High- reflec*vity high- resolu*on X- ray crystal op*cs with diamonds

Transcription

1 High- reflec*vity high- resolu*on X- ray crystal op*cs with diamonds R H E H (kev) Publica*on: Yuri V. Shvyd ko, Stanislav Stoupin, Alessandro Cunsolo, Ayman H. Said and Xianrong Huang. Nature Physics, Vol 6., March 1.

2 Synthe*c Diamonds Put pure carbon under enough heat and pressure- say, degrees Fahrenheit and, atmospheres- and it will crystalize into the hardest material known Replica*ng that environment in the lab isn t easy but it hasn t stopped dreamers from trying Diamond, it turns out, is a geeks best friend. - Wired Magazine, 3

3 Reflec*vity of X- rays with Diamonds (Bragg Diffrac*on) At angles away from grazing incidence, reflec*on occurs as a result of construc*ve interference of waves sca[ered from periodically- ordered atomic planes in crystals: Bragg Diffrac*on. High reflec*vity of crystals is closely *ed to perfect structure; Synthe*c Diamonds are desirable High reflec*vity is achieved when the incidence of photoabsorp*on goes to zero. In reality, photoabsorp*on always exists but close to 1% reflec*vity is achievable if the photoabsorp*on length in the crystal is much larger than the ex*nc*on length High Debye Temperatures/ Low- Z atoms Diamonds are excellent candidate

4 Theore*cal peak reflec*vity, interac*on length and reflec*ons energy bandwidth for x- rays in Bragg backsca[ering from diamond

5 1. Reflec*vity of X- rays in backsca[ering as a func*on of photon energy according to dynamical theory calcula*ons b Reflectivity.6.4 Reflectivity E E H (mev) E E H (mev)

6 Experimental Methods Using synthe*c diamond crystal (9) Bragg reflec*on was observed. To achieve theore*c value the thickness of the crystal, d > L H ~.4 mm Crystal imaging was carried out via synchrotron white- beam topography at the beamline X19C at the Na*onal Synchrotron Light Source Diamond Reflec*vity measurements were carried out with 3.76 kev X- ray at undulator beam line IXS/XOR 3- ID of the Advanced Photon Source

7 Crystal Imaging a y (mm) x (mm) mages of the sample diamond crysta White- beam X- ray topography produced by (133) Bragg reflec*on

8 Experimental Set- up: Reflec*vity Measurement High-heat-load monochromator APD 1 APD (111) Undulator High-resolution monochromator Θ Θ = 1 4 (99) Diamond 3.7 kev X-rays 1 m. m Bandwidth 1 ev Bandwidth 1.7 ev Bandwidth E x = 1 mev xperimental set-up. (See the Methods section for details.) The diamond reflectivity measurements were carried out with E = 3

9 Results: Reflec*vity of X- rays as a func*ons of Energy a b Reflectivity R.8.9 mev E E H (mev) E E H (mev) Counts R (E) = [I R (E) I ]/I (1 A) E E Peak Reflec*vity was found H (mev) to be: Figure Reflectivity of X-rays as a function of photon energy E in R=.89 ±.1; Very close to the expected value of.91 The energy width was found to be.9 mev in agreement with the expected ΔE=.8 mev (given the photon spread of 1 mev) 1, 1, 8, I I R (E)

10 Results: Spectral Width and Peak Reflec*vity as a func*on of Crystal Loca*on a b c y (mm) 4 3 y (mm) y (mm) x (mm) x (mm) x (mm)

11 Conclusions Bragg diffrac*on measurements of reflec*vity and the energy bandwidth show remarkable agreement with theory. High X- ray reflec*vity combined with stability under high- heat- load condi*ons, low thermal expansion make diamond poten*ally valuable for: High- efficiency, high- resolu*on X- ray op*cs for use in next genera*on fully coherent X- ray sources Seeded X- ray free lasers X- ray Fabry- Pérot interferometers