Concepts, Problems, & Opportunities for use of Annihilation Energy:

An Annotated Briefing on Near-Term RDT&E to Assess Feasibility

RAND Note N-2302-AF/RC

B. W. Augenstein

HAVING PRODUCED - THEN WHAT?

Deceleration, cooling stages on way to compact storage
- Phase space control, matching (pre-storage to final storage)
- Generally want very low velocity/~stationary particles for insertion into compact storage
- Transition issues ( production compact storage) non trivial
General issues for compact storage techniques
- Characterize storage parameters; special cryogenic/vacuum requirements
- Verify storage lifetimes
- Evaluate handling issues; insertion/extraction rates, losses
- Verify storage design principles
- Estimate storage volume, mass, power implications
- Role of portable traps for early experimental purposes (mini-facilities)
Interesting range of stored material amounts (initial goal)
- ~100 µg - ~10 mg, per compact storage unit
- Many operational applications possible with such amounts

Our problems have only begun after we have initially produced and collected the antiprotons from the production target. Control of the antiparticle phase space volume is critical. Typically, the currently produced antiprotons initially fill a phase space volume of ~10² eV-s at a mean energy of perhaps ~3-12 GeV (dependent on the incident proton energy). A compact storage unit (a "trap") may have a phase space volume perhaps 10⁸ or more down from this. Thus several intermediate stages of deceleration and cooling will be required for matching, and the phase space density must be very carefully controlled. Current plans for antiproton trapping at very low energies propose use of the LEAR ring at CERN, followed by further phase space volume adjustments. (Current proposals to utilize LEAR in this way stem from am Italian team, a University of Washington team, and more recently a LANL team).

Some of the objective measurement issues and considerations for useful compact storage are shown on the chart.

The compact storage units which would be suitable for a wide range of applications are required to store minuscule amounts of material, by conventional standards. To put these amounts in context, remember that these tiny amounts still reflect the following available energy content:

100 µg	---	4.4 metric tons TNT equivalent
1 mg	---	44 metric tons TNT equivalent
10 mg	---	440 metric tons TNT equivalent

The challenge of storage lies in simultaneous satisfaction of several requirements. Requirements include useful product forms and amounts; compact, lightweight storage; long storage lifetimes; manipulation with acceptable losses; and tolerance to specified perturbations (acceleration levels, etc.). For example, we can today build traps storing antiprotons; current techniques and designs for these can prove useful in all requirements save the first (amounts), where we want another factor of perhaps 10⁶ - 10⁷.