Questions regarding the Boron market

Discuss how polywell fusion works; share theoretical questions and answers.

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SymenJ
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Questions regarding the Boron market

Postby SymenJ » Sun May 31, 2015 5:32 pm

Dear all,

Earlier this year I posted a topic regarding a research I am doing on the Polywell technique. Now my professor asked me to get an overview on the boron market. This information can be used to further create awareness on the possibilities of the technique. I already send several questions to players in the market. Some of the questions are down below. As you maybe can make up I am a real rookie on this technique (undergraduate student only) Any help would be greatly appreciated!

1. Which of the natural resources is used the most to acquire boron?

2. Which different methods are used to acquire the minerals?

3. Can you give an overview of the global supplies?

4. Which different processes are used to process the minerals?

5. Which processes are used to separate the isotopes B-10 and B-11?

6. In which different forms is boron available on the market? I.e. different compounds? Different allotropes? Aggregation forms? Purification level?

7. What process is used to achieve a high boron purification?

8. Are there any special requirements for the storage of boron?

9. How does the process look like for the product to end up at the user?

Regulation and pricing:
1. Are there any regulations involved in acquiring and storing boron?

2. Are there any regulations involved in acquiring and storing boron?

3. What are the prices for different boron compounds?


Furthermore we are interested in the ionization of the boron isotope (i.e. by ionization guns). How exactly is the boron isotope ionized and brought into the reactor (i.e. gas phase)? What percentage of purity is necessary for an efficient reactor? Any implications the gaseous boron has on the reactor?


Thanks in advance!

D Tibbets
Posts: 2769
Joined: Thu Jun 26, 2008 6:52 am

Re: Questions regarding the Boron market

Postby D Tibbets » Sun May 31, 2015 7:16 pm

Boron in mined for multiple uses, and isotopic separation of B10 and B11 is already industrially aviable for the nuclear industry and for radiation resistant electronics. Look up boron and decaborane Wikapedia articles. Some may criticize Wikipedia as not consistent as a qualitysource of information but the articles are useful as introduction and do have bibliographies at the end.

Boron mining is not limited to only deposits in mines, though these are the most economical- and thus exploited. Sea water contains a huge amount and can be extracted once the costs are tolerable for the application. As such available boron for fusion is much greater than other industrial uses because tiny amounts produce a large amount of fusion energy. The cost of the boron11 fuel, even after inflated acquisition costs and isotopic purification costs, make up only a tiny fraction of the system cost for a presumed workable P-B11 fusion reactor. My guess is that the cost for the B11 is much less than the cost of Uranium 235 per KWH.

Decaboranes have been mentioned as a feed material for a fusion reactor. There are versions that are a gas at room temperature. Note that for Bremsstruhlung radiation control purposes a reactor will probably be configured with excess hydrogen (protons) so the proportionate greater hydrogen atom numbers in the decaborane is not a problem. Additional hydrogen gas will probably be needed in addition to this. A ratio of 10 protons per one Boron11 has been mentioned by Bussard as a likely mix. Bremsstruhung radiation scales with the square of the Z or atomic number of the ion. At Z of 5 for boron, the Bremsstruhlung radiation is ~25 times greater than for a proton. By having excess protons, the fusion rate, as determined by the density of reacting particles, is not harmed much , but the net Bremsstruhlung radiation losses are reduced significantly. Note also, that the Bremsstruhlung radiation in a Polywell may be reduced by the dynamic distribution of the electron energy/ speed within the system. This is due to the potential well and effects on the electron and ion speed in a (hopefully) centrally convergent quasi-spherical reaction volume. Electrons are slow in the center where the ion concentration is greatest. These two considerations are the arguments for Polywell P-B11 fusion profitability despite Riders concerns about the limiting losses due to Bremsstruhlung.

