Non-contact surface temperature measurements of nanocrystalline diamond foil under intense ion beams

摘要

An all-reflective telescope based optical pyrometer has been designed and built to collect thermal radiation from a nanocrystalline diamond foil in harsh radiation environment at the Spallation Neutron Source accelerator. The primary use of this instrument is to monitor the foil temperature remotely while it is being bombarded by negative hydrogen ion beams with 1.4 MW power at 1.0 GeV energy. The pyrometer is composed of 4.0" Cassegrain reflector with f/10 configuration, two InGaAs PIN photodiodes, a dichroic mirror, two bandpass filters centered around 1000 nm and 1550 nm, a CMOS camera, and a pinhole mirror with 200 um diameter hole size. It is located 40 m from the foil in the accelerator. The measurement uncertainties demonstrated in this work was better than 2.5% for the temperature range of 1000 K to 2500 K. The design of the optical system, calibration with blackbody source and the temporally resolved measurements made with this pyrometer will be presented.