A Multi-Chamber System for Analyzing the Outgassing, Deposition, and Associated Optical Degradation Properties of Materials in a Vacuum

We report on the Camera Materials Test Chamber, a multi-vessel apparatus which analyzes the outgassing consequences of candidate materials for use in the vacuum cryostat of a new telescope camera. The system measures the outgassing products and rates of samples of materials at different temperatures, and collects films of outgassing products to measure the effects on light transmission in six optical bands. The design of the apparatus minimizes potential measurement errors introduced by background contamination.Comment: 9 pages, 10 figures, published in RSI (minor edits made to match journal accepted version

Magnetically filtered Faraday probe for measuring the ion current density profile of a Hall thruster

The ability of a magnetically filtered Faraday probe (MFFP) to obtain the ion current density profile of a Hall thruster is investigated. The MFFP is designed to eliminate the collection of low-energy, charge-exchange (CEX) ions by using a variable magnetic field as an ion filter. In this study, a MFFP, Faraday probe with a reduced acceptance angle (BFP), and nude Faraday probe are used to measure the ion current density profile of a 5 kW5kW Hall thruster operating over the range of 300–500 V300–500V and 5–10 mg/s5–10mg∕s. The probes are evaluated on a xenon propellant Hall thruster in the University of Michigan Large Vacuum Test Facility at operating pressures within the range of 4.4×10−4 Pa4.4×10−4Pa Xe (3.3×10−6 Torr3.3×10−6Torr Xe) to 1.1×10−3 Pa1.1×10−3Pa Xe (8.4×10−6 Torr8.4×10−6Torr Xe) in order to study the ability of the Faraday probe designs to filter out CEX ions. Detailed examination of the results shows that the nude probe measures a greater ion current density profile than both the MFFP and BFP over the range of angular positions investigated for each operating condition. The differences between the current density profiles obtained by each probe are attributed to the ion filtering systems employed. Analysis of the results shows that the MFFP, operating at a +5 A+5A solenoid current, provides the best agreement with flight-test data and across operating pressures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87898/2/013503_1.pd

Ion-Energy Plume Diagnostics on the BHT-600 Hall Thruster Cluster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76547/1/AIAA-20514-735.pd

Analytic results for Gaussian wave packets in four model systems: I. Visualization of the kinetic energy

Using Gaussian wave packet solutions, we examine how the kinetic energy is distributed in time-dependent solutions of the Schrodinger equation corresponding to the cases of a free particle, a particle undergoing uniform acceleration, a particle in a harmonic oscillator potential, and a system corresponding to an unstable equilibrium. We find, for specific choices of initial parameters, that as much as 90% of the kinetic energy can be localized (at least conceptually) in the `front half' of such Gaussian wave packets, and we visualize these effects.Comment: 22 pages, RevTeX, four .eps figures, to appear in Found. Phys. Lett. Vol. 17, Dec. 200

Vacuum Chamber Pressure Maps of a Hall Thruster Cold-Flow Expansion

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77271/1/AIAA-8973-917.pd

Performance Characteristics of a Cluster of 5-kW Laboratory Hall Thrusters

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76117/1/AIAA-19752-159.pd

Dormant Cathode Erosion in a Multiple-Cathode Gridded Ion Thruster

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76860/1/AIAA-37031-330.pd

Efficiency Analysis of a Hall Thruster Operating with Krypton and Xenon

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76560/1/AIAA-19613-425.pd