| US 7,605,918 B2 | ||
| Spectrometer signal quality improvement via exposure time optimization | ||
| David L. Dalrymple, Fredericktown, Ohio (US) | ||
| Assigned to Thermo Electron Scientific Instruments LLC, Madison, Wis. (US) | ||
| Filed on Mar. 02, 2007, as Appl. No. 11/713,204. | ||
| Claims priority of provisional application 60/778766, filed on Mar. 03, 2006. | ||
| Claims priority of provisional application 60/781256, filed on Mar. 10, 2006. | ||
| Prior Publication US 2007/0216900 A1, Sep. 20, 2007 | ||
| Int. Cl. G01J 3/02 (2006.01); G01J 3/28 (2006.01) | ||
| U.S. Cl. 356—326 | 19 Claims |
| 1. A method for using a spectrometer to collect spectra having an improved signal to noise ratio, the method comprising the
steps of:
a) providing a desired signal to noise ratio SNd for spectra to be collected by the spectrometer;
b) providing a spectrum from the spectrometer, the spectrum having:
(1) an exposure time Ts0;
(2) a signal level Ss0;
(3) a noise level Ns0;
(4) a signal to noise ratio SN0=Ss0/Ns0;
c) providing the maximum signal level Smax allowed by the spectrometer;
d) calculating a limiting exposure time Tslim for the spectrometer, wherein Tslim is approximated by or equal to K*Smax*Ts0/Ss0 (with 0<K<1);
e) calculating a limiting signal to noise ratio SNlim, wherein SNlim is approximated by or equal to SN0*sqrt(Tslim)/sqrt(Ts0);
f) where SNd is less than SNlim:
(1) adjusting the limiting exposure time Tslim, wherein Tslim is approximated by or equal to Ts0*(SNd/Ss0)̂2;
(2) collecting Nexp spectra (with Nexp=1), each spectrum being collected over an exposure time approximated by or equal to
Tslim.
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