For x rays the real part of the refractive index, dominated by Rayleigh scattering, is negative and converges to zero for higher energies. For γ rays a positive component, related to Delbrück scattering, increases with energy and becomes dominating. The deflection of a monochromatic γ beam due to refraction was measured by placing a Si wedge into a flat double crystal spectrometer. Data were obtained in an energy range from 0.18 MeV to 2 MeV. The data are compared to theory, taking into account elastic and inelastic Delbrück scattering as well as recent results on the energy dependence of the pair creation cross section. Probably a new field of γ optics with many new applications opens up.
Learning some years back about x-ray optics was an eye-opener for me. I'd never considered anything more sophisticated than pinhole collimation for them.
Then they came up with x-ray lasers ... basically a carbon or metal rod exposed to x-rays!
I once had a character beam lethal microwaves from a maser thru a granite wall to take out a bad guy. The editor is a physicist and made me go back and do some checking on power loss, with the comment "there's dielectrics in them thar rocks."
So off to the U of Md library, where I got deep into the physics. Bottom line for my story, dielectric constant won't make the microwaves be lost, although any boundary will reflect some. Volume resistivity is what soaks up power, and microwaves will carry thru granite just fine.
But the more interesting observation is that the symbol for dielectric constant in the papers I checked used the same as the symbol for index of refraction in glass! Not only may it use the same symbol, but it works almost the same for wavelengths where the material is transparent. Yeah, granite can make a microwave lens.
Tom Ligon wrote:I once had a character beam lethal microwaves from a maser thru a granite wall to take out a bad guy. The editor is a physicist and made me go back and do some checking on power loss, with the comment "there's dielectrics in them thar rocks."
So off to the U of Md library, where I got deep into the physics. Bottom line for my story, dielectric constant won't make the microwaves be lost, although any boundary will reflect some. Volume resistivity is what soaks up power, and microwaves will carry thru granite just fine.
But the more interesting observation is that the symbol for dielectric constant in the papers I checked used the same as the symbol for index of refraction in glass! Not only may it use the same symbol, but it works almost the same for wavelengths where the material is transparent. Yeah, granite can make a microwave lens.