Dr. Gerald P. Jackson

Hbar Technologies, LLC

gjackson2@hbartech.com

antimatterdrive.org

Using Antimatter to Reach the Stars

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Speaker IntroductionPh.D. in accelerator physics at Cornell studying

positron-electron collision (1981-86)

Fermilab Scientist/Project Manager improving antiproton-proton collider performance (1986-2000)

Hbar Technologies, LLC promoting antiproton applications including deep-space propulsion with NIAC, NASA, and DARPA grants (2002-present)

While at Fermilab, concentrated on increasing the production, handling, and storage of antiprotons

Recipient of the IEEE Accelerator Technology Award and a Fellow of the American Physical Society

Currently pursuing crowdfunded research aimed at enhancing antimatter production up to 2 grams per year [www.antimatterdrive.org].

with U.S. Congressman G. William “Bill” Foster

(IL-14)

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Reaching the Stars• This talk is restricted to known, experimentally proven physics:

• Conservation of Momentum

• Conservation of Energy

• Special Relativity

• Particle/Nuclear Physics

• Accelerator Physics

• No magic wands are employed in the extrapolations between current technologies and this vision of robust interstellar travel

• The political, financial, and psychological issues involved in developing a realistic interstellar transportation capability are far more uncertain than the physics issues

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Rocket Equation

� Assumes a constant exhaust velocity ve RELATIVE to the spaceship. Calculates the total change in velocity of the spacecraft once all of the fuel is gone.

� Note that the ratio of initial mass to final mass of the spacecraft is imbedded in a logarithm … the value of this factor only changes by π for a 10x increase in fuel mass.

� If you wish to reach 5% of the speed of light, the exhaust velocity must also approach 5% of lightspeed.

� At 5% of lightspeed, the trip to Proxima Centauri would take roughly 90 years.

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Antimatter-Based Propulsion� Assumption #1: Initial spacecraft will be

unmanned

� Assumption #2: The dry mass of the spacecraft is 10 kg

� Assumption #3: The sail is 5 m in diameter. Spacecraft side of the sail is a 293 micron thick layer of depleted uranium (U238). The far side has a 15 micron thick carbon coating. The total sail mass is 109 kg.

� Assumption #4: Antiprotons drifting into uranium always induces fission.

� Preliminary Result: Approximately 17 g of antihydrogen is needed to reach a spacecraft velocity of 5% lightspeed.

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Peak Production Rate of 2 nanograms per year

Fermilab Antiproton Production (1986-2011)

Change in Slope: Civil Construction & Scale

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• The dominant technical risk associated with antimatter-based deep-space propulsion is the production of sufficient antimatter.

• There are 3 basic improvements needed to increase production from 2 ng/yr to 2 g/yr (a 9-fold enhancement).

1. Antiproton Production

2. Antimatter Accumulation

3. Antimatter Storage

Enhancing Antimatter Production

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• Thick target decelerates protons before antiproton production

• Thick target absorbs and scatters exiting antiprotons

• Only about 1/3 of the protons interact with nuclei, 2/3 only produce heat

Current Antiproton Production Method

This method is highly optimized for colliding particle physics

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• Instead of using a thick target, the concept is to use a very thin target and have the proton beam pass through it multiple times.

• Alternatively, the “thin target” can be a hydrogen gas jet crossing the proton beam path (existing experimental technique) or a Penning Trap containing protons or ionized molecular hydrogen.

• Challenges:

– Target Heating

– Proton deceleration and transverse scattering from electron collisions

Option 1: Antiproton Production Using a Thin Target

AntiprotonBeam

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• Implementation of the above figure would require a symmetric collider: 2 proton beams of the same energy

• In order to create a “beam” of antiprotons, there needs to be a net boost in one direction: this requires an asymmetric collider with 2 unequal proton beams

Option 2: Colliding Proton Beams

AntiprotonBeam

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• In order to antimatter production for deep-space propulsion viable, a 9-fold increase in production rate is needed.

• Research published at Fermilab in 1994 shows that eliminating the thick target would increase antiproton yield by a factor of 1000x (3-fold).

• Instead of using a chain of synchrotrons to accelerate the protons, use a superconducting linear accelerator to gain a 6-fold improvement.

• Thin target experiments can be performed parasitically at Fermilab now!

Projected Antiproton Production Improvement

8-fold EnergyGrowth in 75 Years

Slope Change: Scale / Legal /Civil Construction

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• The only conventional way to contain grams of matter is to form neutral atoms

• Antihydrogen has been formed in flight at Fermilab and at rest in CERN

• The production rates are very small due to insufficient antiproton and positron densities

• A different way of looking at the problem is needed

• We know ion bombardment grows mass on a substrate

• We know that electron bombardment can charge an object

• Do the same thing with antimatter!

Antimatter Accumulation

Current antihydrogen production at CERN

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• Step 1: Levitate a mass of antimatter in the middle of a Penning Trap

• Step 2: Continuously add a stream of antinuclei

• Step 3: Continuously add a stream of positrons (much easier to make than antinuclei).

• Problem: The kinetic energies of the antinuclei and positrons heats up the levitated mass. The only mechanism for heat dissipation is blackbody radiation.

Enhanced Antimatter Accumulation

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• Hydrogen and Helium are only solid at cryogenic temperatures. They are in the upper left corner of the plot

• The black squares are the melting temperatures

• Lithium has a very low melting point

• Beryllium and Boron are much better, but they are difficult to levitate

• Carbon can be easily levitated and has the highest melting point of any element.

