System and method for sample detection based on low-frequency spectral components
First Claim
1. Apparatus for use in detecting a selected material in a sample, comprising(a) a sample holder for holding the sample, the holder being shielded from ambient electrical and magnetic energy, (b) a noise generator for introducing noise into the sample, without ionizing the sample, (c) a data storage device for storing, for each of one or more preselected materials including the selected material, a data set containing low-frequency spectral components that are (i) in a selected frequency range between DC to 50 kHz, and (ii) characteristic of that material, (d) a detector assembly including a detector coil adjacent the sample holder for producing a time-domain signal having signal components related to low-frequency electromagnetic radiation produced by the selected material in the sample, (e) signal conditioning components for converting the signal from the detector coil to an amplified conditioned signal from which frequency components above a selected frequency have been removed, (f) an electronic computer operably connected to the conditioning components to receive the conditioned signal therefrom, and for processing this signal by:
- (i) retrieving from the data storage device a data set of low-frequency spectral components characteristic of the selected sample material, (ii) filtering the conditioned signal, with such in digitized form, to selectively pass low-frequency spectral components corresponding to those of the retrieved data set;
(iii) cross-correlating the filtered signal from (ii) with the data set of low-frequency spectral components from (i) to produce a frequency-domain spectrum in a frequency range within DC to 50 kHz, and (iv) determining whether the frequency-domain spectrum contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample, and (g) an interface device operably connected to the computer for displaying the output of the processing.
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Abstract
Method and apparatus for detecting a selected material in a sample are disclosed. In the method, the sample is placed adjacent a detector coil, for generating an electromagnetic time-domain signal composed of sample source radiation. The signal is first conditioned to convert the signal to an amplified conditioned signal from which frequency components above a selected frequency have been removed, then filtered to selectively pass low-frequency spectral components that are (i) in a frequency range between dc and 50 khz, and (ii) characteristic of the selected material. The filtered signal is cross-correlated with a data set of low-frequency spectral components that are (i) in a frequency range between dc and 50 khz, and (ii) characteristic of a selected material, to produce a frequency-domain spectrum in the frequency range within DC to 50 khz. This spectrum is then used to determine whether the frequency-domain spectrum contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample.
58 Citations
21 Claims
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1. Apparatus for use in detecting a selected material in a sample, comprising
(a) a sample holder for holding the sample, the holder being shielded from ambient electrical and magnetic energy, (b) a noise generator for introducing noise into the sample, without ionizing the sample, (c) a data storage device for storing, for each of one or more preselected materials including the selected material, a data set containing low-frequency spectral components that are (i) in a selected frequency range between DC to 50 kHz, and (ii) characteristic of that material, (d) a detector assembly including a detector coil adjacent the sample holder for producing a time-domain signal having signal components related to low-frequency electromagnetic radiation produced by the selected material in the sample, (e) signal conditioning components for converting the signal from the detector coil to an amplified conditioned signal from which frequency components above a selected frequency have been removed, (f) an electronic computer operably connected to the conditioning components to receive the conditioned signal therefrom, and for processing this signal by: -
(i) retrieving from the data storage device a data set of low-frequency spectral components characteristic of the selected sample material, (ii) filtering the conditioned signal, with such in digitized form, to selectively pass low-frequency spectral components corresponding to those of the retrieved data set;
(iii) cross-correlating the filtered signal from (ii) with the data set of low-frequency spectral components from (i) to produce a frequency-domain spectrum in a frequency range within DC to 50 kHz, and (iv) determining whether the frequency-domain spectrum contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample, and (g) an interface device operably connected to the computer for displaying the output of the processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for detecting a selected material in a sample, comprising:
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(a) placing the sample adjacent a detector coil, (b) while introducing noise into the sample, and without ionizing the sample, detecting an electromagnetic time-domain signal produced in the detector coil by the sample, (c) conditioning the time-domain signal to convert the signal to an amplified conditioned signal from which frequency components above a selected frequency have been removed, (d) filtering the conditioned time-domain signal to selectively pass low-frequency spectral components that are (i) in a frequency range between DC and 50 kHz and (ii) characteristic of the selected material, (e) cross-correlating the filtered signal from (c) with a data set of low-frequency spectral components that are (i) in a frequency range between DC and 50 kHz, and (ii) characteristic of a selected material, to produce a frequency-domain spectrum in the frequency range within DC to 50 kHz, and (f) determining whether the frequency-domain spectrum contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A system for detecting a selected material in a sample, comprising:
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means for holding the sample adjacent a detector coil, thereby to generate an electromagnetic time-domain signal composed of sample source radiation, without gas chromatography or ion cyclotron resonance, means for introducing noise into the sample during the signal generation, means for conditioning the time-domain signal to convert the signal to an amplified conditioned signal from which frequency components above a selected frequency have been removed, means for filtering the conditioned time-domain signal to selectively pass low-frequency spectral components that are (i) in a frequency range between DC and 50 kHz, and (ii) characteristic of the selected material, means for cross-correlating the filtered signal with a data set of low-frequency spectral components that are (i) in a frequency range between DC and 50 kHz, and (ii) characteristic of a selected material, to produce a frequency-domain spectrum in the frequency range within DC to 50 kHz, and means for determining whether the frequency-domain spectrum contains one or more low-frequency signal components that are characteristic of the selected material, and diagnostic of the presence or absence of such material in the sample. - View Dependent Claims (20, 21)
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Specification