Ultra-high-mass mass spectrometry with charge discrimination using cryogenic detectors

Patent · Tue Nov 30 04:00:00 EST 1999

OSTI ID:20013988

Frank, M; Mears, C A; Labov, S E; Benner, W H

An ultra-high-mass time-of-flight mass spectrometer is described which uses a cryogenic particle detector as an ion detector with charge discriminating capabilities. Cryogenic detectors have the potential for significantly improving the performance and sensitivity of time-of-flight mass spectrometers, and compared to ion multipliers they exhibit superior sensitivity for high-mass, slow-moving macromolecular ions and can be used as ``stop'' detectors in time-of-flight applications. In addition, their energy resolving capability can be used to measure the charge state of the ions. Charge discrimination is very valuable in all time-of-flight mass spectrometers. Using a cryogenically-cooled Nb-Al{sub 2}O{sub 3}-Nb superconductor-insulator-superconductor (SIS) tunnel junction (STJ) detector operating at 1.3 K as an ion detector in a time-of-flight mass spectrometer for large biomolecules it was found that the STJ detector has charge discrimination capabilities. Since the cryogenic STJ detector responds to ion energy and does not rely on secondary electron production, as in the conventionally used microchannel plate (MCP) detectors, the cryogenic detector therefore detects large molecular ions with a velocity-independent efficiency approaching 100%.

• Sponsoring Organization: US Department of Energy
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 20013988
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CRYOGENIC FLUIDS
DETECTION
MOLECULAR IONS
MONITORS
SUPERCONDUCTING JUNCTIONS
TIME-OF-FLIGHT MASS SPECTROMETERS