System and process for measuring ash in paper

A system for determining the concentration of a mixture wherein the first component includes at least three materials, said system comprising:

• a) source means for producing two beams of x-rays and directing the beams into the mixture, at least one beam having a spectrum of x-rays having a plurality of energies, the first beam including x-rays having an energy above the K-edges of at least two of the materials and the second beam including x-rays having an energy below the K-edges of the same two materials, wherein the energy distributions of the two beams are different and are such that, for each beam, the mass absorption coefficient for the same two materials is substantially equal, but different from the mass absorption coefficient for the third material;
• b) means for receiving the portions of said two beams which are transmitted through the mixture;
• and
• c) means for determining the concentration of the first at least three material component based upon the two directed beams and the transmitted portions of the two beams and not based upon any other x-ray beams.

A process for determining the amount of a first component of a mixture wherein the first component includes variable proportions of three materials, said process comprising the steps of:

• a) directing a first x-ray beam into the mixture, the first x-ray beam having a first spectrum of x-rays having a plurality of energies, the energy distribution of the first spectrum being such that the mass absorption coefficient for the first material is substantially equal to the mass absorption coefficient for the second material and different from the mass absorption coefficient for the third material;
• b) directing a second x-ray beam into the mixture, the second x-ray beam having a second spectrum of x-rays having a plurality of energies, the energy distribution of the second spectrum being such that the mass absorption coefficient for the first material is substantially equal to the mass absorption coefficient for the second material and different from the mass absorption coefficient for the third material, the energy composition of the second x-ray beam being different that the energy composition of the first x-ray beam;
• c) receiving the portions of said first and second x-ray beams which are transmitted through the mixture;
• and
• d) determining the amount of the first component based upon the two directed x-ray beams and the transmitted portions of the two x-ray beams.

A system for determining the amount of a first component of a mixture, wherein the first component includes variable proportions of first, second and third materials, the system comprising:

• a) sources of first and second incident x-ray beams for directing the beams into the mixture, the first and second beams each having a different spectrum of x-rays having a plurality of energies, the beams being such that, for both the first and the second beams, the mass absorption coefficient of the first material is substantially equal to the mass absorption coefficient of the second material but different from the mass absorption coefficient of the third material;
• b) detectors for detecting the portions of the incident first and second beams which are transmitted through the mixture and for generating signals indicative of the intensities of the detected transmitted portions of the x-ray beams;
• and
• C) computing means operatively coupled to the detectors for receiving the signals and computing the amount of the first component based upon the signals.

A system for determining the composition of a component in a mixture, wherein the component includes variable proportions of at least first, second and third materials, the system comprising:

• a) sources of first and second incident x-ray beams for directing the beams into the mixture, the first and second x-ray beams each having a different spectrum of x-rays having a plurality of energies, the beams being such that, for both the first and second beams, the mass absorption coefficient of the first material is substantially equal to the mass absorption coefficient of the second material but different from the mass absorption coefficient of the third material;
• b) detectors for detecting the portions of the incident first and second beams which are transmitted through the mixture and for generating signals indicative of the intensities of the detected transmitted portions of the x-ray beams;
• and
• c) computing means operatively coupled to the detectors to receive the signals and to compute the amount of the third material in the at least three material component based upon the signals.

A process for determining the concentration of a first component of a mixture wherein the first component includes at least three materials, said process comprising:

• a) producing first and second beams of x-rays, at least one beam having a spectrum of x-rays having a plurality of different energies;
• b) producing or filtering at least one of the energy spectra of the first and second beams such that the energy distributions of the first and second beams are different and such that, for each of the first and second beams, the mass absorption coefficients for the same two materials are substantially equal, but different from the mass absorption coefficient for the third material;
• c) directing the first and second beams into the mixture;
• d) receiving the portions of the first and second beams which are transmitted through the mixture;
• and
• e) determining the concentration of the first at least three material component based upon the first and second beams and the transmitted portion of the two beams, and not based upon any other x-ray beams.

A system for determining the concentration of a first component of a mixture wherein the first component includes at least three materials, said system comprising:

• a) source means for producing first and second beams of x-rays, at least one beam having a spectrum of x-rays having a plurality of energies;
• b) means for producing or filtering the energy spectra of at least one of the first and second beams such that the energy distributions of the first and second beams are different and such that, for each of the first and second beams, the mass absorption coefficients for the same two materials are substantially equal, but different from the mass absorption coefficient for the third material;
• c) means for directing the first and second beams into the mixture;
• d) means for receiving the portions of the first and second beams which are transmitted through the mixture;
• and
• e) means for determining the concentration of the first at least three material component based upon the two directed beams and the transmitted portions of the two beams, and not based upon any other x-ray beams.