EMAT sensor FBR ISI&amp L-waves NDE NDE (Non Destructive Evaluation) NDT NDT (Non Destructive Testing) PMN-PT Phased Array R SFR TUCSS dry coupling elevated temperature field-deployable sensor gallium phosphate guided wave guided-wave send–receive harsh environment high temperature high-temperature monitoring high-temperature ultrasonic testing imaging in-service inspection inspection liquid sodium lithium niobate neutron irradiation non-destructive evaluation