  A Mythen detector has been equipped at the beamline 4B9A of Beijing
Synchrotron Radiation Facility, which can be used for in-situ real-time
measurement of X-ray diffraction (XRD) full profiles. In this paper, the
thermal expansion behavior of metal indium has been studied by using the
in-situ XRD technique with the Mythen detector. The indium film was heated from
30 to 160 {\deg}C with a heating rate of 2 {\deg}C/min. The in-situ XRD
full-profiles were collected with a rate of one profile per 10 seconds.
Rietveld refinement was used to extract the structural parameters. The results
demonstrate that the thermal expansion of metal indium is nonlinear especially
when the sample temperature was close to its melting point (156.5 {\deg}C). The
expansion of a-axis and the contraction of c-axis of the tetragonal unit cell
of metallic indium can be well described by biquadratic and cubic polynomials,
respectively. The tetragonal unit cell presents a tendency to become cubic one
with the increase of temperature but without detectable phase change. This
study is not only beneficial to the application of metal indium, but also
exhibits the capacity of in-situ time-resolved XRD experiments at the X-ray
diffraction station of BSRF.
