  The temperature measurement of material inside of an object is one of the key
technologies for control of dynamical processes. For this purpose, various
techniques such as laser-based thermography and phase-contrast imaging
thermography have been studied. However, it is, in principle, impossible to
measure the temperature of an element inside of an object using these
techniques. One of the possible solutions is measurements of Doppler brooding
effect in neutron resonance absorption (NRA). Here we present a method to
measure the temperature of an element or an isotope inside of an object using
NRA with a single neutron pulse of approximately 100 ns width provided from a
high-power laser. We demonstrate temperature measurements of a tantalum (Ta)
metallic foil heated from the room temperature up to 617 K. Although the
neutron energy resolution is fluctuated from shot to shot, we obtain exactly
the temperature using a reference of a silver (Ag) foil kept to the room
temperature. A free gas model well reproduces the results. This method enables
element(isotope)-sensitive thermometry to detect the instantaneous temperature
rise in dynamical processes.
