A beam is an ensemble of particles with coordinates that move in close proximity. The study of beams is important because beams can carry two fundamentally important scientific concepts, namely energy and information. Energy has to be provided through acceleration, and the significance of this aspect reflects itself in the name accelerator physics which is frequently used synonymously with beam physics. Information is often generated by utilizing the beam's energy and analyzed in detectors and spectrographs; or it is transported at high rates and is thus relevant for the practical aspects of information science.
 

Beam physics has its historical roots in the seemingly disconnected fields of optics and celestial mechanics, in which nonlinear motion of nearby coordinates is studied; in the former often to high precision over short distances, and in the latter frequently in a more qualitative way over long time scales.  The field made a major step forward with the development of the Cyclotron by E. O. Lawrence, for which he received the Nobel prize in 1939. For the first time it was possible to produce beams of a select kind of ions at significant energy for nuclear study.

The original cyclotron developed by E. O. Lawrence at Berkeley

 

Accelerators of The World  Current Accelerators

Beams have a wide variety of applications. The field of high energy physics or particle physics utilizes both aspects of beams, and they are so important that they even are directly reflected in the names of the field. First, common particles are brought to energies far higher than they usually have on earth. Then this energy is utilized in collisions to produce particles that do not exist in our current natural environment, and information about such new particles is extracted.

 

In a similar way, nuclear physics uses the energy of beams to produce isotopes that do not exist in our natural environment, and extracts information about their properties. It also uses beams to study the dynamics of the interaction of nuclei. Both particle physics and nuclear physics also re-create the state of our universe when it was much hotter, and beams are used to artificially generate the ambient temperature at these earlier times. Two of the currently important questions are related to the understanding of the time periods close to the big bang as well as the understanding of nucleosynthesis, the generation of the variety of currently existing different chemical elements

Spectrometers

 

Scientific Applications  Medical Applications

In chemistry and material science, beams provide tools to study the details of the dynamics of chemical reactions and a variety of other questions. In many cases, these studies are performed using intense light beams, which are produced in conventional lasers, free electron lasers, or synchrotron light sources. Among the various medical applications, particle beams are used for the irradiation of tumors. In our days, the ability to transport information is being applied in the case of fiber optics, where short light pulses provide very high transfer rates. And electron beams transport the information in computer displays and the television tube, one of the most wide spread consumer products.

 

The motion of beams is a prime example of nonlinear dynamics; in fact, beams were one of the first places where chaos was observed.  Also the two historical roots of the field of beam physics continue to enjoy great progress. Modern glass lenses for cameras are better, more versatile, and more wide spread then ever before, and modern electron microscopes now achieve unprecedented resolutions in the Angstrom range. Celestial mechanics has made considerable progress in the understanding of the nonlinear dynamics of planets and the prospects for the long term stability of our solar system.

Nonlinear Dynamics

 

Prospective New Accelerator Projects  New Methods of Acceleration  Education and Outreach

The development of particle accelerators continues at a vibrant pace. The Large Hadron Collider at CERN, Switzerland will reach new energy frontiers; and the planned Next Linear Collider will provide particularly pure new information by colliding electrons and positrons, substantially reducing the numbers of undesirable reaction products.  The muon collider currently being contemplated may allow similarly clean collisions while allowing the beams to be bent due to the significantly reduced losses due to radiation.  To embark towards these new frontiers requires education of  new beam scientists, and the sharing of the exiting goals with the wider community.