The degree of ionization of the boron is probably 100% for most of the boron. At hundreds of KeV there will be few neutral or partially ionized borons within the reaction volume- inside the Wiffleball. Another consideration is that only ions and electrons are contained within the wiffleball. Any neutral boron atoms or molecules not quickly ionized by the high energy free electrons present will exit the Wiffleball and accumulate in the external spaces up to the level permitted by the vigorous vacuum pumping. This is an important consideration as it determines the baseline density that is permissable within the vacuum chamber. Above a certain limit, the neutral gas can breakdown via Pashin arcing (glow discharge) and drain the potential well establishing electron current beyond what the power supply can maintain. This pressure (probably around ~ one Micron or 1/1,000,000,000th of an atmosphere) is way too small for useful rates of fusion (unless you go to Tokamak sizes). The so called Wiffleball effect concentrates the charged particles- ions and free electrons, to such an extent that the useful density of fusable ions within the Wiffleball may be several thousand times this. With the beam- beam fusion that is expected to dominate under these conditions (relative few cool neutrals in the reaction volume to get in the way) the fusion scales as the density squared. So fusion rates may be millions of times greater, or even more in the core if there is significant confluence/ central focus of ions. This allows for high fusion yields in small machines, one of the advertised big advantages of the Polywell.

Another note: With beam - beam fusion dominating over beam - background (neutral) or beam - target fusion, the KE of the protons and Boron11 ions can only be 1/2 of that required for the other fusion interactions, So 200 KeV is required instead of 400 KeV accelerating potential for the same amount of fusion. This eases some of the engineering issues and helps the Bremsstruhlung issue somewhat.

Dan Tibbets
To error is human... and I'm very human.

SymenJ
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Joined: Tue Feb 24, 2015 4:15 pm

Re: Questions regarding the Boron market

Postby SymenJ » Sun Jun 14, 2015 2:30 pm

Dear Dan,

I have some questions regarding your post.

D Tibbets wrote:This is an important consideration as it determines the baseline density that is permissable within the vacuum chamber. Above a certain limit, the neutral gas can breakdown via Pashin arcing (glow discharge) and drain the potential well establishing electron current beyond what the power supply can maintain. This pressure (probably around ~ one Micron or 1/1,000,000,000th of an atmosphere) is way too small for useful rates of fusion (unless you go to Tokamak sizes). The so called Wiffleball effect concentrates the charged particles- ions and free electrons, to such an extent that the useful density of fusable ions within the Wiffleball may be several thousand times this. With the beam- beam fusion that is expected to dominate under these conditions (relative few cool neutrals in the reaction volume to get in the way) the fusion scales as the density squared. So fusion rates may be millions of times greater, or even more in the core if there is significant confluence/ central focus of ions. This allows for high fusion yields in small machines, one of the advertised big advantages of the Polywell.


Can you elaborate more on Pashin Arcing? I do not undestand this principle.
I understand the principle you are stating where neutral atoms will exit the wiffleball. And that therefore there is a high density of charged particles in the centre. But what do you mean with beam- beam fusion?

D Tibbets wrote:Another note: With beam - beam fusion dominating over beam - background (neutral) or beam - target fusion, the KE of the protons and Boron11 ions can only be 1/2 of that required for the other fusion interactions, So 200 KeV is required instead of 400 KeV accelerating potential for the same amount of fusion. This eases some of the engineering issues and helps the Bremsstruhlung issue somewhat.


I do not understand what you are trying to say over here. Do you mean that there are more possible reactions inside the reactor next to the pb11 fusion reaction? How do you come up with these KE values?

Thanks

D Tibbets
Posts: 2769
Joined: Thu Jun 26, 2008 6:52 am

Re: Questions regarding the Boron market

Postby D Tibbets » Sun Jun 14, 2015 7:15 pm

Concerning the arcing question

Error- duplicate.

Dan Tibbets
Last edited by D Tibbets on Sun Jun 14, 2015 7:24 pm, edited 1 time in total.
To error is human... and I'm very human.

