Improved alternating gradient transport and focusing of neutral molecules

Journal Article · Sun Dec 02 04:00:00 EST 2001 · Review of Scientific Instruments

OSTI ID:836657

Kalnins, Juris ^[1]; Lambertson, Glen; Gould, Harvey

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1. LBNL Library

Polar molecules, in strong-field seeking states, can be transported and focused by an alternating sequence of electric field gradients that focus in one transverse direction while defocusing in the other. We show by calculation and numerical simulation, how one may greatly improve the alternating gradient transport and focusing of molecules. We use a new optimized multipole lens design, a FODO lattice beam transport line, and lenses to match the beam transport line to the beam source and the final focus. We derive analytic expressions for the potentials, fields, and gradients that may be used to design these lenses. We describe a simple lens optimization procedure and derive the equations of motion for tracking molecules through a beam transport line. As an example, we model a straight beamline that transports a 560 m/s jet-source beam of methyl fluoride molecules 15 m from its source and focuses it to 2 mm diameter. We calculate the beam transport line acceptance and transmission, for a beam with velocity spread, and estimate the transmitted intensity for specified source conditions. Possible applications are discussed.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Science. Office of Basic Energy Sciences (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 836657
• Report Number(s): LBNL--49088
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 7 Vol. 73
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
74 ATOMIC AND MOLECULAR PHYSICS
BEAM TRANSPORT
DESIGN
ELECTRIC FIELDS
EQUATIONS OF MOTION
FOCUSING
LENSES
METHYL FLUORIDE
MULTIPOLES
OPTIMIZATION
SIMULATION
TRANSPORT
VELOCITY