Conceptual Design of the Argonne 6-GeV Synchrotron Light Source
The Argonne National Laboratory Synchrotron Light Source Storage Ring is designed to have a natural emittance of 6.5 × 10-9 m for circulating 6-GeV positrons. Thirty of the 32 long straight sections, each 6.5-m long, will be available for synchrotron light insertion devices. A circulating positron current of 300 mA can be injected in about 8 min. from a booster synchrotron operating with a repetition time of 1.2 sec. The booster synchrotron will contain two different rf systems. The lower frequency system (38.97 MHz) will accept positrons from a 360-MeV linac and will accelerate them to 2.25 GeV. The higher frequency system (350.76 MHz) will accelerate the positrons to 6 GeV. The positrons will be produced from a 300-MeV electron beam on a tungsten target. A conceptual layout is shown in Fig. 1. Related papers on the Argonne Synchrotron Light Source may be found in references 1-3.
Beam Stability in a 6 GeV Synchrotron Light Source
Future synchrotron radiation sources designed to produce low emittance electron beams for wigglers and undulators will present beam position control problems essentially similar to those encountered by users of existing accelerators,1,2 however tolerances will be tighter due to: 1) the small emittance (7× 10-9 mrad) proposed for the electron beam and the correspondingly small emittances (sizes) of secondary photon beams, 2) the sensitivity of the electron beam closed orbit to quadrupole motion and dipole roll, 3) the high power levels associated with undulator and wiggler beams which will permit (and probably require) high precision and stability of the photon beam position measurements, in addition, 4) the large number of users on the roughly sixty beam lines will demand beams capable of producing the best experimental results. For the present paper, we assume the accelerator control function, which would initially involve making and coordinating all changes, would eventually evolve to setting and verifying the limits of user control: within these limits the beam position would be controlled by users. This paper describes the effects of motion of beam components (quads, rf cavities and dipoles) on the beam and considers the properties of a compensation system from the perspective of users. The system departs from standard practice in considering active perturbation of the electron beam to verify beam corrections. The effects of local closed orbit perturbations to direct undulator beams at different experimental setups are also considered.
The Intuitive Physics of the Equilibrium of the Lever and of the Hydraulic Pressures: Implications for the Teaching of Elementary Physics.
The research field of intuitive physics focuses on discrepancies between 
theoretical and intuitive physical knowledge. Consideration of these 
discrepancies can help in the teaching of elementary physics. However, 
evidence shows that theoretical and intuitive physical knowledge may also 
be congruent. Physics teaching could further benefit from understanding the 
reasons for this congruence. The present study explored these reasons by 
investigating the intuitive physics of the equilibrium of the lever and of the 
hydraulic pressures. It was found that the intuitive-physics law of the lever 
was multiplicative for all participants while the intuitive-physics law of the 
hydraulic pressures differed among participants. Since these laws are 
equally simple and the layman probably has had extensive experience with 
the lever and scarce or no experience with the hydraulic lift, these findings 
support the general hypothesis that physical laws and corresponding 
intuitive-physics laws are congruent when people have had experience with 
the respective phenomena. The results and theoretical considerations suggest 
two strategic principles for teaching elementary physics.