D Tibbets
Posts: 2769
Joined: Thu Jun 26, 2008 6:52 am

Re: Questions regarding the Boron market

Postby D Tibbets » Sun Jun 14, 2015 7:16 pm

Concerning the arcing quaestion

-Arc discharge in a gas is governed by a complex relationship between pressure , voltage and separation distance between electrodes. My basic understanding is that a gas- due to partial to nearly full ionization to a plasma, will become a conductor. At high pressures- near atmospheric, it takes a lot of voltage to generate enough plasma, that is free mobile charge carriers, to allow for significant current flow. This would often be called an arc. Best examples may be lightning, or static shocks delivered to your friend. The gas composition also plays a role. Coronal discharge and arcing both play a role. The Van Degraf (sp?) generator is another example. As voltage deepens the voltage needed to 'arc' decreases. Once the arc or conduction path is established, the current flow is dependent mostly on the density/ pressure of the ionized gas. Th current can become impressive if there are enough charge carriers. Again, lightning is a good example of this. As the pressure falls further, the number of free mobile charge carriers decrease and the resultant current decreases, even as the voltage necessary to initiate the arc decreases. There is a point though where the voltage trend reverses. This probably is due to a handful of considerations like Debye shielding, aviable charge carriers, etc. At pressures of around 0-10 Microns, the necessary voltage necessary to initiate and sustain a conductive plasma reverses and increases in an exponential fashion. The voltage you can maintain is such a system is dependent on the density (and type) of gas pressent. At high pressures, the voltage necessary to jump a gap is considerable. Once the gap is bridged though, the amount of ionization, up to the limit of 100 % ionization of a given density of gas, determines the amount of current flowing through the system- gap. Power equals voltage times current, Watts= V * A. Generally a power supply is limited by it's power rating. If the voltage is high, the current has to be low and visa versa. If a power supply can deliver 1000 Watts, then at 100 V , 10 A can be delivered. If the current is increased to 100 A, the Voltage can only be 10 V. This voltage droop is a common aspect of electrical engineering. To control the system you have to control either the voltage, and/ or the current.

Note that arc discharge and glow discharge are sometimes defined differently, but basically is is a matter of degree. Glow discharge can place considerable restraints on the maintainable voltage, though an arc discharge is even more limiting.

http://www.glow-discharge.com/?Physical ... ge_Regimes
https://en.wikipedia.org/wiki/Electric_arc

So, basically, if the gas pressure is too high (the sustainable voltage drops) The potential well depth or magnitude is directly related to the input voltage, so if the sustainable voltage from the power supply drops, so does the potential well.

In the Polywell, it is the electron current that is of most interest for several reasons. Normally, the current travels from a cathode outside the Magrid, to the magrid surface which is grounded or maintained at high positive voltage. You can have a high negative voltage cathode with a low voltage (grounded) magrid or a low negative voltage cathode and a high positive voltage magrid surface voltage, or any combination in between. The difference in potential is what drives the electron acceleration. As advertized, the Polywell is an amplifier when talking about the sustained current of electrons within the magrid. Optimally, the electrons shoot into the machine and bounce back and forth (don't confuse this with magnetic mirror bouncing, which may be somewhat different in details, at least at high Beta. If the electrons bounce around inside 100,000 times before completing their journey to the anode/ ground, then the contained density is the equivalent of ~ 100,000 times greater, This recirculating current within the magrid gives internal densities similar to what a noncontained (one pass directly to the magrid surface) current would if the emitter/ cathode current was increased a 100,000 fold. Instead of perhaps 100 A, you would need 10,000,000 Amps. And, of course a power supply that could maintain the thousands of volts at this current drain. In an operational D-D Polywell,instead of ~ 100,000 volts at 100 A or 10 MW, you would need 100,000 V at 10,000,000 A or 1 TW . Adequate confinement is needed not only for the Q consideration, but also from an engineering perspective of a realistic power supply. For steady state the relationship is straight forward. For pulsed or startup conditions, where the confinement may not be nearly as good, time considerations apply, the difference between Joules and Watts.
With high voltage, some of the electric current may overcome the magnetic shielding and flow directly to the magrid; without the intervening 100,000 passes within the machine. You might be able to maintain a voltage/potential well, but only at reduced voltage.

