Keith Drake

3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies

A hypervelocity dust accelerator for studying micrometeorite impacts has been constructed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) at the University of Colorado. Based on the Max-Planck-Institüt für Kernphysik (MPI-K) accelerator, this accelerator is capable of emitting single particles of a specific mass and velocity selected by the user. The accelerator consists of a 3 MV Pelletron generator with a dust source, four image charge pickup detectors, and two interchangeable target chambers: a large high-vacuum test bed and an ultra-high vacuum impact study chamber. The large test bed is a 1.2 m diameter, 1.5 m long cylindrical vacuum chamber capable of pressures as low as 10(-7) torr while the ultra-high vacuum chamber is a 0.75 m diameter, 1.1 m long chamber capable of pressures as low as 10(-10) torr. Using iron dust of up to 2 microns in diameter, final velocities have been measured up to 52 km/s. The spread of the dust particles and the effect of electrostatic focusing have been measured using a long exposure CCD and a quartz target. Furthermore, a new technique of particle selection is being developed using real time digital filtering techniques. Signals are digitized and then cross-correlated with a shaped filter, resulting in a suppressed noise floor. Improvements over the MPI-K design, which include a higher operating voltage and digital filtering for detection, increase the available parameter space of dust emitted by the accelerator. The CCLDAS dust facility is a user facility open to the scientific community to assist with instrument calibrations and experiments.

On the applicability of laser ionization for simulating hypervelocity impacts

In-situ measurements, the direct interception and analysis of dust particles by spacecraft-based instrumentation, provide insights into the dynamical, physical and chemical properties of cosmic dust. The most sensitive detection methods for dust particles in space are based on impact ionization. Laser ionization is used for the test, development, and calibration of impact ionization instruments and to complement laboratory based particle impact experiments. A typical setup uses a 355 nm Nd-YAG laser with a pulse length of about 5 ns. It is necessary to investigate the properties of both processes with respect to their comparability. A study was performed to find out to what extent laser ionization can be used to simulate impact ionization. The findings show that laser ionization and impact ionization show similarities, which can be used to test the functionality of dust impact detectors, especially time-of-flight instruments. Our paper provides information on what extent these similarities hold and where ...

Novel instrument for Dust Astronomy: Dust Telescope

The analysis of dust particles in space can tell us about their origin and interaction with the space environment that helps understanding the evolution of the solar system and the universe.1 2 There has been a significant advancement in dust detector/analyzer technology over the past decades; going from simple impact counters to the measurement of chemical composition and accurate dust trajectory determination. The Dust Telescope (DT) is the state of the art instrument that combines the Dust Trajectory Sensor (DTS) and the Chemical Analyzer (CA). A laboratory prototype of DT has been built and tested at the Heidelberg dust accelerator facility. The instrument combines a large target area, high mass resolution, wide dynamic range and trajectory measurement with accuracy better than 1% in speed and 0.1° degree in directionality for micron and submicron sized particles. Potential applications of the DT include the analysis of interstellar and interplanetary dust present in our Solar System, and the surface composition analysis of airless bodies such as the Moon, Europa, Ganymede, Enceladus or the Martian satellites.

Characteristics of a new dust coordinate sensor

A new in-beam dust coordinate sensor (DCS) at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) dust accelerator facility has been constructed and is now in use. The dust sensor operates by measuring the image charges induced on two planes of wire electrodes by passing charged dust particles. Applications for the DCS include the quantitative evaluation and improvements of the focusing and steering elements of the accelerator, and the correlation of particle velocity and mass with impact sites using precision particle location. For focusing and steering improvements, particle positions to 0.25 mm are plotted in real-time. It is possible to determine a typical particles position within the beamline to < 0.1 mm. The design, simulation and results of the DCS are further discussed.

Frontiers in In-Situ Cosmic Dust Detection and Analysis

In‐situ cosmic dust instruments and measurements played a critical role in the emergence of the field of dusty plasmas. The major breakthroughs included the discovery of β‐meteoroids, interstellar dust particles within the solar system, Jovian stream particles, and the detection and analysis of Enceladuss plumes. The science goals of cosmic dust research require the measurements of the charge, the spatial, size and velocity distributions, and the chemical and isotopic compositions of individual dust particles. In‐situ dust instrument technology has improved significantly in the last decade. Modern dust instruments with high sensitivity can detect submicron‐sized particles even at low impact velocities. Innovative ion optics methods deliver high mass resolution, m/dm>100, for chemical and isotopic analysis. The accurate trajectory measurement of cosmic dust is made possible even for submicron‐sized grains using the Dust Trajectory Sensor (DTS). This article is a brief review of the current capabilities of...

The Dust Accelerator Facility of the Colorado Center for Lunar Dust and Atmospheric Studies

The NASA Lunar Institutes Colorado Center for Lunar Dust and Atmospheric Studies has recently completed the construction of a new experimental facility to study hypervelocity dust impacts. The installation includes a 3 MV Pelletron, accelerating small particles in the size range of 0.1 to few microns to velocities in the range of 1 to 100 km/s. Here we report the capabilities of our facility, and the results of our first experiments.