Claims
- 1. Apparatus for determining the mean cluster size of clusters, said apparatus comprising:
- a vacuum chamber;
- pick-up cell is disposed within a vacuum chamber;
- a water supply coupled to the pick-up cell for supplying water thereto;
- a pressure gauge coupled to the pick-up cell for measuring the pressure of the water within the pick-up cell and providing pressure reading as output signals therefrom;
- a vacuum pump coupled to the vacuum chamber and pick-up cell that generates a vacuum therein;
- a cluster source for generating a beam of clusters that are passed through the pick-up cell to produce clusters that retain water;
- an analyzer for ionizing and fragmenting the clusters and for producing output signals indicative of intensities of the ionized cluster fragments; and
- a computer for processing the output signals from the analyzer and the pressure readings from the pressure gauge to determine the dependence of fragment intensities on water pressure, and determine the cross-section and mean cluster size of the clusters.
- 2. The apparatus of claim 1 wherein the cluster source is an Argon gas cluster source for generating a beam of Argon gas clusters.
- 3. The apparatus of claim 1 wherein the pressure gauge comprises an ion gauge pressure gauge.
- 4. The apparatus of claim 1 wherein the beam of clusters is passed through the pick-up cell along a central axis thereof.
- 5. The apparatus of claim 1 further comprising a metering valve coupled to the pick-up cell for regulating the pressure in the pick-up cell.
- 6. A method of determining the mean cluster size of clusters, said method comprising that steps of:
- evacuating a vacuum chamber enclosing a pick-up chamber;
- supplying water to the pick-up chamber;
- measuring the water pressure in the pick-up chamber;
- passing clusters through the vacuum chamber and pick-up cell to dope them with water molecules;
- electron impact ionizing the doped clusters to produce doped cluster fragments;
- detecting the electron impact ionized clusters using an analyzer; and
- processing the measured water pressure and the fragment intensities to determine the dependence of fragment intensities on water pressure, and calculate the cross-section and mean cluster size of the clusters.
- 7. The method of claim 6 wherein the step of detecting the electron impact ionized clusters comprises the step of detecting the clusters using a triple quadrupole mass spectrometer.
- 8. The method of claim 6 wherein the step of detecting the electron impact ionized clusters comprises the step of detecting the clusters using a residual gas analyzer.
- 9. The method of claim 6 further comprising the step of:
- regulating the water pressure in the pick-up chamber.
Government Interests
This invention was made with Government support under Contract No. F04611-93-C-0005 awarded by The Department of the Air Force. The Government has certain rights in this invention.
US Referenced Citations (3)