About

Dr. Allen P. Mills, Jr. has pioneered several techniques in the field of positron physics, pioneering numerous techniques. Noteworthy achievements include the development of the single crystal negative affinity positron moderator (1978,9), brightness enhancement of slow positron beams (1980), and the rare gas solid moderator (1986), among others. These groundbreaking innovations open up exciting possibilities, including the potential realization of a Bose-Einstein condensed gas of positronium atoms.

The Positron Laboratory primarily focuses on the intricate realm of dense Positronium (Ps) Physics, with the ultimate goal of fabricating a Bose-Einstein Condensation of Ps. Positronium, resembling a hydrogen-like meta-stable atom composed of an electron and its antiparticle, the positron, exhibits a structure akin to a hydrogen atom. However, due to its inherent instability, it promptly self-annihilates. To extend its lifespan, positronium must be generated at low energy or at the ground state level, allowing it to persist for a maximum of 142 nanoseconds. This duration shortens when the electron and positron spins align in opposite directions, reducing it to a mere 125 picoseconds.

A Positron Accumulator allows us to capture millions of positrons per second. They are emitted when the nucleus of an unstable radioactive atom decays. One such atom is known as Sodium-22, which is the most common source of positrons used in laboratories around the world, including ours. It is usually manufactured (in a nuclear reactor), and experimenters simply purchase sealed capsules containing this material from commercial suppliers (of which there is but one, at the time of writing). These sources have a half-life of 2.6 years, and are limited in their strength; the most one can hope for in a slow positron beam derived from such is about 10 million positrons/second. For many experiments this is sufficient, but not for those requiring a high density of Ps atoms. Here is an example of a Positron Accumulator Scheme. More background and information can be found in Dr. Allen P. Mills's Paper on Chemistry & Physics for Positrons Elsevier - Radiation Physics & Chemistry and by visiting his Google Scholar page.