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

Patent ·
OSTI ID:872715

An ultra-high-mass time-of-flight mass spectrometer using 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%.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
DOE Contract Number:
W-7405-ENG-48
Assignee:
Regents of University of California (Oakland, CA)
Patent Number(s):
US 5994694
OSTI ID:
872715
Country of Publication:
United States
Language:
English

References (4)

Cryogenic particle detectors journal March 1996
Simultaneous measurement of flight time and energy of large matrix-assisted laser desorption ionization ions with a superconducting tunnel junction detector journal October 1997
Biopolymer mass spectrometer with cryogenic particle detectors journal February 1996
Detection of single macromolecules using a cryogenic particle detector coupled to a biopolymer mass spectrometer journal June 1996