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Lance_E_T_Compte t1_iudydnf wrote

Reply to comment by Busterwasmycat in Is there such a thing as a gamma radiation mirror? by AlarmingAffect0

So that would be for perpendicular incidence. Yes?

If the waves are approaching almost parallel to the surface, wouldn't they "see" the atoms much closer together?

Maybe if you could only reflect for less than 1% incidence, but you could put ~180 of your mirrors?

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kftrendy t1_iuevq1s wrote

That’s a grading-incidence mirror, and it’s used for X-rays. The Chandra and NuSTAR space telescopes are good examples of their use. They’re very low efficiency and heavy, though, and that would get even worse for gamma rays, where the incidence angle would have to be even smaller.

In practice a gamma ray telescope uses collimators (basically blocking all light other than that which is coming from straight on) or coded-aperture masks, which are kind of like pinhole cameras. Neither of those involve reflecting gamma rays though.

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namnit t1_iufz12l wrote

There’s a group at NASA’s MSFC that develop X-ray optics and have done so for the Chandra and IXPE missions, among others. The grazing-incident mirrors are usually in a nested configuration inside cylindrical shells.

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