Also, with sufficient voltage and density the current may arc to other structures- like the grounded vacuum vessel wall, and bypass the magrid entirely. This is completely useless, and drains the power supply as well as screwing up your efforts at reaching a Q greater than one.THere is some leakage of current through the magnetic shielding, or the gap shielding effect (separation distance}at any voltage, but this increases, perhaps exponentially, with increasing voltage at any given density of plasma (or gas that can be ionized to plasma). So, to maintain a target voltage, you need to manipulate the insulation chariteristics, and the tolerable density in the chamber. The magrid should have smooth, gently curving surfaces to avoid electromagnetic field buildup at points, and also, have sufficient magnetic insulation to seriously retard any available low resistance path to grounded or positively charged magrid. Because of these considerations, the voltage* current conditions inside the magrid can be pushed to high levels. This is much more difficult to apply to all of the structures outside of the magrid, so here the density must be kept well below some limit. It turns out that this limit is around 1-10 microns (~ 1-10 millionths of an atmosphers- Using Pascals would be better, but...) Above this density, voltages of interest could not be maintained due to current external structures. The density outside may need to be maintained below 10^19 particles / M^3. With an advertised operating internal density of 10^22 particles/ M^3, the internal magrid volume, can tolerate ~ 1000 times greater densities before insulation breaks down. As the fusion scales as ~ density squared, this concentrating ability (Wiffleball trapping factor) and tolerance of the Polywell volume inside the Magrid allows for ~ 1 million times the fusion rate.Without this concentrating consideration, a Polywell would need to be many times larger than a Tokamak in order to produce useful amounts of fusion, and reaching a Q> one would be very much more difficult. As it is, the sustainable density within the Polywell may result in fusion rates in a given volume to be ~ 60,000 times greater. This is according to Nebil and gives a a general estimate of the size comparison between a Polywell and a Tokamak. This is ~ 60,000 times less volume,or ~ 40 times less diameter. Other considerations may eat into this ratio some, but there is an obvous advantage.
Any of this also applies to P-Boron11 fusion, just the numbers need to be changed some.
In an amatuer Fusor, efforts to push the voltage past a few thousand volts requires the pressure to be in the region of ~ 5-15 Microns. Then the power supplies available can push the voltage up to 10's of KV. For reasonable and detectable D-D fusion to occur this competing relationship needs to be balanced. The fusion cross section goes up with increased voltage (within limits) and the fusion rates goes up with increased density, but the ability to maintain the target voltage goes down with increased density. This is where the Polywell changes the game somewhat. With it's hoped for resistance to higher density voltage drains, and its containment efficiency it is potentially capable of not only reasonably profitable Q's, but also economical scaling of power plants. How this applies to FRC or DPF approaches is uncertain, but it is a tremendous challenge for Tokamaks. The physics may work, but the design must also be economical to build and operate, or it is useless.

Dan Tibbets
To error is human... and I'm very human.

D Tibbets
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Re: Questions regarding the Boron market

Postby D Tibbets » Sun Jun 14, 2015 8:04 pm

Concerning the question about P-B11 voltage-

The 200 KV value comes form the presumed best energy or voltage for the P-B11 reaction. At ~400 KeV the fusion cross section for P=B11 fusion is at it's most attractive point. A 400 KeV P hitting a stationary B11 will work. So will a 200 KeV P- hitting a oppositely moving 200 KeV B11. This is beam- beam fusion as opposed to beam- target (stationary) fusion. The total energy needed to generate this closing energy is the same, but there are other consequences. In a convergent spherical geometry where the ions are moving back and forth, the chances for this head on opposing collision is good. The Polywell may allow for this type of collision to be dominate over other possible fusion collisions. As such, the voltage needed to establish these energies/ closing speed is 1/2. You are accelerating two particles to 200 KeV energies, instead on one particle accelerated to 400 Kev, while the other is held a zero KeV KE. Any combination in between is possible with the same total energy applied. The difference with beam- beam collisions is that the energy per particle is 1/2 of the total, not zero and 100% of the total. The potential well required to accelerate each particle is 1/2 than the beam- target example. Because of this the potential well voltage necessary in the system is 1/2. This is easier from an engineering viewpoint, less voltage to handle- arcing concerns. Also, Bremsstruhlung radiation scales as ~square the KE of the electrons. If you only need to accelerate them to only 200 KeV instead of 400 KeV, then the resultant Bremsstruhlung radiation will be ~4 times less. This may be the difference between the Polywell being a P-B11 fusion machine success or failure. There is no qualifiers or strange interpretation of the published P-B11 fusion cross section charts in this.

