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Post by RiftandRend on Jun 8, 2017 12:19:05 GMT
Ahh, I didn't know about that multiplier. The business with the pions and gammas made me question the accuracy of the reaction. Ill still probably use positrons though, they are easier to define reactions for (they don't hit hardcoded limits). One problem I hit was that calculating the amount fusion reactions a specific amount of antimatter can initiate isn't correct, after a certain amount of antimatter the fusion can "sustain" itself. Documents and my calculations hit around 1µg to initiate a fusion reaction. Thermonuclear weapons need a fissile bomb to initiate the their second fusion stage, but after than you can add infinitely more fusion stages. If one microgram can initiate any fusion reaction that will make this way easier to calculate.
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Post by Kerr on Jun 8, 2017 12:23:47 GMT
One problem I hit was that calculating the amount fusion reactions a specific amount of antimatter can initiate isn't correct, after a certain amount of antimatter the fusion can "sustain" itself. Documents and my calculations hit around 1µg to initiate a fusion reaction. Thermonuclear weapons need a fissile bomb to initiate the their second fusion stage, but after than you can add infinitely more fusion stages. If one microgram can initiate any fusion reaction that will make this way easier to calculate. Yup, you need a balance, AM to fusion catalyzed fusion, on paper 1 antiproton can create a infinitely many fusion reactions, using 300kev D-He³ fusion one antiproton generates 76.1GeV of energy, and these 76,1 GeV can initiate more fusions, and so on. But only if all energy is perfectly absorbed by other fusion fuel, which is, nearly impossible.
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Post by RiftandRend on Jun 8, 2017 12:44:03 GMT
I have come up with a scheme to create 3He. Use particle accelerators to create unstable isotopes. Those isotopes emit neutrons that convert deuterium into tritium. This tritium decays into 3He. This process is probably very, very inefficient but should be preferable to antimatter manufacture.
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Post by The Astronomer on Jun 8, 2017 12:47:22 GMT
I have come up with a scheme to create 3He. Use particle accelerators to create unstable isotopes. Those isotopes emit neutrons that convert deuterium into tritium. This tritium decays into 3He. This process is probably very, very inefficient but should be preferable to antimatter manufacture. Tritium decays into He-3? Awesome, we don't have to mine gas giants now. Just activate deuterium
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Post by Kerr on Jun 8, 2017 12:50:37 GMT
I have come up with a scheme to create 3He. Use particle accelerators to create unstable isotopes. Those isotopes emit neutrons that convert deuterium into tritium. This tritium decays into 3He. This process is probably very, very inefficient but should be preferable to antimatter manufacture. Ok, that sounds overly complicated, why don't you produce helium-3 in the first place if you use particle accelerators to generate isotopes. Also I calculated some ratios for fusion: 13TJ/1 KeV D-T Fusion 11TJ/1 KeV D-He³ Fusion 0,35TJ/1 KeV p+B11 For Engine Size: 1TW DT Fusion needs a 120m radius for 3000K. 1TW D-He³ Fusion needs 66m radius, this is because at the D-He³ peak efficiency the reaction produces a lot of x-rays. To minimize them you need to fuse them at 100KeV, limiting the exhaust velocity to 7.8Mm/s.
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Post by Kerr on Jun 8, 2017 12:59:31 GMT
I have come up with a scheme to create 3He. Use particle accelerators to create unstable isotopes. Those isotopes emit neutrons that convert deuterium into tritium. This tritium decays into 3He. This process is probably very, very inefficient but should be preferable to antimatter manufacture. Tritium decays into He-3? Awesome, we don't have to mine gas giants now. Just activate deuterium Still wondering, if we can produce isotopes which activate deuterium to tritium which decays into helium-3 with particle accelerators, why don't we use the particle acceleratprs to produce helium-3 in the first place? bombard deuterium with protons.
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Post by RiftandRend on Jun 8, 2017 13:00:33 GMT
I have come up with a scheme to create 3He. Use particle accelerators to create unstable isotopes. Those isotopes emit neutrons that convert deuterium into tritium. This tritium decays into 3He. This process is probably very, very inefficient but should be preferable to antimatter manufacture. Ok, that sounds overly complicated, why don't you produce helium-3 in the first place if you use particle accelerators to generate isotopes. Also I calculated some ratios for fusion: 13TJ/1 KeV D-T Fusion 11TJ/1 KeV D-He³ Fusion 0,35TJ/1 KeV p+B11 For Engine Size: 1TW DT Fusion needs a 120m radius for 3000K. 1TW D-He³ Fusion needs 66m radius, this is because at the D-He³ peak efficiency the reaction produces a lot of x-rays. To minimize them you need to fuse them at 100KeV, limiting the exhaust velocity to 7.8Mm/s. I don't know how to factor in fusing efficiency using the current crude implementation. I guess I could just lower the fuel energy.
