Photon Factory Activity Report 2004 #22 Part B (2005)
Instrumentation and TechniqueNE1/2002G280

Reproducibility of Gd Kβ X-ray fluorescence intensity measurement
by Compton spectrometer at BL-NE1A1
Masaaki HARADA1, Masahiko SHOJI2, Hiroshi KAWATA3, and Kenji SAKURAI*2
1
Fukuoka University of Education, Munakata, Fukuoka 811-4192, Japan
2
National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan3
Photon Factory, Tsukuba, Ibaraki 305-0801, Japan
Introduction
Gadolinium is a very important element in thedevelopment of lasers, phosphors and magnetic materials.
The Compton spectrometer at BL-NE1A1 can be used torecord the element’s K-X-ray fluorescence spectra, which
are in quite a high energy region [1]. In this study, thereproducibility of the measurements has been investigated.
Experimental
The sample measured was a Gd metal powder(Furuuchi Chemical Corp.) cast into a pellet (10 mmφ x 5mm thick). The fluorescent X-rays were dispersed by aSi(422) analyzer and observed at a scattering angle of 160
degrees, and were recorded on the image plate (FUJI MS2025). The incident X-ray energy was set at 70 keV
Results and Discussion
Figure 1 shows typical K-X-ray fluorescence spectra ofa metallic gadolinium pellet. In addition to the Kα andKβ lines of Gd, a Compton scattering peak was observedat around 55 keV. The K lines of Ta, which is contained
as an impurity in gadolinium powder, were also seen. In
the present study, particular interest was paid to the Kβlines, which are shown in the inset of Fig.1, mainly
because of the possibility of chemical characterization [1].
The energy resolution was ca 75 eV at around Gd Kβ1. Inorder to evaluate the reproducibility of the spectra, theexposure was repeated with almost the same conditions.
The measurement was done so that the intensity of Kβ1
became as close as possible to the maximum recordable
values for the imaging plate, and the measuring time was
3-7 hours, depending on the ring current and the lifetime.
The number of photons of the incident X-rays was
KβData12345Kβ561048
510Kβ2

KOII,II4950

ComptonTa Kα455055

Figure 1 The K spectrum of a Gd metal pellet.

Users' ReportΚβ1/ Κβ22.3823
2.38172.3784
2.36882.3742

Κβ1,3,5 / Κβ2,ΟΙΙ,ΙΙΙ
3.48983.49993.45383.46923.4759Kβ3+Kβ1 +Kβ51060

Kβ1Kβ35Kβ2+KOII,III
Kβ50440IC
34115462
33964785
315821302739712524488254

15Kβ3

Energy (keV)272

Table 1 Reproducibility of the intensity ratios of Gd Kβspectra. The normalizing factor corresponding to theintegration of incident X-ray intensity (IC) is alsotabulated.

Kβ11010References[1] M. Harada, H. Eba, M. Shoji, K. Sakurai, I.
Matsumoto, and H. Kawata, Photon Factory Activity
Report #20, 287 (2003).
*sakurai@yuhgiri.nims.go.jp

Normalized Intensity

Fluorescence Intensity (a.u.)Kα7monitored by an ionization chamber and thecorresponding digital values were added up during theexposure. Figure 2 shows the intensities of Kβ peaks
normalized by value. Although the intensities are still
scattered, with a range of ±5%, if we take the ratios
between the intensities, this stabilizes the deviation towithin a range of ±1% as listed in Table 1. The resultsuggests that it is possible to detect the change of spectra
due to chemical effects etc., if the variation of theintensity ratio is over several %. The authors would liketo thank Professor N. Shiotani for his kind assistanceduring the experiment.

123Kβ2KOII,III
45

Data Number
Figure 2 Reproducibility of the intensities of GdKβ lines.