There is a condition which I like to speculate on though. Some charts show a P-B11 fusion cross section spike at ~ 120 KeV. This spike is narrow, so to take advantage of it you would need to have the energy spread / thermalization of your plasma to be fairly narrow. But assuming this is possible, it means that in a beam- beam machine, the necessary voltage would only need to be ~ 60 KV for the same rate of fusion at 200 KV Beam-beam or 400 KV beam-target with this resonant cross section peak ignored. At 60 KV (60 KeV particle energies) the Bremsstruhlung would be a further ~ 10 X reduced. Compared to a projected 400 KV beam target machine, the Bremsstruhlung in a 60 KV machine would be ~ 40 times less.

http://physics.stackexchange.com/questi ... nance-peak

This is probably a pipe dream and I am overestimating the effects mildly, but if realized most of the criticisms by Rider and others would be blown out of the water. An imaginary example may be a baseline Polywell operating at 400 KV that burns P-B11 fuel to produce 200 MW of fusion power and consumes ~ 20 MW of electron drive energy and ~ 60 MW of Bremsstruhlung losses. The Q would be a little more than two. This might be borderline useful once conversion to electricity is considered. With a same sized Polywell operating at 60 KV and producing the same amount of fusion, the fusion output would remain at ~ 200 MW, and the electron drive energy may be reduced to only ~ 7 MW and the Bremsstrulung losses would be reduced to ~ 1.5 MW. The Q is now ~ 20. Not only is the energy yield efficiency much better, but engineering concerns about heat loading and X- ray handling are tremendously eased. Now you are in a situation where all of Robert Bussard's dreams about spaceship power and very efficient (and high thrust) rockets are easily (relatively speaking) achieved.

Dan Tibbets
To error is human... and I'm very human.

SymenJ
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Re: Questions regarding the Boron market

Postby SymenJ » Sun Aug 09, 2015 7:02 pm

There is a condition which I like to speculate on though. Some charts show a P-B11 fusion cross section spike at ~ 120 KeV. This spike is narrow, so to take advantage of it you would need to have the energy spread / thermalization of your plasma to be fairly narrow. But assuming this is possible, it means that in a beam- beam machine, the necessary voltage would only need to be ~ 60 KV for the same rate of fusion at 200 KV Beam-beam or 400 KV beam-target with this resonant cross section peak ignored. At 60 KV (60 KeV particle energies) the Bremsstruhlung would be a further ~ 10 X reduced. Compared to a projected 400 KV beam target machine, the Bremsstruhlung in a 60 KV machine would be ~ 40 times less.

http://physics.stackexchange.com/questi ... nance-peak

This is probably a pipe dream and I am overestimating the effects mildly, but if realized most of the criticisms by Rider and others would be blown out of the water. An imaginary example may be a baseline Polywell operating at 400 KV that burns P-B11 fuel to produce 200 MW of fusion power and consumes ~ 20 MW of electron drive energy and ~ 60 MW of Bremsstruhlung losses. The Q would be a little more than two. This might be borderline useful once conversion to electricity is considered. With a same sized Polywell operating at 60 KV and producing the same amount of fusion, the fusion output would remain at ~ 200 MW, and the electron drive energy may be reduced to only ~ 7 MW and the Bremsstrulung losses would be reduced to ~ 1.5 MW. The Q is now ~ 20. Not only is the energy yield efficiency much better, but engineering concerns about heat loading and X- ray handling are tremendously eased. Now you are in a situation where all of Robert Bussard's dreams about spaceship power and very efficient (and high thrust) rockets are easily (relatively speaking) achieved.


Why would this reduce the Bremsstrahlung? And why the factor 10 (or 40)?

Thanks

krenshala
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Re: Questions regarding the Boron market

Postby krenshala » Mon Aug 10, 2015 4:07 pm

The higher the electron potential the greater the Bremsstrahlung output they can generate as they as slowed by other charged particles. If you are using 60kV instead of 120kV, then the electrons have half the potential and should produce much less Bremsstrahlung. It isn't a straight 1:1 ratio, of course, but there are other posts in this section that go over the maths.

D Tibbets
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Re: Questions regarding the Boron market

Postby D Tibbets » Mon Aug 10, 2015 5:35 pm

Bremsstruhlung radiation has benn discusses in other threads. It is a german term for "breaking radiation" It is not the potential of the electrons in the sence of potential energy. It is the energy of the electron that is achieved by accelerating it in electrostatic potential, ie: a potential or voltage of 100,000 volts will accelerate an electron to 100,000 eV of kinetic energy. The potential energy of the electrostatic field is converted to the kinetic energy of the electron.

