1. Seoul National University Han-wool Ju CUNPA Kick-off Meeting Aug.22-23, 2013

2. Directional effects for ion penetration in crystal Channeling Effect : If an incident ion is along the symmetry axis or planes of the crystal, it will have a series of small-angle scatterings which will maintain it in the open channels. The ion will penetrate much further into the crystal than in other directions.

3. Directional effects for ion penetration in crystal Blocking Effect : If an ion originated in the lattice sites is along the symmetry axis or planes, the ion experience large angle scattering and there is a reduction in the flux of the ion when it exits from the crystal, with creating a “blocking dip”.

4. DAMA claimed that our PSD method removes some WIMP signals from channeling effect Dr. Ju-hee Lee`s channeling effect experiment Blocking effect is expected rather than channeling effect in her experimental setup In this time, researched blocking effect → Main purpose of this experiment : Affection on scintillation yield by Blocking effect Fraction of Blocking event

5. 110 axis Θ = 60° Neutron Detector Neutron Generator Polyethylene box Θ = 60° d = 50 (cm) Lead blocks Neutron Beam line Small window for Neutron Beam line (Side View)

7. (Upper View) Ф = 25° Ф = 20° ND2 ND3 ND1 CsI(Tl) crystal and PMTs at both side Calculate scintillation energy E from charge sum recorded by PMTs E = Ech E = Enon2 E = Enon1 Coincidence between PMTs and ND2 ND3 ND1

8. Switch up : Normal Switch down : Inverse Linear Fan in/out IN OUT NIM Module VME Module FADC Trigger IN Trigger OUT

9. IN OUT Signals from Neutron Detectors Signals from PMTs at each side of CsI(Tl) more than two pulses in each PMT or a large peak of over 300 ns width in a PMT for CsI(Tl) detector single pulse larger than 40 mV and over 10 ns of the pulse width, convert a TTL signal to an analog signal in the inverse mode Signals are gathered in 2 μs window

10. NameExample (1)Fit Quality(FQ) cutFQ < 2.5 (2)Second time(t1) cutdet0.t1 > 2.5 (3)Start time difference cut pmt30.t0 – det0.t0 < 0.1 (det0.Eqc≤5) -0.1 5) (4)Single hit cutOnly 1 detector has the signal When all cuts are satisfied, the events are accepted as a candidates of nuclear recoils. After that, PSD cut is applied to discriminate events as Surface Alpha, neutron and gamma induced ones.

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19. 19 Thick solid line : Present experiment Shaded area : Previous experiment

20. 20 Thick solid line : Present experiment Shaded area : Previous experiment

21. 21 Thick solid line : Present experiment Shaded area : Previous experiment

22. 22 Thick solid line : Present experiment Shaded area : Geant4 Simulation

23. 23 Thick solid line : Present experiment Shaded area : Geant4 Simulation

24. 24 Thick solid line : Present experiment Shaded area : Geant4 Simulation

25. 25 Thick solid line : Present experiment Shaded area : Marlowe Simulation

26. 26 Thick solid line : Present experiment Shaded area : Marlowe Simulation

27. 27 Thick solid line : Present experiment Shaded area : Marlowe Simulation

28. Present experiment Previous experiment MARLOWE Simulation Geant4 Simulation Ech 1.454 ± 0.0391.606 ± 0.0591.745 ± 0.0101.805 ± 0.046 σ 0.371 ± 0.0530.318 ± 0.0420.380 ± 0.0150586 ± 0.037 Enon1 1.634 ± 0.0451.815 ± 0.0651.872 ± 0.0151.830 ± 0.050 σ 0.542 ± 0.0450.546 ± 0.0510.472 ± 0.0290.669 ± 0.046 Enon2 1.649 ± 0.0391.787 ± 0.0521.853 ± 0.0111.811 ± 0.039 σ 0.559 ± 0.0420.506 ± 0.0450.449 ± 0.0170.592 ± 0.030

29. 29 Thick solid line : Present experiment Shaded area : Previous experiment rmt10 : means charge weighted mean decay time for clusters within 10 μ s

30. 30 Thick solid line : Present experiment Shaded area : Previous experiment

31. 31 Thick solid line : Present experiment Shaded area : Previous experiment

32. Present experimentPrevious experiment Energy range 0 to 6 keV0 to 100 keV0 to 6 keV0 to 100 keV Ech Mean 1.397 ± 0.0451.429 ± 0.0461.275 ± 0.0461.308 ± 0.046 σ 0.472 ± 0.0370.531 ± 0.0580.541 ± 0.0390.559 ± 0.039 Enon1 Mean 1.349 ± 0.0491.447 ± 0.0561.310 ± 0.0541.349 ± 0.064 σ 0.531 ± 0.0530.637 ± 0.0650.564 ± 0.0510.644 ± 0.070 Enon2 Mean 1.337 ± 0.0401.399 ± 0.0341.310 ± 0.0601.345 ± 0.080 σ 0.539 ± 0.0400.552 ± 0.0330.587 ± 0.0540.735 ± 0.100

33. Ech shows lower mean value than others about 10 % No significant difference in mean decay time Need more study with more statistics

35. Solid Line : 0314 ~0320, 0328~ 0610 Filled with Black : 0328~0610 Filled with Red : 0531 ~0610

36. MARLOWE computer simulation program for atomic collisions in crystalline solids with the impulse approximation open source code program written in FORTRAN

37. Geant4 (for GEometry ANd Tracking) Simulation of the passage of particles through matter Use Monte Carlo methods Application areas include high energy physics and nuclear experiments, medical, accelerator and space physics studies.