United States Patent  [ii] Patent Number: 4,542,293
Fenn et al.  Date of Patent: Sep. 17, 1985
 PROCESS AND APPARATUS FOR
CHANGING THE ENERGY OF CHARGED
PARTICLES CONTAINED IN A GASEOUS
 Inventors: John B. Fenn, Branford, Conn.;
Masamichi Yamashita, Tokyo, Japan;
Craig Whitehouse, Branford, Conn.
 Assignee: Yale University, New Haven, Conn.
 Appl. No.: 486,642
 Filed: Apr. 20, 1983
 Int. CU B01D 59/44; H01J 49/00
 U.S. CI 250/288; 328/233
 Field of Search 250/288, 289, 423 R,
250/423 F, 424, 425; 313/359.1, 360.1, 361.1,
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FOREIGN PATENT DOCUMENTS
1584459 2/1981 United Kingdom .
Malcolm Dole, L. L. Mack, and R. L. Hines; "Molecular Beams of Macroions", 9/1/68, vol. 49, No. 5, The Journal of Chemical Physics.
K. T. Whitby, "Generator for Producing High Concen
trations of Small Ions", 12/61, vol. 32, No. 12, The Review of Scientific Instruments. Arthur Kantrowitz and Jerry Grey, "A High Intensity Source for the Molecular Beam, Pt. 1 Theoretical", 5/51, vol. 22, No. 5, The Review of Scientific Instruments.
Primary Examiner—Alfred E. Smith
Assistant Examiner—Vincent J. Lemmo
Attorney, Agent, or Firm—Birch, Stewart, Kolasch &
A method of changing the energy of charged particles contained in a gas comprises allowing the gas to flow into a region of reduced pressure through a tube like member so that viscous forces exerted on the charged particles by the flowing gas molecules determine the kinetic energy of the charged particles. A potential gradient is maintained along the length of the tube so that the potential energy of the charged particles is changed as they pass through the tube. At the end of the tube a free jet expansion occurs so that the kinetic energy of the charged particles is no longer determined by the flowing gas, so that they can be accelerated to any desired kinetic energy by means of another potential gradient.
The invention can be used to interface any high pressure ion source to a magnetic sector mass spectrometer, or to permit the operation of an electrospray ion source with an earthed inlet capillary with either a quadrupole or a magnetic sector mass spectrometer.
38 Claims, 4 Drawing Figures