1. Alex Howard, CERN Slide 1 Simulating Dark Matter Detectors (a.k.a. DMX Underground Advanced Example) 1.Dark Matter detectors 2.Implementation within Geant4 3.Running DMX advanced example 4.Output – AIDA and PI 5.Conclusions

2. Alex Howard, CERN Slide 2 UKDMC Experiment

3. Alex Howard, CERN Slide 3 DMX underground physics advanced example ( Dark Matter eXperiment ) Developed from Last Year’s Workshop Project

4. Alex Howard, CERN Slide 4 The DMX advanced example The Dark Matter eXample was released with Geant 4.4.0 and updated with release 4.4.1 (geometry, analysis) Gives example of Dark Matter type experiment with a scintillator target (LXe), low energy physics interactions, ray tracing of scintillation of photons and time constants introduced to demonstrate discrimination

5. Alex Howard, CERN Slide 5 User Example Class Diagram

6. Alex Howard, CERN Slide 6 DMX Class Diagram

7. Alex Howard, CERN Slide 7

8. Alex Howard, CERN Slide 8 Internal Structure To full construction:

9. Alex Howard, CERN Slide 9 Laboratory Geometry Implementation

10. Alex Howard, CERN Slide 10 Laboratory Geometry Implementation

11. Alex Howard, CERN Slide 11 detector worlddetector detailsource

12. Alex Howard, CERN Slide 12 Ray Tracing GXe LXe PMT mirror source

13. Alex Howard, CERN Slide 13 hits Evt Etot LXe LXeTime PMT PmtTime First Flags # MeV hits ns hits ns hit 0 0.0600 104 0.00057 48 35.98 gamma gamma electron 2 0.0308 121 4.8e-06 37 52.21 gamma gamma electron 3 3.9547 4538 2.7e+17 1733 19.55 alpha electron other 4 5.2674 7521 8.1e-05 11356 21.83 alpha electron other 5 0.0860 204 1.3e-3 84 16.93 Xe129[0.0] other

14. Alex Howard, CERN Slide 14 PhysicsList transportation optical electromagnetic hadronic decay user cuts: step, time “selective” scintillation low energy models neutronHP models radioactive decay

15. Alex Howard, CERN Slide 15 other features PrimGenAction RunAction analysis EventAction SteppingAction StackingAction particle gun output for analysis kill particles for speed colour tracks AIDA and PI

16. Alex Howard, CERN Slide 16 Am241 source Am241 Np237 (92.7 keV)  (59.5 keV)  (5.49 MeV)

17. Alex Howard, CERN Slide 17 upwards Xe shellPb compton through 

18. Alex Howard, CERN Slide 18 roomelastic inelasticoutside n

19. Alex Howard, CERN Slide 19 experimental 241 Am spectrum

20. Alex Howard, CERN Slide 20 experimental  spectrum

21. Alex Howard, CERN Slide 21 Time Constant Discrimination Red Curve = AlphasRed Curve = Alphas Blue Curve = GammasBlue Curve = Gammas Experimental Data Geant4 Output