Theory and observations support the view that antimatter experiences gravity just as ordinary matter does, but the evidence so far has been indirect. Indeed, some theorists speculate that antimatter is antigravitational, that it may fall “up” instead of “down.” Led by Berkeley Lab physicists, the ALPHA Collaboration at CERN has made direct measurements of the gravitational mass of atoms of antihydrogen, testing how they fall and in what direction.

John Byrd, Derun Li, David Robin, and Carl Schroeder of the Accelerator and Fusion Research Division, Zoltan Ligeti of the Physics Division, and Howard Padmore of the Advanced Light Source are 2012 Fellows of the American Physical Society.

Susan Celniker of Berkeley Lab’s Life Sciences Division and Wim Leemans of the Accelerator and Fusion Research Division have been named 2012 Fellows of the American Association for the Advancement of Science (AAAS).

“Slicing through the electron beam” is the second installment of a two-part feature about new techniques to test beam quality in laser plasma accelerators, including the metric known as slice-energy spread. As Berkeley Lab accelerator scientists meet the challenges of measuring extraordinarily short pulses in a complex environment, the approaching advent of the one-meter-long, 10-billion-electron-volt Berkeley Lab Laser Accelerator (BELLA) brings the promise of “table-top accelerators” closer to realization.

“Emittance” is the first subject in a two-part feature about novel methods devised by Berkeley Lab scientists to test the quality of hard-to-assess beams from laser plasma accelerators. These table-top accelerators propel electron pulses to high energies within a few centimeters, promising far less expensive future accelerators with far less environmental impact than today’s conventional machines.

The laser system for BELLA, the Berkeley Lab Laser Accelerator, recently delivered a petawatt of power – a quadrillion watts – in a pulse just 40 femtoseconds long – a quadrillionth of a second — at a rate of one pulse per second. No other laser system has achieved this peak power at this rapid pulse rate. BELLA’s laser should soon be driving electron beams to 10-billion-electron-volt energies in an accelerator just one meter long.

Berkeley Lab’s NDCX-II, the recently completed second generation Neutralized Drift Compression Experiment, is a compact accelerator whose dense ion beam will be able to deliver a powerful punch for producing warm dense matter – a step on the road to heavy-ion nuclear fusion. Research with NDCX-II will make advances in the acceleration, compression, and focusing of intense ion beams to inform and guide this promising approach to fusion energy power production.

An extraordinary “front end” for the next generation of light sources is taking shape at Berkeley Lab’s Beam Test Facility. APEX, an electron gun that will produce a continuous beam of tight electron bunches at the unprecedented repetition rate of a million bunches a second, is well on the way to becoming the must-have source for superconducting linear accelerators to power future free electron lasers.

Scientists at Lawrence Berkeley National Laboratory have played leading roles in designing and operating ALPHA, the CERN experiment that was the first to capture and hold atoms of antihydrogen, a single antiproton orbited by a single positron. Now, by measuring antihydrogen’s hyperfine structure, ALPHA has achieved another first in antimatter science with the very first measurements of the energy spectrum of an anti-atom.

Clyde Taylor, pioneering scientist and engineer of superconducting magnet technology at Lawrence Livermore and Lawrence Berkeley National Laboratories, died November 16, 2011.