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Post by The Astronomer on Jun 8, 2017 13:01:29 GMT
Tritium decays into He-3? Awesome, we don't have to mine gas giants now. Just activate deuterium Still wondering, if we can produce isotopes which activate deuterium to tritium which decays into helium-3 with particle accelerators, why don't we use the particle acceleratprs to produce helium-3 in the first place? bombard deuterium with protons. The future is bright! I think that's perfectly plausible in 100 years' time.
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Post by RiftandRend on Jun 8, 2017 13:02:14 GMT
Tritium decays into He-3? Awesome, we don't have to mine gas giants now. Just activate deuterium Still wondering, if we can produce isotopes which activate deuterium to tritium which decays into helium-3 with particle accelerators, why don't we use the particle accelerators to produce helium-3 in the first place? bombard deuterium with protons. Is that even possible? That's basically deuterium-proton fusion.
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Post by Kerr on Jun 8, 2017 13:05:19 GMT
Still wondering, if we can produce isotopes which activate deuterium to tritium which decays into helium-3 with particle accelerators, why don't we use the particle accelerators to produce helium-3 in the first place? bombard deuterium with protons. Is that even possible? That's basically deuterium-proton fusion. Why would creating isotopes be possible and creating helium-3 not? Particle accelerators can produce any isotope and element. Ununoctium was can and is only produced this way.
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Post by Kerr on Jun 8, 2017 13:13:18 GMT
Ok, that sounds overly complicated, why don't you produce helium-3 in the first place if you use particle accelerators to generate isotopes. Also I calculated some ratios for fusion: 13TJ/1 KeV D-T Fusion 11TJ/1 KeV D-He³ Fusion 0,35TJ/1 KeV p+B11 For Engine Size: 1TW DT Fusion needs a 120m radius for 3000K. 1TW D-He³ Fusion needs 66m radius, this is because at the D-He³ peak efficiency the reaction produces a lot of x-rays. To minimize them you need to fuse them at 100KeV, limiting the exhaust velocity to 7.8Mm/s. I don't know how to factor in fusing efficiency using the current crude implementation. I guess I could just lower the fuel energy. Find out the percentage of radiation each reaction releases, hot D-He³ 20%, D-T 80%, p+B11 0%. The distance increases/decreases with the square root of the energy increase, a 500GW engine needs only 60m for D-T/ 33m for D-He³.
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Post by Kerr on Jun 8, 2017 13:29:16 GMT
I don't know how to factor in fusing efficiency using the current crude implementation. I guess I could just lower the fuel energy. Find out the percentage of radiation each reaction releases, hot D-He³ 20%, D-T 80%, p+B11 0%. The distance increases/decreases with the square root of the energy increase, a 500GW engine needs only 60m for D-T/ 33m for D-He³. Sounds like an inherent advantage of p+B11 fusion rockets, they can use their full potential of 13,5Mm/s. Without to big of an engine, an 1MN 20.1Mm/s need a 600m diameter engine to not get damaged. Considering that x-ray aren't higher at these energies than on the examples, which they most likely are.
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Post by RiftandRend on Jun 8, 2017 13:31:13 GMT
I don't know how to factor in fusing efficiency using the current crude implementation. I guess I could just lower the fuel energy. Find out the percentage of radiation each reaction releases, hot D-He³ 20%, D-T 80%, p+B11 0%. The distance increases/decreases with the square root of the energy increase, a 500GW engine needs only 60m for D-T/ 33m for D-He³. I don't really get it, where do these distances come from? And by radiation are you referring to fast neutrons? Is something like this feasible?
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Post by The Astronomer on Jun 8, 2017 13:35:29 GMT
I talked with a guy on Isaac Arthur's facebook group, and he suggested the polywell instead of antimatter catalyst.
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Post by Kerr on Jun 8, 2017 13:40:47 GMT
Find out the percentage of radiation each reaction releases, hot D-He³ 20%, D-T 80%, p+B11 0%. The distance increases/decreases with the square root of the energy increase, a 500GW engine needs only 60m for D-T/ 33m for D-He³. I don't really get it, where do these distances come from? And by radiation are you referring to fast neutrons? Is something like this feasible? Inverse square law, for a 1TW D-T rocket use 800GW and the inverse square law, after some distance you get below 4,5 MW per square meters. I don't know how many x-ray it produces at the temperature of 100 kev, only that it is the temperature with the lowest amount of x-ray. It should survive, but now try to build a p+B11, you can achieve higher exhaust velocities.
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