Radiation-induced changes in refractive index and absorption coefficient for several optical materials

Area of Science:

• Materials Science
• Optical Physics
• Radiation Effects

Background:

• Optical materials are crucial for various applications.
• Understanding their response to radiation is essential for performance and longevity.
• X-radiation can induce changes in material properties, affecting their optical performance.

Purpose of the Study:

• To quantify the changes in refractive index and absorptivity of optical materials after X-ray exposure.
• To assess the radiation sensitivity of different optical glasses and calcium fluoride.
• To establish baseline data for radiation-induced optical property changes.

Main Methods:

• Samples of calcium fluoride, several optical glasses (LaK 8, PSK 53, FK 50, SF 8, KzFS 5), and a silica control (SiO(2) Suprasil 2B) were irradiated.
• A radiation dose of 10(5) rad was applied.
• Changes in refractive index and absorption coefficient were measured at specific wavelengths (lambda = 0.5330 microm and lambda = 0.5000 microm, respectively).

Main Results:

• Calcium fluoride exhibited changes of ~5.8 x 10(-6) in refractive index and ~0.1 cm(-1) in absorption coefficient.
• Optical glasses showed varying degrees of change: LaK 8 (~5.8 x 10(-6), ~1.1 cm(-1)), PSK 53 (~4.3 x 10(-6), ~1.7 cm(-1)), FK 50 (~5.1 x 10(-6), ~1.4 cm(-1)), and SF 8 (~6.0 x 10(-6), ~1.0 cm(-1)).
• KzFS 5 showed an absorption coefficient change of ~0.52 cm(-1), while the SiO(2) control sample showed minimal changes below measurement capability.

Conclusions:

• X-radiation induces measurable changes in the refractive index and absorption coefficient of optical materials, including calcium fluoride and various optical glasses.
• The extent of these changes varies depending on the specific material composition.
• These findings are critical for selecting radiation-hardened optical materials for applications involving X-ray exposure.