1. Copyright © 2013 SCKCEN Pb-Bi target for ISOL@MYRRHA: Optimization toward higher yields SCKCEN Mentor : Dr. Lucia-Ana Popescu University Promoter : Prof. Jan Vierendeels Donald HOUNGBO SCKCEN, UGENT dhoungbo@sckcen.be

2. Copyright © 2013 SCKCEN IV III II I I Context, Previously presented Yield Optimization Calculations Outline LIEBE project: Status 2 Thermo-mechanical loads: Estimation

3. Copyright © 2013 SCKCEN Context ISOL@MYRRHA --> High power (60 – 120 kW) 3 Pb-Bi target investigated within LIEBE Proposed in EURISOL DS Previously presented at BriX Optimization of Hydrodynamics => Fast, Complete and Uniform evacuation of irradiated Pb-Bi for these concepts

4. Copyright © 2013 SCKCEN IV III II I I Context, Previously presented Yield Optimization Calculations Outline LIEBE project: Status 4 Thermo-mechanical loads: Estimation

5. Copyright © 2013 SCKCEN Yield Optimization 5 Release volume

6. Copyright © 2013 SCKCEN Yield Optimization : Model 6 Evacuation Diffusion Effusion Comprehensive Analytical Release Model

7. Copyright © 2013 SCKCEN Evacuation & Diffusion of Hg Time [s]Ratio of evacuated to produced 177 Hg per unit time [s -1 ] Time [s] Diffused Hg isotopes as a ratio of initial Hg content per unit time [s -1 ] Evacuation Diffusion

8. Copyright © 2013 SCKCEN Yield Optimization: Evacuation & Diffusion of Hg 8 Time [s] Evacuation & Diffusion Probability Density Function [Fraction / s] 177Hg (T1/2= 118 ms)  19 % efficiency for 12 cm height

9. Copyright © 2013 SCKCEN Yield Optimization: Effusion of Hg MPP = 17178.4 cm ̴30 000 collisions MFP = 0.624138 cm Percentage of desorbed isotopes arriving at transfer tube per bins of 1-ms Release Volume Feeder volume Irradiation volume Assuming all isotopes desorb at the same time Desorption actually spread over time (assuming 100 ms) 9

10. Copyright © 2013 SCKCEN Yield Optimization: Release efficiency Overall delay time distribution [Fraction / s] Overall Fractional Release 10 Time [s] Accounting for decay Evacuation and Diffusion Effusion 0.1 0.25

11. Copyright © 2013 SCKCEN Yield Optimization: Diff. chamb. length, 177 Hg 11 Diffusion Chamber Length (cm)5101520253035 Release efficiency (177Hg) 5.78 % 3.55 % 2.58 % 2.02 % 1.65 % 1.42 % 1.19 % Average overall delay time (s)0.390.650.891.121.401.541.84 Release Volume Feeder volume Irradiation volume 20 cm 2 cm 12 cm 1.4 GeV, 10 13 prot.

12. Copyright © 2013 SCKCEN Yield Optimization: Distrib. of Hg isotopes 12 Hg isotopes created along the beam line as a percentage of the total production

13. Copyright © 2013 SCKCEN Yield Optimization: Target length, 178 Hg Irradiation Chamber Length [cm] 178 Hg production in the Irrad. vol. 13 Release efficiency: 178 Hg Diffusion Chamber Length [cm] 178 Hg yields at transfer line

14. Copyright © 2013 SCKCEN Yield Optimization: Target length, 177 Hg 2 cm 12 cm 20 cm Release Volume 1.4 GeV, 10 13 prot. Feeder volume Irradiation volume Irradiation Chamber Length [cm] 178 Hg production in the Irrad. vol. 14 Release efficiency: 177 Hg Diffusion Chamber Length [cm] 177 Hg yields at transfer line, assuming similar production as for 178 Hg

15. Copyright © 2013 SCKCEN Yield Optimization: Diff. Chamb. Height 15 2 cm 12 cm 20 cm Release Volume Feeder volume Irradiation volume

16. Copyright © 2013 SCKCEN Yield Optimization: Droplet Radii 16 2 cm 12 cm 20 cm Release Volume Feeder volume Irradiation volume Overall delay time distribution [a.u.] Time [s] 100 μm radii 3.67% Release efficiency 1.22 s Average overall delay time 200 μm radii 2.02% Release efficiency 1.12 s Average overall delay time 150 μm radii 2.65% Release efficiency 1.17 s Average overall delay time

17. Copyright © 2013 SCKCEN Summary & Outlook Summary Comprehensive release model, Model is analytical but supported by detailed Monte Carlo Optimum target length is isotope dependent and ≤ 20 cm for short lived Hg Optimum diffusion chamber height is isotope dependent and ≤ 5 cm for short lived Hg Optimum droplets radii is below 100 μm Outlook Effusion calculations still to account for: Presence of a jet at aperture tip Distribution of in-target production Non-uniform vertical droplets distribution due to gravity Non-uniform distribution of droplets concentration in Hg due to diffusion 2 cm 12 cm 20 cm Release Volume Feeder volume Irradiation volume

18. Copyright © 2013 SCKCEN IV III II I I Context, Previously presented Yield Optimization Calculations Outline LIEBE project: Status 18 Thermo-mechanical loads: Estimation

19. Copyright © 2013 SCKCEN Thermo-mechanical loads: Estimation 200 ns (1 st bunch) ≤ 2.45 10 8 Pa≤ 3.5 10 8 Pa≤ 3.6 10 8 Pa ≤ 1.1 10 8 Pa 16.4 μs (2 nd bunch) ≤ 1.3 10 8 Pa 32.6 μs (3 rd bunch) Time Peak pressure inside liquid Pb-Bi ≤ 8.5 10 7 Pa Heat Deposition GeV/cm 3.p 200ns proton bunches 16μs bunch spacing 2.4 10 13 protons Time Intensity 200 ns 16.4 μs32.6 μs

20. Copyright © 2013 SCKCEN IV III II I I Context, Previously presented Yield Optimization Calculations Outline LIEBE project: Status 20 Thermo-mechanical loads: Estimation

21. Copyright © 2013 SCKCEN LIEBE project: Status LIEBE project subject to review by Panel of experts in June 2014 Recommendations from the panel of experts received and integrated Calculation of structural stresses & deformations due to pressure waves Offline prototype foreseen for this summer Online tests 2016 Grids tested, Shower obtained for spacing up to 0.5mm Apertures diameter of 0.1 mm. Designed at CERN and manufactured

22. Copyright © 2013 SCKCEN Thank you for your attention Questions

23. Copyright © 2013 SCKCEN Copyright © 2013 - SCK  CEN PLEASE NOTE! This presentation contains data, information and formats for dedicated use ONLY and may not be copied, distributed or cited without the explicit permission of the SCKCEN. If this has been obtained, please reference it as a “personal communication. By courtesy of SCKCEN”. SCKCEN Studiecentrum voor Kernenergie Centre d'Etude de l'Energie Nucléaire Belgian Nuclear Research Centre Stichting van Openbaar Nut Fondation d'Utilité Publique Foundation of Public Utility Registered Office: Avenue Herrmann-Debrouxlaan 40 – BE-1160 BRUSSELS Operational Office: Boeretang 200 – BE-2400 MOL