Prospects for energy upgrades of the CEBAF accelerator at Jefferson Laboratory are reviewed. The plans begin with the evolutionary upgrade of the maximum energy to 6 GeV, which is already in progress. This would be followed by a construction project to provide energies up to 12 GeV in a remarkably cost-effective manner. A further doubling of the beam energy to 24 GeV is also feasible. The physics that motivates the increase to 12 GeV is reviewed briefly. Then the features of the existing accelerator are outlined with particular emphasis on characteristics of the installed components and the tunnel that impact on possible energy upgrades. Next, the broad approach to increasing the beam energy to 12 GeV, preserving the 100% duty factor and 1 MW beam power of the present accelerator, is outlined. Issues associated with the parallel evolution of the capability of the experimental equipment are reviewed and a ''straw man'' solution is presented to stimulate discussion. Finally, prospects for a future 24 GeV upgrade are presented briefly.
This is the seventh in a series of international workshops on high-power and high-energy density microwave devices for accelerator, plasma physics, and defense applications. The scope of this workshop included accelerators for high energy physics, plasma heating and current drive in controlled thermonuclear fusion research, radar and directed energy/high power microwave systems, THz sources and technologies, and advanced 2D/3D computational tool development.
Recent scientific and technical advances have made it possible to create matter in the laboratory under conditions relevant to astrophysical systems such as supernovae and black holes. These advances will also benefit inertial confinement fusion research and the nation's nuclear weapon's program. The report describes the major research facilities on which such high energy density conditions can be achieved and lists a number of key scientific questions about high energy density physics that can be addressed by this research. Several recommendations are presented that would facilitate the development of a comprehensive strategy for realizing these research opportunities.
The discoveries made in the search for the answers to the questions, 'what is matter made of and how do the parts hold together?" have transformed the material basis and structure of society. Written for the general reader, this book gives an overall picture of the present state of this quest and the directions it might take in the future.
“YOU HAVE CHANGED MY LIFE” is a common refrain in the emails Walter Lewin receives daily from fans who have been enthralled by his world-famous video lectures about the wonders of physics. “I walk with a new spring in my step and I look at life through physics-colored eyes,” wrote one such fan. When Lewin’s lectures were made available online, he became an instant YouTube celebrity, and The New York Times declared, “Walter Lewin delivers his lectures with the panache of Julia Child bringing French cooking to amateurs and the zany theatricality of YouTube’s greatest hits.” For more than thirty years as a beloved professor at the Massachusetts Institute of Technology, Lewin honed his singular craft of making physics not only accessible but truly fun, whether putting his head in the path of a wrecking ball, supercharging himself with three hundred thousand volts of electricity, or demonstrating why the sky is blue and why clouds are white. Now, as Carl Sagan did for astronomy and Brian Green did for cosmology, Lewin takes readers on a marvelous journey in For the Love of Physics, opening our eyes as never before to the amazing beauty and power with which physics can reveal the hidden workings of the world all around us. “I introduce people to their own world,” writes Lewin, “the world they live in and are familiar with but don’t approach like a physicist—yet.” Could it be true that we are shorter standing up than lying down? Why can we snorkel no deeper than about one foot below the surface? Why are the colors of a rainbow always in the same order, and would it be possible to put our hand out and touch one? Whether introducing why the air smells so fresh after a lightning storm, why we briefly lose (and gain) weight when we ride in an elevator, or what the big bang would have sounded like had anyone existed to hear it, Lewin never ceases to surprise and delight with the extraordinary ability of physics to answer even the most elusive questions. Recounting his own exciting discoveries as a pioneer in the field of X-ray astronomy—arriving at MIT right at the start of an astonishing revolution in astronomy—he also brings to life the power of physics to reach into the vastness of space and unveil exotic uncharted territories, from the marvels of a supernova explosion in the Large Magellanic Cloud to the unseeable depths of black holes. “For me,” Lewin writes, “physics is a way of seeing—the spectacular and the mundane, the immense and the minute—as a beautiful, thrillingly interwoven whole.” His wonderfully inventive and vivid ways of introducing us to the revelations of physics impart to us a new appreciation of the remarkable beauty and intricate harmonies of the forces that govern our lives.
