Thermal desorption gas spectrometer
First Claim
1. A thermal desorption gas spectrometer comprising:
- a vacuum chamber;
a vacuum pump which maintains said vacuum chamber at a vacuum;
a sample stage positioned within said vacuum chamber;
a heater which heats a sample placed on said sample stage;
a mass spectrometer positioned within said vacuum chamber to detect gas which desorbs from said sample; and
a processing circuit which receives an electrical signal output by said mass spectrometer, said processing circuit including;
recording means which continuously records, for each mass of a detected substance, an intensity of said electrical signal as a function of at least one of temperature and elapsed time from a start of heating of said sample to a temperature at which an amount of desorbed gas from said sample becomes extremely small; and
integration means which integrates said intensity of said electrical signal with respect to said function of said at least one of temperature and elapsed time for each mass of said detected substance, and which displays a number of molecules of said detected substances which have adsorbed onto a surface of said sample based on a ratio of said integration of said intensity of said electrical signal to a reference value.
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Accused Products
Abstract
In a thermal desorption gas spectrometer in which samples placed on a sample stage within a vacuum chamber are heated by irradiation with infrared rays, and in which mass is analyzed by detecting desorbed gas by means of a mass spectrometer, there is provided a processing circuit which takes in the electrical signal that is output by the mass spectrometer. The intensity of this signal is continuously recorded, for each mass of a detected substance, as a function of temperature (or of elapsed time) from the start of heating of the sample to the temperature at which the amount of desorbed gas from the sample becomes extremely small. This signal intensity is integrated with respect to temperature (or time) for each mass. The absolute value of the number of molecules can be obtained by comparing these integrated values with the value obtained for a standard sample. A single reference can be set for these measurement results, and an absolute value can be given for the measurement results for each kind of gas that desorbs in the vacuum.
436 Citations
10 Claims
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1. A thermal desorption gas spectrometer comprising:
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a vacuum chamber; a vacuum pump which maintains said vacuum chamber at a vacuum; a sample stage positioned within said vacuum chamber; a heater which heats a sample placed on said sample stage; a mass spectrometer positioned within said vacuum chamber to detect gas which desorbs from said sample; and a processing circuit which receives an electrical signal output by said mass spectrometer, said processing circuit including; recording means which continuously records, for each mass of a detected substance, an intensity of said electrical signal as a function of at least one of temperature and elapsed time from a start of heating of said sample to a temperature at which an amount of desorbed gas from said sample becomes extremely small; and integration means which integrates said intensity of said electrical signal with respect to said function of said at least one of temperature and elapsed time for each mass of said detected substance, and which displays a number of molecules of said detected substances which have adsorbed onto a surface of said sample based on a ratio of said integration of said intensity of said electrical signal to a reference value. - View Dependent Claims (2, 3, 4, 5)
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6. A thermal desorption gas spectrometer comprising:
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a vacuum chamber; a vacuum pump which maintains said vacuum chamber at a vacuum; a sample stage positioned within said vacuum chamber; a heater which heats a sample placed on said sample stage; a mass spectrometer to detect gas which desorbs from said sample; and a processing circuit which receives an electrical signal output by said mass spectrometer, said processing circuit including; recording means which records, for each mass of a detected substance, an intensity of said electrical signal as a function of at least one of temperature and elapsed time from a start of heating of said sample to a temperature at which an amount of desorbed gas from said sample becomes extremely small; and integration means which integrates said intensity of said electrical signal with respect to said function of said at least one of temperature and elapsed time for each mass of said detected substance to provide a number of molecules of said detected substances which have adsorbed onto a surface of said sample based on a ratio of said integration of said intensity of said electrical signal to a reference value. - View Dependent Claims (7, 8, 9, 10)
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Specification