Abstract
The possibility of applying the Secondary Ion Mass Spectrometry (SIMS) to the determination of bulk Ca of low concentration was studied. Ca containing iron alloys of 2.1 to 210 ppm Ca which is determined by wet analysis, a NBS standard sample (53 mass ppm Ca) for instrumental analysis and 40Ca+ ion doped iron samples (10 and 2000 mass ppm at peak concentration) were analyzed by SIMS.
Analyzing the area of 500×700gμm2 with O2+ primary ion and measuring over 10 spots each sample, one can obtain generally less than 30% for the relative standard deviation of the ion intensity of 40Ca+ normalized with matrix 57Fe+ ion. Analysis of all the three type of samples gave a good linear corelation between relative ion intensity of 40Ca+ and bulk Ca concentration. Under the condition of this work, the relative sensitivity coefficient of Ca to Fe was given 50 and the analytical limit of Ca determination was estimated 0.5 mass ppm Ca.