Guesstimation is a book that unlocks the power of approximation--it's popular mathematics rounded to the nearest power of ten! The ability to estimate is an important skill in daily life. More and more leading businesses today use estimation questions in interviews to test applicants' abilities to think on their feet. Guesstimation enables anyone with basic math and science skills to estimate virtually anything--quickly--using plausible assumptions and elementary arithmetic. Lawrence Weinstein and John Adam present an eclectic array of estimation problems that range from devilishly simple to quite sophisticated and from serious real-world concerns to downright silly ones. How long would it take a running faucet to fill the inverted dome of the Capitol? What is the total length of all the pickles consumed in the US in one year? What are the relative merits of internal-combustion and electric cars, of coal and nuclear energy? The problems are marvelously diverse, yet the skills to solve them are the same. The authors show how easy it is to derive useful ballpark estimates by breaking complex problems into simpler, more manageable ones--and how there can be many paths to the right answer. The book is written in a question-and-answer format with lots of hints along the way. It includes a handy appendix summarizing the few formulas and basic science concepts needed, and its small size and French-fold design make it conveniently portable. Illustrated with humorous pen-and-ink sketches, Guesstimation will delight popular-math enthusiasts and is ideal for the classroom.
The year 1969 saw the publication of the first results indicating that hard scattering centres exist deep inside protons. A collaboration between the Stanford Linear Accelerator Center (SLAC) and the Massachusetts Institute of Technology was using SLAC's new high-energy electron LINAC to pioneer a rich new field in the study of the nucleus--deep inelastic scattering. Their measurements revealed that nucleons are made up of point-like particles, which Richard Feynman dubbed ''partons''. Thirty-five years on, studies of the parton-nature of the nucleus continue, not only at the traditional high-energy centres, but also at lower-energy laboratories, and in particular at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Virginia. Jefferson Lab is home to the Continuous Electron Beam Accelerator Facility (CEBAF). Its main mission is to explore the atomic nucleus and the fundamental building-blocks of matter. As part of this mission, researchers there study the transition from the picture of the nucleus as a bound state of neutrons and protons to its deeper structure in terms of quarks and gluons--in other words, the transition from the hadronic degrees of freedom of nuclear physics to the quark-gluon degrees of freedom of high-energy physics. In exploring this transition, a wide range of experiments has been performed, from measurements of elastic form factors at large momentum transfers to studies of deep inelastic scattering. An array of spectrometers together with electron-beam energies of up to 5.7 GeV has allowed the laboratory to make significant contributions to this field. This article describes three experiments, each aimed at improving our understanding of a different aspect of the partonic nature of matter. The first, a classic deep inelastic scattering experiment, seeks to further our understanding of the composition of nucleon spin. The second experiment studies the concept of quark-hadron duality--a link between the deep inelastic region and the resonance region. The third experiment uses the atomic nucleus as a laboratory to improve understanding of the propagation and hadronization of quarks. Jefferson Lab's ability to perform this range of measurements is illustrated by the plot from the CEBAF Large Acceptance Spectrometer (CLAS) shown on the cover of this magazine, where the hadronic resonance peaks are seen to be washed out as one goes from the delta resonance around 1.2 GeV to higher invariant masses and into the deep inelastic scattering realm of quarks and gluons.
Prospects for elastic scattering off few-body systems with higher beam energies at Jefferson Lab are presented. The elastic structure function A(Q2) data of the deuteron and the helium isotopes can be extended to very large momentum transfers using reasonable beam times and planned spectrometer upgrades. The new measurements will be critical in the search for a transition between the conventional meson-nucleon and the quark-gluon constituent descriptions of the few-body systems.
