1. Mitglied der Helmholtz-Gemeinschaft POW-HOW guide investigation Up-date Nicolò Violini Lund, 24 th October 2012

2. outline relaxing the eye-of-the-needle Double elliptic guide: long axis 18m, short axis 3cm 1cm 2 openings Square cross section Octogonal cross section + straight in the middle (1.5) 2 cm 2 openings Square cross section Octogonal cross section + absorbing end 2m and 4m REFERENCE CASE: Single elliptic guide from Copenaghen group With/out 1cm 2 slit in front of the sample Hystory of learned things

3. W5.2 POW-HOW bi-spectral powder diffractometer IKON-1 Lund 8-Sept-2011 Neutron guide conceptsEye-of the-needle + Ellipse multiple wavelength frame for optimal length and bandwidth Pulse chopper pair 75 m n = 2n = 2

4. W5.2 POW-HOW bi-spectral powder diffractometer Neutron guide concepts Eye-of the-needle + double Ellipse IKON-2 Lund 9./10.-Feb-2012 pulse chopper bandwidth chopper exchangable parts moderator bi-spectral (POWTEX / Selene) counter rotating 1 cm 1o1o backtracing

5. Coma-aberration homogeneous correction Back-tracing method to optimise progressive coating ‘optimal’ short axis found for long axis 50m, 75m, 150m 1x1cm 2 eye-of-the-needle not enough to mirror in 1x1cm 2 sample size with 0.5° FWHM Figure-of-merit still not proper defined at that time Systematic performance study of double elliptic guides ESS S&S Berlin 17/20-Apr-2012

6. Comparison by brilliance transfer single ellipse versus double ellipse relaxing the eye-of-the-needle square versus octogon

7. outline relaxing the eye-of-the-needle Double elliptic guide: long axis 18m, short axis 3cm 1cm 2 openings Square cross section Octogonal cross section + straight in the middle (1.5) 2 cm 2 openings Square cross section Octogonal cross section + absorbing end 2m and 4m REFERENCE CASE: Single elliptic guide from Copenaghen group With/out 1cm 2 slit in front of the sample History of learned things

8. 1cm 0.5° What to show? Schematic view of the guide/s Coating distribution in colour scale Brilliance transfer as function of wavelength Brilliance transfer as function of vert position Brilliance transfer as function of vert divergence 2D pos hor div vs hor pos vert div vs vert pos 2D div Simulations Data at 0.4cm 2 0.7cm 2 1cm 2

9. 1) a=38.85m b=3.2cm squarecross section 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 2x2 cm 2

10. 1) a=38.85m b=3.2cm square1) a=38.85m b=3.2cm square+ slit 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 2x2 cm 2 1x1 cm 2

11. 2) a=18m b=3cm square 1x1 cm 2 3x3 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 last 2m absorbing

12. 2) a=18m b=3cm octogonal 1x1 cm 2 3x3 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 last 2m absorbing

13. 2) a=18m b=3cm octogonal + straight square 1x1 cm 2 3x3 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 last 2m absorbing

14. 3) a=18m b=3cm square larger openings (1.5) 2 cm 2 3x3 cm 2 (1.5) 2 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 last 2m absorbing

15. 3) a=18m b=3cm octogonal larger openings (1.5) 2 cm 2 3x3 cm 2 (1.5) 2 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2

16. 3) a=18m b=3cm octogonal larger openings (1.5) 2 cm 2 3x3 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 last 2m absorbing

17. 3) a=18m b=3cm octogonal larger openings (1.5) 2 cm 2 3x3 cm 2 1cm 0.5° 0.4cm 2 0.7cm 2 1cm 2 last 4m absorbing

18. Conclusions and future work future comparisons (extreme environment HZB) * single ellipse vertical and double ellipse horizontal gravitation & PSC larger vertical entrance * single ellipse vertical and double ellipse horizontal - kinked * Selene Single ellipse: high BT homogeneous pos and div 2x2 cm 2 critical for choppers opening time/undesired flux reduction Double ellipse: SQUARE higher BT, spoils homogeneity pos and div OCTOGONAL high BT for 0.4x0.4 cm 2 sample size STRAIGHT central section doesn’t increase performance doesn’t destroy pos and div homogeneity RELAXING (1.5) 2 cm 2 leads to higher BT EXCHANGEABLE end of the guide to tailor divergence to exp wishes

19. Thank you for the attention