I have performed high signal-to-noise (SN /equals/ 300 to 500) observations of interstellar CH/sup /plus// at Lick Observatory and at CTIO of the reddened, early-type stars HD 183143, HD 24432, and HD 157038 in an effort to probe the existence of a /sup 12/C/sup 13/C abundance gradient in our Galaxy.

Early free-electron laser (FEL) development was guided by simple performance criteria based on the number of undulator periods, electron beam quality, and current. The beam quality (emittance and energy spread) was used to characterize the initial distribution of axial electron velocities along the undulator axis. While the emittance and energy spread determine the overall width of the distribution, its detailed shape is also important. As new accelerators are designed specifically for FEL applications, it becomes important to obtain distribution shape information from simulations that include the electron gun, accelerator, and beam transport in addition to the usual electron/optical interaction in the undulator. The distribution at the entrance to the undulator can be calculated from numerical simulations of the cathode emission, acceleration, and transport of an electron beam. We have modeled the beam generation, from cathode emission up to the energy of the accelerator injector, using an axisymmetric, cylindrical geometry particle simulation (DPC). This code solves the relativistic force equation with fields obtained from Maxwell's equations in the Darwin model. The DPC calculation is run repeatedly varying parameters such as accelerating stress, electrode configuration, and axial magnetic field profile until a good match is obtained for the accelerator. The beam exiting …

At Los Alamos National Laboratory a small staff of writers and word processors in the Computer Documentation Group is responsible for producing computer documentation for the over 8000 users of the Laboratory's computer network. The -mdoc macro package was developed as a software tool to support that effort. The -mdoc macro package is used with the NROFF/TROFF document preparation system on the UNIX operating system. The -mdoc macro package incorporates the standards for computer documentation at Los Alamos that were established by the writers. Use of the -mdoc macro package has freed the staff of programming format details, allowing writers to concentrate on content of documents and word processors to produce documents in a timely manner. It is an easy-to-use software tool that adapts to changing skills, needs, and technology. 5 refs.