Photon Factory Activity Report 2005 #23 Part B (2006)
Instrumentation and TechniqueNE3/2003G150
83

Precision Measurement of the Kr Mössbauer Wavelength
ZHANG Xiaowei*1, Taizou KAWAUCHI2, Hiroyuki FUJIMOTO3, Tatsuo OKANO2
1KEK-PF, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
2
Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba Meguro-ku,
Tokyo 153-8505, Japan
3
Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology,Tsukuba Central 1, Tsukuba, Ibaraki 305-8561, Japan

Experiment
The experiment was carried out at the NE3 station of[1]PF-AR; its experimental arrangement is shown in Fig. 1.
detector1High-resolution
monochromator

APD
detectorcryostat &Krypton
absorber

Si800
Diamond111
monochromator

Si551

Si773
detector2Si400

αtiltlFig. 1 schematic side view of the configuration.

80

68.0X1060

Kr_nuclear scattering 7.9
Kr_electric scattering
7.8

40

7.7
20
7.6
0-202

angular position of Si800 (Sec)47.5

Prompt signal (counts/10s)

Time delayed signal (counts/10s)

Synchrotron radiation was narrowed by a diamondmonochromator, and then by a high-resolution
monochromator containing Si (400) and Si (800) nest
channel-cuts. Kr gas was sprayed through a microchannel plate onto a Be foil at a temperature of 20 K; Krice with uniform thickness was grown on the foil. The Si(800) channel cut of the high-resolution monochromator
was rotated for tuning the x-ray energy to match to theresonance; time-delayed nuclear resonant signal wasdetected by an avalanche photo-diode (APD). One
observation of nuclear resonant scattering is shown in
Fig.2, where there is a peak of the time-delayed signal
around a specific wavelength that contrasts with nochange on the intensity of electronic scattering.
Fig. 2.
Signals of time-delayed
nuclear resonant scatteringand electronic scattering
versus the Si (800) channel
cut angular position.

1020-983

The Kr Mössbauer wavelength was precisely_measured by using two diffractions of (733) and (551) inan FZ silicon crystal. The interval of the two diffraction
peaks was only 0.0631°, which could be easily
determined with high accuracy. The value of the83
wavelength of the Kr first excitation level was0.13184021±4 nm, corresponding to an energy of9404.130±3 eV.

Because the nuclear resonant energy level isinvariable, and its width is a few neV, the intensity
distribution of the time-delayed signal provides theinstrumentation function of the high-resolution
monochromator; its resolution, defined by the half
-6
bandwidth, is 1.5x10 , which corresponds to an energy
band width of 15 meV. By tuning the angular position of
Si (800) at the center of the resonance peak and moving
the APD out of the beam path, the x-ray wavelength ismeasured by a piece of peculiarly cut silicon crystal.
Because the signal of the nuclear resonant scattering
was_weak, two reflection profiles of (733) and (551) weremeasured by electronic scattering. It is considered thatthe central wavelength of the high-resolution
monochromator should be consistent with the nuclear
resonance wavelength.
_Angle b between (733) and (551) is 36.48276°, which
can be calculated from the crystal symmetry. Regarding
the resonant wavelength, the Bragg angles of these two
indexes are 83.435° and 60.082°, respectively. Because
83.435° + 60.082° + 36.48276° is near to 180°, twodiffraction peaks can be observed by rotating the crystal
within about 0.07°.
diffraction intesity (10 A)

Introduction

Si733
15Si55-1
fitting_Si733
fitting_Si55-1

105500
0.24

0.26

0.28

Fig. 3.
Diffractions of_(733) and (551) andtheir Gaussian

fittings.

0.30

angular position of diffraction (deg)Results
The interval of two peaks was measured as 0.06313
degree. From a detailed calculation the Mössbauer
83
wavelength of Kr is 0.13184021(2) nm; in energy unit
[2]
this is 9.404130(2) keV.
References[1] Zhang xiaowei, Tetsuro Mochizuki, Hiroshi Sugiyama,
Shigeru Yamamoto, Hidoo Kitamura, Tatsuya Shioya,Masami Ando, Yoshitaka Yoda, Tetsuya Ishikawa, Seishi
Kikuta and Carlos K. Suzuki: Rev. Sci. Instrum. 63(1992) 404-407[2] ZHANG Xiaowei, Taizou KAWAUCHI, Hiroyuki
FUJIMOTO, Tatsuo OKANO. Jpn. J. Appl. Phys.,Part2,45 (2006) L142.
* zhang.xiaowei@kek.jp

Users' Report247