Emissivity measurements of CuCrZr alloy

TL;DR

This study accurately measured the emissivity of CuCrZr alloy using infrared thermography under vacuum conditions, crucial for thermal analysis of beam dump components in high-power accelerators.

Contribution

The paper provides the first reliable emissivity value for CuCrZr alloy, validated against thermocouples, aiding thermal diagnostics in accelerator applications.

Findings

Emissivity of CuCrZr measured as 0.056 ± 0.009.

Infrared thermography validated for temperature measurement up to 650°C.

Vacuum conditions minimized surface oxidation effects.

Abstract

The FRIB heavy-ion accelerator, in user operation since 2022, produces rare isotope beams (RIBs) via interactions of high-intensity stable ion beams with a graphite production target. Approximately 20-40$\%$ of the primary beam power is deposited in the target, while the remaining 60-80$\%$ is absorbed by the beam dump. The minichannel beam dump (MCBD), currently operated at 20 kW and designed for operation up to 50 kW, uses CuCrZr alloy absorber plates. Thermal validation and thermal cycling tests of the MCBD were conducted at the Applied Research Laboratory (ARL) at Pennsylvania State University. Temperature measurements were obtained from an infrared (IR) camera. Since accurate temperature determination requires reliable emissivity values, the emissivity of CuCrZr was measured using the IR camera validated against thermocouple reference temperatures up to $\approx$ 650 $^{o}$C. The measurements were conducted under a vacuum level of $\approx$10$^{-5}$ torr to minimize emissivity variations due to surface oxidation. The emissivity of CuCrZr was determined to be 0.056 $\pm$ 0.009 using a constant fit to the measured data over the surface temperature range from 100-650 $^{o}$C.