ADLIB: A simple database framework for beamline codes

There are many well developed codes available for beamline design and analysis. A significant fraction of each of these codes is devoted to processing its own unique input language for describing the problem. None of these large, complex, and powerful codes does everything. Adding a new bit of specialized physics can be a difficult task whose successful completion makes the code even larger and more complex. This paper describes an attempt to move in the opposite direction, toward a family of small, simple, single purpose physics and utility modules, linked by an open, portable, public domain database framework. These small specialized physics codes begin with the beamline parameters already loaded in the database, and accessible via the handful of subroutines that constitute ADLIB. Such codes are easier to write, and inherently organized in a manner suitable for incorporation in model based control system algorithms. Examples include programs for analyzing beamline misalignment sensitivities, for simulating and fitting beam steering data, and for translating among MARYLIE, TRANSPORT, and TRACE3D formats

A feasibility study of beam-chopping at low energy for LANSCE

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). If a beam-chopping system could be developed for the Los Alamos Meson Physics Facility low-energy beam line, there would be potential to operate the Los Alamos Neutron Scattering Center (LANSCE) at much higher power and duty factor and enable such operation with a radio-frequency quadrapole (RFQ) injector. This would greatly extend the capability of the facility. To accommodate LANSCE operation in the new configuration, a chopped beam must be created in the low-energy transport line before the RFQ. Chopping in this region has never been demonstrated and constitutes the major uncertainty of the proposal and determines the critical path for project completion. This study produces a better understanding of the physics involved in chopping an H-beam in a dilute plasma background, and in transporting a chopped H-beam through a neutralized or partially neutralized plasma channel, as well as an estimate for the optimum neutralization strategy for the beam chopping and transport between the ion source and the RFQ

Maximum entropy beam diagnostic tomography

This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs

Optics code development at Los Alamos

This paper is an overview of part of the beam optics code development effort in the Accelerator Technology Division at Los Alamos National Laboratory. The aim of this effort is to improve our capability to design advanced beam optics systems. The work reported is being carried out by a collaboration of permanent staff members, visiting consultants, and student research assistants. The main components of the effort are: building a new framework of common supporting utilities and software tools to facilitate further development; research and development on basic computational techniques in classical mechanics and electrodynamics; and evaluation and comparison of existing beam optics codes, and support for their continuing development. 17 refs

Magnetic optics for proton radiography

High energy protons of 10 to 50 GeV can be used to radiograph dense objects. Because the transmitted beam particles undergo multiple coulomb scattering (MCS) in the object, a magnetic lens system is used to focus the particles exiting each point of the object onto a distant image plane. Without the lens, the MCS would seriously blur the radiographic image. Correlations can be introduced in the illuminating beam to cancel a major part of the chromatic and geometric aberrations in the lens, while providing locations inside the lens where the rays are sorted by MCS angle. This allows the introduction of angle cut apertures to aid material identification. The requirement for a matched multistage lens system with successively smaller angle-cut apertures leads to the use of minus-identity ({minus}I) lenses, in which the angle sorting is in the longitudinal mid plane of the lens, and the exit beam correlations are the same as the input correlations. A single stage {minus}I lens has been successfully tested at Brookhaven with 10-GeV protons and another is being used in dynamic experiments with 0.8-GeV protons at Los Alamos. The resolution achievable at higher energies is briefly surveyed

Noninterceptive transverse-beam measurements

Totally noninterceptive techniques for accurate measurement of transverse beam distributions are required for high-current continuous wave (cw) linacs, such as the Fusion Materials Irradiation Test (FMIT) accelerator. Sensors responding to visible radiation from beam interactions with residual gas and computer algorithms reconstructing spatial and phase space distributions have been implemented. This paper reports on early measurements of the beam from the injector of the prototype FMIT facility at Los Alamos. The first section indicates hardware setup and performance whereas the second section describes the data-processing software. The third section outlines the resultant measurements and further developments are discussed in the fourth section

The accelerator automation application toolkit workshop presentations

Over the past 18 months on the GTA project at Los Alamos, we have been developing tools for building control systems for accelerators. The first tool developed has already demonstrated greatly reduced requirements for conventional computer programming in applying control systems to an accelerator. Even in the early stages, this work has received considerable attention and the system is currently being investigated or used at several other institutes. Further tools are either in the conceptual design, design, or implementation phase. Over the same period, a group at CERN has been developing the ideas and design for a generic software kit for the application of a control system to accelerators. The CERN software kit also addresses the technical management and documentation aspects of control systems. The purpose of the AT Division effort and the CERN kit is to greatly simplify the implementation and lifetime maintenance of an accelerator control system. Experience has shown that accelerator control systems are also applicable to other experimental physics machines. The purpose of the workshop was to explore these ideas and developments as well as other relevant developments in the field, to verify the viability of the concepts, and to develop further the written specifications for some of the components of such a toolkit. We had draft specifications prepared prior to the workshop. 21 figs

Recent Progress on the Marylie/Impact Beam Dynamics Code

MARYLIE/IMPACT (ML/I) is a hybrid code that combines the beam optics capabilities of MARYLIE with the parallel Particle-In-Cell capabilities of IMPACT. In addition to combining the capabilities of these codes, ML/I has a number of powerful features, including a choice of Poisson solvers, a fifth-order rf cavity model, multiple reference particles for rf cavities, a library of soft-edge magnet models, representation of magnet systems in terms of coil stacks with possibly overlapping fields, and wakefield effects. The code allows for map production, map analysis, particle tracking, and 3D envelope tracking, all within a single, coherent user environment. ML/I has a front end that can read both MARYLIE input and MAD lattice descriptions. The code can model beams with or without acceleration, and with or without space charge. Developed under a US DOE Scientific Discovery through Advanced Computing (SciDAC) project, ML/I is well suited to large-scale modeling, simulations having been performed with up to 100M macroparticles. The code inherits the powerful fitting and optimizing capabilities of MARYLIE augmented for the new features of ML/I. The combination of soft-edge magnet models, high-order capability, space charge effects, and fitting/optimization capabilities, make ML/I a powerful code for a wide range of beam optics design problems. This paper provides a description of the code and its unique capabilities