Single-Shot Laser-Driven Neutron Resonance Spectroscopy for Temperature Profiling

TL;DR

This paper introduces a novel single-shot neutron resonance spectroscopy technique driven by laser to measure the internal temperature of materials with high temporal resolution, enabling real-time thermometry in dynamic processes.

Contribution

It presents a new method using neutron resonance absorption with a single laser-driven neutron pulse for internal temperature measurement inside objects.

Findings

Successfully measured temperature of tantalum foil up to 617 K.

Achieved temperature determination despite neutron energy resolution fluctuations.

Validated results with a reference silver foil and a free gas model.

Abstract

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.