Bremsstruhlung is the loss of kinetic energy from the electron as it is accelerated past a charged particle. This is generally considered as a fixed charge for convience sake. Here we are interested in the electron being diverted by a ion. The ion may be at the same kinetic energy as the electron but because it weighs ~ 3800 times as much, it is moving proportionatly slower due to the old KE= 1/2 MV^2 relationship. It is moving about 60 times slower than the electron. ecause of this a convient simplification of the problem is to assign a ion as a fixed, non moving charge. This introduces some error but it is small and possibly irrelevant to the final result once multiple particle interactions are considered.

When an electron curves around a ion it changes direction, this fits the definition of acceleration. It is just like gravitational orbit , slingshot effects except the electromagnetic force is tremendously greater than the gravitational force so the effects are much more profound. The kinetic energy of the electron ( mostly, because it is much lighter) is reduced and this kinetic energy is transformed int a light photon or photons. At the energies of the plasma the photon wavelengths is in the X-ray range.

This x=ray leaves the system and so it carries energy out of the system. The KE of the particles- electrons mostly decreases- the plasma cools. The ions also lose kinetic energy because of the decreased kinetic energy of the electrons. Direct Coulomb collisions does not drive this much because with greater difference in the mass or two colliding particles there is less change in momentum of the heavier particle. It is ike comparing a BB traveling at 300 ft/s hitting a boweling ball. There is not much exchange of Kinetic energy. What change there is mostly in the velocity/ KE of the BB. If two bowling balls collide at the same collision speed, things are different. This is why electrons and ions do not exchange much kinetic energy when they collide (have a close electromagnetic mediated encounter). What little energy interaction there is mostly drawn from the electron. If it changes direction it gives up a small amount of energy-. This adds up though when talking about very many such collisions.

How, you might ask, do the electrons heat up the ions if they exchange so little energy with them- the answer, I think, is that it is a mass effect- individual electrons are not effecting individual ions much ( the reverse is more significant- individual ions accelerating individual electrons, all due to momentum). The excess electrons produce a space charge and it is this psace charge that acts on the ions. Thus a potential well created by an excess of energetic electrons can be fairly efficient at accelerating/ heating ions.

The amount of turning or breaking radiation depends on three factors. The charge strength per interaction, the speed of the encounter, and the frequency of the encounters. Note that the speed is proportional to the square of the KE. So a doubling of speed results in a 4 fold increase in KE.
Without further rambling (much) the Bremsstruhlung scales as the density squared (frequency of collisions) the temperature squared (almost, I have seen an exponent of 1.75 used) and the square of the Z or the atomic number of the fully ionized ion. A Boron has a Z of 5 so a single encounter with an electron results in 5^2 or 25 fold increase in Bremsstruhlung radiation per encounter. A temperature of 200 KeV vs 60 KeV has ~ 3.3 ^2 or 10 times as much Bremsstruhlung. Density variations also scale as the square.

Rider analyzed this process in 1995 and based on his calculations, and importantly his assumptions, he concluded that Bremsstruhlung radiation would cool the plasma so much that fusion heating at expected efficiencies could not make up for it, especially for P-B11 fusion and probably D-D fusion as well. D-T might work.

The counter for Rider's criticisms is based on the assumptions- the actual conditions in the machine. With the Polywell, if there is significant confluence of the ions towards the center, the ion densities are greatest in the center. The electrons would experience most of their Bremsstruhlung producing encounters there. But, with a good deep potential well, the electrons are slow in the center, so Bremsstruhung radiation per encounter is exponentially less. On the edge where the electrons are fast, each ion encounter produces more Bremsstruhung , but the encounters are less frequent as the ions are less dense in this area. The final result is a complex interplay and can result in considerably less total Bremmstruhlung losses in the same average temperature and density plasma. The other knob for modifying Bremsstruhlung losses is to dilute the ions with the high Z. The total particle density may be the same and the total fusion rate may not change much, but the electron encounters with the problematic boron ions would be less frequent. This dilution effect may reduce the total Bremsstruhlung losses by a factor of up to about 8 X with a 10 to 1 dilution of boron compared to the protons.

Dan Tibbets
To error is human... and I'm very human.


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