Measurements and characteristics of $$\hbox {Al}_{2}\hbox {O}_{3}{:}\hbox {Cr}^{3+}$$ Al 2 O 3 :

Abstract

Introduction To set up an online proton beam diagnostic system near the neutron production target of China Spallation Neutron Source (CSNS), a luminescence coating sprayed on the target window and a corresponding optic system were fabricated. In the work, the fabrication of Results The emission spectrum excited by 532-nm laser has two obvious peaks at 692.9 nm and 694.3 nm. The samples by flame spraying process with the powders obtained from melting method show higher luminescence intensity than the samples by plasma spraying process. It is observed that the luminescence intensity has some relationships with the alpha phase in the samples, which is deduced from the XRD and photoluminescence tests results. A lower temperature during the flame spraying process will help to keep more alpha phase in the material. The selected four samples show successful fluoresced results in the radioluminescence experiment. Conclusions The luminescence intensity of the coating is improved greatly by the studies on the fabrication process and the characteristics of the samples. The luminescence coating used in beam diagnostics will be fabricated by the confirmed technical process. More works will be continued to improve the characteristics of the luminescence light by controlling Cr concentration and annealing in 1200 ∼ 2000 • C environment in the future.

A novel methodological study for monitoring proton beam spot using back-streaming secondary neutrons from the high-power target

“…multifilament beam monitor faces increased exposure to the high-radiation environment. Another method that involves coating the surface of the target with luminescent material has been used by the SNS [8,9], CSNS [10,11], and European Spallation Source (ESS) [12]. The fluorescence emitted by the interaction between the proton beam and luminescent material is captured by a camera to achieve images of the beam spot.…”