Patent ID: 6603547
Filing Date: 2003-08-05
Classification: G01N

Abstract:
A method for determining radiation stability of a crystal to radiation of a working wavelength to be employed in a subsequent application, said method comprising the steps of:a) measuring a first absorption spectrum (A) of said crystal, or a cleaved piece of said crystal, of a given thickness (D) over a predetermined wavelength range from a first wavelength (&lgr;1) to a second wavelength (&lgr;2) by means of a spectrophotometer; b) after the measuring of step a), irradiating said crystal, or said cleaved piece of said crystal, with an energetic radiation source with an energy density sufficiently high to form color centers under saturation conditions for a predetermined irradiation time interval; c) after the irradiating of step b), measuring a second absorption spectrum (B) of said crystal or said cleaved piece of said crystal over said predetermined wavelength range from said first wavelength (&lgr;1) to said second wavelength (&lgr;2); d) forming a surface integral of a difference spectrum of said first absorption spectrum and said second absorption spectrum over said predetermined wavelength range from said first wavelength (&lgr;1) to said second wavelength (&lgr;2) and dividing said surface integral by said thickness to obtain a value of said surface integral per unit thickness; and then e) determining an absorption coefficient (&Dgr;k) at said working wavelength from said value of said surface integral per unit thickness.