Streak Spectroscopy utilizing Meridionally-or Sagittally-bowed Laue Crystals: Three Options

0
0
2657 days ago, 2118 views
PowerPoint PPT Presentation

Presentation Transcript

Slide 1

Streak Spectroscopy utilizing Meridionally-or Sagittally-twisted Laue Crystals: Three Options Zhong National Synchrotron Light Source, Brookhaven National Laboratory Collaborators: Peter Siddons, NSLS, BNL Jerome Hastings, SSRL, SLAC

Slide 2

Agenda The issue we accept X-beam diffraction by bowed precious stones Meridional Sagittal Sagittally bowed Laue gem Focusing system, central length Condition for no centering Three Laue approaches Meridionally bowed, entire bar Meridionally bowed, pencil pillar Sagittally bowed, entire bar Some test confirmation Conclusions

Slide 3

The issue we "expect" Would get a kick out of the chance to quantify, in one single heartbeat, the range of unconstrained x-beam radiation of LCLS Energy transmission capacity: 24 eV at 8 keV, or 3X10 - 3  E/E Resolution of dE/E of 10 - 5 , dE= 100 meV 5 small scale radians difference, or 1/2 mm @ 100 m Source measure: 82 microns N (10 accepted) ph/beat

Slide 4

E 1 R E 2 y O T The general thought Use bowed Laue gems to scatter x-beams of various E to various edge. Go far sufficiently away to permit spatial partition. Utilize a direct or 2-D force finder to record the range. Un-diffracted x-beams go through and can be utilized for "genuine" investigations.

Slide 5

Laue versus Bragg, idealize versus twisted Symmetric Asymmetric q B q B c Bragg c q B q B Laue Order-of-Magnitude Angular acknowledgment Energy data transfer capacity (smaller scale radians) ( E/E) Perfect Crystal a couple of 10's 10 - 4 - 10 - 5 Meri. Twisted Laue xtal 100's-1000's 10 - 3 - 10 - 2 Sag. Bowed Laue xtal 100's 10 - 3

Slide 6

Diffraction of 8-keV X-beams by Si Crystal 511 or 440 can be utilized to give 10 - 5 vitality determination Absorption length ~ 68 microns

Slide 7

Diffraction of X-beams by Bent Laue Crystal What bowing does? A controlled change in point of cross section planes and d-separating of lamellae through the precious stone Lattice-edge change-decides scattering D-dispersing change – Does not influence the vitality determination, as it is coupled to grid edge change … diffraction by lamellae of various d-dividing winds up at various spot on the indicator. Both join to increment shaking bend width - vitality transmission capacity Each lamella carry on like flawless gem – determination Reflectivity: a couple to several percent relies on upon diffraction progression and assimilation Small twisting sweep: kinematic – low reflectivity Large bowing range: dynamic – high reflectivity A lamellar demonstrate for sagittally bowed Laue precious stones, considering flexible anisotropy of silicon gem has as of late been produced. ( Z. Zhong, et. al., Acta. Cryst. A 59 (2003) 1-6)D

Slide 8

Sagittally-twisted Laue precious stone : asymmetry point R s : sagittal bowing span  B : Bragg edge Small impression for high-E x-beams Rectangular shaking bend Wide Choice of , and gem thickness, to control the vitality determination Anticlastic-bowing can be utilized to empower reverse Cauchois geometry Side View Top view

Slide 9

Anisotropic versatile bowing of silicon gem Displacement because of bowing

Slide 10

For Sagittally-bowed gems Lattice-edge change d-separating change Rocking-bend width

Slide 11

For Meridionally-bowed Crystals Lattice-edge change d-dispersing change Rocking-bend width

Slide 12

E 1 E 2 0.5 mm E 1 E 2 E 1 E 2 0.5 mm Three Laue Options Meridionally bowed, "entire" shaft Meridionally bowed, pencil pillar Sagittally bowed, entire bar

Slide 13

E 1 R E 2 y O T Meridionally bowed, "entire" bar How it works Using flimsy (a couple of microns) flawless Silicon gem wafer. Utilize symmetric Laue diffraction, with S 53 " =0, to accomplish consummate precious stone determination Bandwidth: Easily movable by bowing span R, R~ 100 mm to accomplish  E/E~3x10 - 3 . Determination dE/E~10 - 5 for thin gems, T~ termination length, or a couple of microns

Slide 14

E 1 R E 2 y O T Meridionally twisted, "entire" pillar Advantages Wide scope of transmission capacity, 10 –4 - 10 - 2 achievable. High reflectivity ~ 1. Thin precious stone (on the request of annihilation length, a couple of microns) is utilized, bringing about little misfortune in transmitted shaft power. Weaknesses Different shaft areas add to various energies in the range

Slide 15

E 1 R E 2 y O T Meridionally twisted, "entire" pillar Our decision Assuming y=0.5 mm Si (001) wafer 440 symmetric Laue reflection T=5 microns R=200 mm Yields (hypothetically) 3  10 - 3 transmission capacity 2.6  10 - 5 dE/E, overwhelmed by xtal thickness commitment Dispersion at 10 m is 80 mm 10 7 ph/beat on identifier, or 10 4 ph/beat/pixel

Slide 16

E 1 E 2 Meridionally bowed, Pencil Beam How it works Bending of hilter kilter gem causes a dynamic tilting of topsy-turvy cross section planes through bar way. Transfer speed: Adjustable by bowing sweep R, thickness, and asymmetry edge  , conceivable to accomplish  E/E~3x10 - 3 with extensive . y Resolution dE/E is commanded by bar estimate y, dE/E ~ y/(Rtan  B ) Y must be microns to permit 10 - 5 determination

Slide 17

E 1 E 2 Meridionally bowed, Pencil Beam Our pick (out of numerous victors) Si (001) wafer 333 reflection, =35.3 T=50 microns R=125 mm Yields 3  10 - 3 transfer speed 0.8  10 - 5 dE/E, Dispersion at 10 m is 71 mm 10% reflectivity 10 6 ph/beat on locator, or 10 3 ph/beat/pixel Advantages Can perform spectroscopy utilizing a little part of the pillar Disadvantages: Less force because of cut in shaft measure, and regularly 10% reflectivity because of ingestion by thick xtal.

