Photon Factory Activity Report 2017 #35 (2018)

BL-11A/2016G098

Measurement of Beam Coherency at BL11A for Soft X-ray Projection Microscopy
Tatsuo SHIINA1*, Prane Mariel Basco Ong1, Yasuhito KINJO2, and Atsushi ITO3
1Graduate School of Advanced Integration Science, Chiba Univ., Chiba-shi, Chiba, 263-8522, Japan
2
Tokyo Metropolitan Industrial Technol. Res. Inst., Koto-ku, Tokyo 135-0064, Japan3
School of Engineering, Tokai Univ., Hiratsuka-shi, Kanagawa, 259-1292, Japan

1 Introduction
We have developed soft X-ray projection microscopy
system with the correction technique to improve blurred
projection images due to Fresnel diffraction. The iteration
procedure was applied to biological samples and theirsuccessful corrections were achieved with themagnification of more than 300 times for the soft X-raysof 700eV–1keV.[1] Biological images at higher
magnification had less contrast to apply the blurcorrection procedure. To conduct the image correction
procedure efficiently, we improved contrast of biological
specimens by using platinum blue staining and examined
about beam coherency. In this report, we focus on theconsideration of the beam coherency using doublepinholes at BL11A bending magnet beamline.
2 Experiment
The sizes of the double pinholes were 0.5 µmf – 2.0 µmf
and their intervals were 20 µm – 2 µm. The experimental
setup is shown in Fig. 1. The post pinhole was 1 µmf.
Distance between the post pinhole and the double pinhole
was measured with a micrometer whose scale was from
13 mm to 20 mm. The actual distance was 0.5 mm when
the scale was 13 mm. The experiments were conductedwith the various combination of experimental parameters
including photon energy, double pinholes’ size, theirinterval, and the distance described above. Figure 2shows the interferecne fringes with various double
pinhole conditions. In the case of (a) where pinholes’ sizeis 1 µmf with their interval 5 µm under the photon energy
1 keV, 5 interference fringes were observed. The spatial
coherency was estimated as 6 nm (=1240/1keV*5). They
increased to 13 fringes (coherency 16 nm) in the case of(b) with smaller pinholes’ size 0.5 µmf with shorter
interval 2 µm. When the photon energy was lowered to800 eV, the fringe number was decreased as seen in thecase (c) with pinholes’ size 1 µmf and their interval 10µm, and (d) with the size 1 µmf and the interval 2 µm.
The total variation of interference generating conditions
were summarized in Table 1. As a result, the double
pinholes’ size largely affected the beam coherency underthe experimental setup. The coherency did not change at
any observation distances under the condition of the same
pinholes and photon energy, while it was disappeared atwider intervals with smaller distances. It also seems todepend on the post pinhole size and thickness.
References[1] T. Shiina et al., PF Activity Report 2016 #34 B (2017).
http://pfwww.kek.jp/acr/2016pdf/u_reports/pf16b0186.pdf* shiina@faculty.chiba-u.jp

Fig.1 : Experimental setup of double pinhole.

Fig.2 : Interference fringes with some doube pinhole
conditions. Values are pinholes size, interval, photonenergy, and distance.
Table 1 : Variation of interference generating conditions.