting, I thought "ok, I'm dead". Luckily it wasn't enough charge to kill me. Invest in a long dry wooden dowel, so you can check if surfaces are charged before you touch them.

ohiovr 4y ago
Could you comment on something I was thinking about casually one day. I reckon the grid causes ions to slam into it and lose energy. Why not intentionally cause cathode "grid" be part of the fuel? For instance think of a specially designed water cutting jet that shot a very thin beam of heavy water in the center of a cavity that was disc shaped. The Anode is around the perimeter. The body is made of fused silica welded with fluxed glass. The heavy water could have a little lithium in it to make it very electrically conductive. The water is at earth ground. The ions get accelerated to the beam and hit it dead on along with the heavy water deuterium inside of it. They may also meet particles coming in from the opposite direction. What do you think of the idea?
- FiatLuxDave 4y ago
  Sure, no prob. What you describe is very similar to the design of a https://en.wikipedia.org/wiki/Neutron_generator https://en.wikipedia.org/wiki/Neutron_generator , except replacing the deuteron-metal hydride with a stream of heavy water. There might be some small advantages to using oxygen as the matrix holding the deuterium instead of metal (lower Z-number means more energy goes into ion collision as opposed to heating electrons). But even if you were to have a pure deuterium target, this type of design has the problem that when your target is colder than your ions, the target gets heated up. This either turns it to a plasma (which then starts to radiate away energy and needs containment) or if you cool it to keep it cold, the colder the electrons in the material are the faster they absorb energy from the ions, and so most of your ion energy goes towards heating electrons rather than initiating fusion collisions. So, yeah, it would work to make fusion reactions, but I don't know if it would be worth the added complexity over just using a hydride electrode. Titanium is basically a deuterium sponge.
  - ohiovr 4y ago
    Thank you so much for your feedback!
  - ohiovr 4y ago
    Would you like to entertain another thought I had?
    - FiatLuxDave 4y ago
      Sure, hit me
      - ohiovr 4y ago
        Ions in a magnetic field swirl in one direction while electrons swirl in the other. Metals when they are being dragged across a magnetic field form eddy currents that oppose the direction of travel of the magnet. In a wire a magnet traversing it makes one end positively charged and the other end negatively charged. In this respect, like charges seem to be concentrating when under the influence of the magnet. Is it right to assume the current is larger with thicker wire and more powerful magnets and the voltage depends on the relative speed of the magnet? A very short piece of wire encased in CVD diamond and further encased in borosilicate glass. The cavity is filled with fuel gas, the wire is also fuel. A powerful enough magnet, traveling at a fast enough rate could tear the metal down electrically separate its electric charges and when they gyrate they are blocked by the cavity. Diamond is the most atomically dense material with the highest breakdown voltage and also offers very good hydrophobic resistance. Perhaps if we could get the ions in one corner with enough electric pressure they would react.CVD diamond can offer a high degree of precision, and perfect seeds could be further grown imperfectly using high pressure solvent methods into larger, rougher, and tougher forms. A train car (for comedy relief I added a train) with a superconducting magnet on the side of it as it travels induces the magnetic field to concentrate the charges. The charges get bunched up in the corner of a diamond crystal, they have a little heat too, and wham-o, they fuse. Or just crack the glass. But diamond can keep back tremendous pressure. I haven't seen what kind of pressures are possible to obtain by using diamond cavities instead of extremities.

ohiovr 4y ago

Could you comment on something I was thinking about casually one day. I reckon the grid causes ions to slam into it and lose energy. Why not intentionally cause cathode "grid" be part of the fuel? For instance think of a specially designed water cutting jet that shot a very thin beam of heavy water in the center of a cavity that was disc shaped. The Anode is around the perimeter. The body is made of fused silica welded with fluxed glass. The heavy water could have a little lithium in it to make it very electrically conductive. The water is at earth ground. The ions get accelerated to the beam and hit it dead on along with the heavy water deuterium inside of it. They may also meet particles coming in from the opposite direction. What do you think of the idea?

FiatLuxDave 4y ago
Sure, no prob. What you describe is very similar to the design of a https://en.wikipedia.org/wiki/Neutron_generator https://en.wikipedia.org/wiki/Neutron_generator , except replacing the deuteron-metal hydride with a stream of heavy water. There might be some small advantages to using oxygen as the matrix holding the deuterium instead of metal (lower Z-number means more energy goes into ion collision as opposed to heating electrons). But even if you were to have a pure deuterium target, this type of design has the problem that when your target is colder than your ions, the target gets heated up. This either turns it to a plasma (which then starts to radiate away energy and needs containment) or if you cool it to keep it cold, the colder the electrons in the material are the faster they absorb energy from the ions, and so most of your ion energy goes towards heating electrons rather than initiating fusion collisions. So, yeah, it would work to make fusion reactions, but I don't know if it would be worth the added complexity over just using a hydride electrode. Titanium is basically a deuterium sponge.
- ohiovr 4y ago
  Thank you so much for your feedback!
- ohiovr 4y ago
  Would you like to entertain another thought I had?
  - FiatLuxDave 4y ago
    Sure, hit me
    - ohiovr 4y ago
      Ions in a magnetic field swirl in one direction while electrons swirl in the other. Metals when they are being dragged across a magnetic field form eddy currents that oppose the direction of travel of the magnet. In a wire a magnet traversing it makes one end positively charged and the other end negatively charged. In this respect, like charges seem to be concentrating when under the influence of the magnet. Is it right to assume the current is larger with thicker wire and more powerful magnets and the voltage depends on the relative speed of the magnet? A very short piece of wire encased in CVD diamond and further encased in borosilicate glass. The cavity is filled with fuel gas, the wire is also fuel. A powerful enough magnet, traveling at a fast enough rate could tear the metal down electrically separate its electric charges and when they gyrate they are blocked by the cavity. Diamond is the most atomically dense material with the highest breakdown voltage and also offers very good hydrophobic resistance. Perhaps if we could get the ions in one corner with enough electric pressure they would react.CVD diamond can offer a high degree of precision, and perfect seeds could be further grown imperfectly using high pressure solvent methods into larger, rougher, and tougher forms. A train car (for comedy relief I added a train) with a superconducting magnet on the side of it as it travels induces the magnetic field to concentrate the charges. The charges get bunched up in the corner of a diamond crystal, they have a little heat too, and wham-o, they fuse. Or just crack the glass. But diamond can keep back tremendous pressure. I haven't seen what kind of pressures are possible to obtain by using diamond cavities instead of extremities.