Slide 18

E 1 E 2 0.5 mm Sagittally twisted, entire bar How it works Sagittal bowing causes a tilting of cross section planes The gem is compelled in the diffraction plane, bringing about symmetry over the pillar. Symmetric reflection used to stay away from Sagittal centering, which amplifies the pillar out-of-plane. Transmission capacity: Adjustable by twisting sweep R, thickness, and precious stone introduction.  E/E~1x10 - 3 . Determination dE/E most likely will be commanded by the variety in cross section edge over the bar, must be not as much as Darwin width over a separation of .5 mm.

Slide 19

E 1 E 2 0.5 mm Sagittally bowed, entire pillar Our decision Si (111) wafer 4-2-2 symmetric Laue reflection T=20 microns R=10 mm Yields 0.6  10 - 3 transmission capacity 1  10 - 5 dE/E Dispersion at 10 m is 21 mm 70% reflectivity 10 9 ph/beat on identifier Advantages Uses the vast majority of the photons Disadvantages: Limited data transfer capacity because of the precious stone breaking limit.

Slide 20

Testing with White Beam Four-bar drinking spree Collimated enthusiast of white occurrence bar Observe rapidly sagittal centering and scattering Evaluate twisting techniques: Distortion of the diffracted shaft  variety in the edge of cross section planes

Slide 21

1 cm h=15 mm h=0 h=15 mm h=–12 On the divider at 2.8 meters from precious stone Observation of past information 0.67 mm thick, 001 gem (surface opposite to [001]), Rs =760 mm 111 reflection, 18 keV Focusing impacts: F s =5.7 m concurs with hypothesis of 6 m "Uniform" district, a couple mm high, crosswise over center of gem Dispersion is evident at 2.8 meters from gem. Behind the precious stone

Slide 22

0.11 m 0.37 m 0.75 m Experimental test: sagittally twisted, entire pillar 4-2-2 reflection, (111) gem, 0.35 mm thick, bowed to 500 mm span, 9 keV Exposures with various film-to-gem separate. No sagittal centering because of zero asymmetry. The stature at 0.75 m is bigger than simply behind the precious stone, exhibiting scattering. Contortion is discernible at 1 m, could be a genuine issue at 10 meters. 4-2-2 0.11 m

Slide 23

Measuring the Rocking-bends NSLS's X15A. 111 or 333 flawless gem Si monochromator gives 0.1(v) X 100 mm (h) bar, 12-55 keV (001) precious stone, 0.67 mm thick, 100 mm X 40 mm, twisted to R s =760 mm, dynamic width=50 mm R m =18.8 m (from shaking bend position at various statures) Rocking bends measured with 1 mm wide opening at various areas on gem ( h and x )

Slide 24

0.8 40 keV 30 keV 0.6 25 keV 20 keV Reflectivity 0.4 0.2 0.0 - 200 - 100 0 100 200 Rocking Angle (microradians) Rocking-bend Measurement 111 reflection on the (001) gem,  =35.3 degrees FWHM~ 0.0057 degrees (100 small scale radians) Reflectivities, after remedy by ingestion, are near solidarity (80-90%)  dynamical farthest point Model yields great understanding.

Slide 25

Depth-determined Rocking-bend Measurement Rocking-bend width

Slide 26

Rocking-bend width Two precious stones, numerous reflections tried 18 keV occurrence shaft, 20 micron opening size 0.67 mm thick gem, twisted to Rs=760 mm

Slide 27

Comparison: 001 gem and 111 gem Upper-case Lower-case 100 xtal, 111 reflection  =35 deg S 31 " = - 0.36, S 32 " = - 0.06, S 36 " =0 Upper-case:  0 =92-16=76 rad Lower-case:  0 =-73-16=-89 rad 111 xtal, 131 reflection  =32 deg S 31 " = - 0.16, S 32 " = - 0.26, S 36 " =0 Upper-case:  0 =-73-35=-108 rad Lower-case:  0 =177-35= 141 rad

Slide 28

Future Directions Other gems? Precious stone? for less assimilation Harder-to-break xtals? To build vitality transmission capacity of sagittally-twisted Laue Experimental testing 10 m precious stone to-indicator separation is difficult to find 3-5 m may permit us to persuade you

Slide 29

Summary 3 conceivable answers for the "expected" issue. Alternative 3, sagittally-twisted Laue gem, is our cerebrum tyke. Alternative 1 has better shot. They all require separation of ~ 10 m 2theta of ~ 90 degrees - > level diffraction and square building straight or 2-D coordinating indicator With foundation set up, it is anything but difficult to seek after all choices to see which, if any , works. Average of twisted Laue, boundless handles to turn for the genuine experimentalists … asymmetry edge, thickness, bowing span, reflection, precious stone introduction … We have a greater number of inquiries than answers …

Slide 30

Focal Length Diffraction vector, H , precesses around the bowing hub  alter in course of the diffracted

SPONSORS