Method for acquiring a spectrum

Patent metadata

Field	Value
Publication number	US-2018299384-A1
Application number	US-201815951549-A
Country	US
Kind code	A1
Filing date	Apr 12, 2018
Priority date	Apr 14, 2017
Publication date	Oct 18, 2018
Grant date	—

Abstract

The invention is an iterative method for acquiring a spectrum of a particle that is subjected to an illumination. It may in particular be a Raman spectrum. The method includes successively acquiring spectra that are what are called elementary spectra. These elementary spectra are combined to form a combined spectrum, which may be obtained by summing said elementary spectra. With each elementary spectrum is associated an acceptance criterion that is representative of a variation between said elementary spectrum and the elementary spectra acquired beforehand. Depending on this acceptance criterion, the elementary spectrum is either rejected, or accepted, in which case it is added to the combined spectrum. The invention makes it possible to guard against a degradation of the particle under the effect of an excessive exposure to said illumination.

First claim

1 . A method for acquiring a spectrum representative of a particle, comprising the following steps:
illuminating the particle with a light source; detecting, using a photodetector, light radiation emitted or scattered by said particle under the effect of the illumination and acquiring a spectrum from the detected light radiation;
wherein the method comprises:
i) acquiring a first elementary spectrum and forming an initial combined spectrum from the first elementary spectrum;
ii) acquiring a current elementary spectrum;
iii) taking into account a reference spectrum;
iv) determining an acceptance criterion of the current elementary spectrum, the acceptance criterion corresponding to a deviation between the current elementary spectrum and the reference spectrum;
v) depending on the acceptance criterion:
accepting the current elementary spectrum and updating the combined spectrum by adding the current elementary spectrum to the initial combined spectrum or to the combined spectrum resulting from a preceding iteration;
or rejecting the current elementary spectrum;

vi) reiterating ii) to vi), or exiting from the iteration;
vii) determining a spectrum, representative of the particle, depending on the combined spectrum obtained in v) of the last iteration.

2 . The method according to claim 1 , wherein the reference spectrum is an average spectrum, representative of an average of elementary spectra forming the initial combined spectrum or the combined spectrum resulting from a preceding iteration.

3 . The method according to claim 2 , wherein the average spectrum is established on the basis of a normalization of elementary spectra forming the combined spectrum, depending on an acquisition time of each elementary spectrum forming the combined spectrum taken into account in each iteration.

4 . The method according to claim 1 , wherein, in iv), the acceptance criterion is determined on the basis of a subtraction of the reference spectrum and of the current elementary spectrum, this subtraction preferably being normalized by an indicator of the noise in the reference spectrum and in the current elementary spectrum.

5 . The method according to claim 1 , wherein the reference spectrum is the first elementary spectrum, acquired in i), or an elementary spectrum acquired in a preceding iteration.

6 . The method according to claim 1 , wherein the reference spectrum is a spectrum determined a priori.

7 . The method according to claim 1 , wherein the reference spectrum includes one or more regions of interest of the current elementary spectrum.

8 . The method according to claim 7 , wherein the acceptance criterion is established via a comparison of the current elementary spectrum, in at least one selected region of interest, with the reference spectrum.

9 . The method according to claim 1 , wherein, in v), the combined spectrum is updated with a sum, which is optionally weighted:
of the current elementary spectrum and of the initial combined spectrum or of the combined spectrum resulting from a preceding iteration; or of the current elementary spectrum, to which processing is applied, and the initial combined spectrum or the combined spectrum resulting from a preceding iteration.

10 . The method according to claim 1 , wherein, in vi), the iteration criterion corresponds:
to a preset number of iterations; and/or to the obtainment of a preset number of rejections of current elementary spectra; and/or to the obtainment of a preset number of events in the combined spectrum resulting from v).

11 . The method according to claim 1 , wherein, in ii), each current elementary spectrum is acquired with the same acquisition time.

12 . The method according to claim 1 , wherein, following the first iteration, ii) includes a step of determining an acquisition time of the current spectrum, depending on the value of an acceptance criterion resulting from iii) of a preceding iteration.

13 . The method according to claim 1 , wherein the light source generates an illuminating beam that propagates as far as to the particle, and, following the first iteration, ii) includes a step of determining a power of the illuminating beam depending on the value of an acceptance criterion resulting from iv) of a preceding iteration.

14 . The method according to claim 1 , wherein the photodetector is a Raman spectrometer, the acquired spectrum being a Raman spectrum representative of the particle.

15 . The method according to claim 1 , wherein the photodetector is a fluorescence spectrometer, the acquired spectrum being a fluorescence spectrum of the particle.

16 . A device for analyzing a particle, including:
a light source; a holder configured to receive the particle; a photodetector configured to detect a response signal, emitted by the particle when it is illuminated by the light source and to form a spectrum therefrom; and a processor that is configured to implement i) to vii) of the method according to claim 1 , on the basis of a plurality of elementary spectra acquired by the photodetector, so as to form a spectrum representative of the particle.

Assignees

• Commissariat Energie Atomique

Inventors

• Baritaux Jean-Charles
• Schultz Emmanuelle
• Rebuffel Veronique

Classifications

• G01N21/6486

  Measuring fluorescence of biological material, e.g. DNA, RNA, cells (G01N21/6428 takes precedence) · CPC title

• G01N21/65 Primary

  Raman scattering · CPC title

• G01N2021/656

  Raman microprobe · CPC title

• G01J3/4412

  Scattering spectrometry (particle sizing by light scattering G01N15/0205; optical velocimetry of particles G01P5/20, G01P5/26) · CPC title