Vapor Pressure of Elements

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• Assume an accumulation rate of 10 grams per year

• Assume the levitated mass is spherical (worst case scenario)

• Assume the initial mass is one hour of accumulation, accumulate for one year

• Simulate the elements Lithium, Beryllium, Boron, and Carbon using their known emissivities

• Initial experiments can be performed using normal matter

Accumulation Simulation: Radius

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• Limitation 1: Melting Point

• Limitation 2: Sublimation Rate

• Assume both beams (antinucleiand positrons) have equal kinetic energy when striking the levitated mass

• Lithium is limited to kinetic energies that are not viable

• Carbon can tolerate the highest energy deposition

Accumulation Simulation: Maximum Kinetic Energy

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• For any element above hydrogen, neutrons are needed

• Free antineutron production is useless: they cannot be constrained

• Need to produce antineutrons already bound to antiprotons

• The solution: collide two antiproton beams to produce antideuterons

• Problem: there are other production channels that lower mass efficiency

Antinucleosynthesis: Antineutron Production

H2Bar is an antideuteronH1Bar is an antiproton

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• The plot shows the probability (cross-section) of a given reaction as a function of kinetic energy of a proton beam striking a hydrogen target

• The green dots merging into the black dots on the left side of the plot shows deuteron production

• The red and blue dots are the competing reactions that cause a loss of mass

• 80% of the time an antideuteron is formed by colliding to antiprotons

Antinucleosynthesis: Antideutron Efficiency

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• By colliding two antiproton beams of dissimilar energy (asymmetric collider), a beam of antideuterons is formed.

• This same technique can be used to move up the periodic table

Antinucleosynthesis: Antideutron Beam & Beyond

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Antinucleosynthesis: Antimatter Factory

53 day half-life

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Antinucleosynthesis: Lithium to Carbon

A Lost Antineutron

Overall Theoretical Mass Efficiency: 73%

5700 year half-life

21 min half-life

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• If you were paying attention, you would have noticed that the accumulation of antimatter mass started at an 1-hour mass (1 mg)

• Where does this mass come from?

• Analogy: Sourdough bread production

• The yeast culture used to grow the dough is the original culture used for over 100 years

• Step 1: Grow the mass by adding flour and water

• Step 2: Break off enough for a batch of bread

• Step 3: Repeat Step #1

• Antimatter: The production of the 1st

milligram of anticarbon will be painstaking and slow (could be antiberyllium)

Antinucleosynthesis: Cheating ???

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• Once enough antimatter has been accumulated, a laser can be used to cleave off one end to be used as the starter mass for another accumulation cycle.

• This process can be repeated indefinitely

• The creation, growth, and cleaving of a normal-matter mass of carbon is an early and inexpensive experiment.

Antinucleosynthesis: Starter Mass

• The levitated mass can be spin stabilized using known “rotating wall” techniques

• Most of the nuclei will be deposited on the ends, causing the levitated mass to become cylindrical in shape

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• There are 2 antimatter storage issues

• Issue #1: Levitation during the accumulation process

– In a gravity field

– Levitation mechanism cannot interfere with the antinucleus and positron beams

• Issue #2: Storage during the long interstellar voyage

– Low/No Power for Storage

– Extreme Cold

– Reliability

– Vapor Pressure

Antimatter Storage

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• Diamagnetism is a property shared by most nonmagnetic elements

• When immersed in a magnetic field, these elements reduce the magnitude of the internal magnetic field

• It is possible to produce 3-dimensional stable equilibrium points

Diamagnetic Levitation

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• Instead of continuous beams of C14Bar and positrons, the two beams are bunched

• Between bunches four wires act as a TEM waveguide carrying pulses of electric current

• The associated quadrupole magnetic field configuration levitates the anticarbon mass

Levitation During Accumulation 1

This experimental apparatus is almost complete

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• Confinement along the wires:

– A slight vertical sag in the four wires

– Helmholtz coils wherein the separation between the two coils is larger than the coil radius

Levitation During Accumulation 2

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• Permanent magnets are sufficient to provide passive confinement

• Most permanent magnets have a minimum temperature that must be maintained

• Neodymium (NdFeB) magnets are the strongest commercially available magnets. They have been regularly used at liquid nitrogen temperatures (77ºK)

• Carbon-14 is a radioactive isotope with a half-life of 5700 years

• Anticarbon-14 emits positrons, but the size of the levitated mass

is large compared to the positron range, so the positron kinetic

energy is converted into heat.

• Assuming blackbody radiation as the sole avenue for heat

dissipation, the equilibrium anticarbon temperature, and the

temperature of the nearby containment surfaces, is slightly

greater than that of liquid nitrogen.

Long-Term “Cold” Storage

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• Most of the work presented today was crowdfunded using the KICKSTARTER website.

• We will soon be in a fundraising campaign on Kickstarter. Please look up ANTIMATTERDRIVE under Technology -> Space Exploration. We need to raise $20,000. Subscribe to our mailing list.

• The only NASA funding available for advanced propulsion is through the NASA Innovative Advanced Concepts (NIAC) program. Proposals are due next week. Awards are few and competition is fierce.

Next Steps: Crowdfunding

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• This talk was an introduction to the subject and only scratched the surface of the underlying physics, history, technology, and current calculations

• While the plausibility of producing enough antimatter for deep-space propulsion has not been proven in this talk, the work to date indicates that it is indeed possible to produce antimatter at a rate of at least 2 grams per year

• A technical design report and an experimental roadmap have been started that provide the scientific and technical case and path to plausibility, but writing has been slow due to the need to pay the bills

• Dedicated financial support is needed to finish the job

Conclusions