Neutrino coherent scattering in Liquid Xenon

Transcription

1 Neutrino coherent scattering in Liquid Xenon 1

2 Quasi-free electron emission from nonpolar dielectrics p z e 0 V(z) z V(z) (b) e e V o V 1 z 0 dn /dp e z V o V ( z) = V 1 0 V ( z) = ef ef z 1 z + ea + ea, z < 0 1, z > ,2 = e( ε 1 ε 2 ) / 4ε 1,2 ( z + ξz / z )( ε1 + ε 2 A [ )]

3 Probability of the quasi-free electron emission from some non-polar dielectrics K SAr LAr SXe -6 t,10 s e isooctane -1 t e, 10 4 s F LXe F, kv/cm F. kv/cm -6 t,10 s e liquid argon F, kv/cm 1/ 2 1/ 2 1/ 2 1/ 2 te ~ ( Λ / vd )exp{[ V0 2eA1 (1 + A2 / A1 ) F ]/ kbt}

4 T, K μo, cm2/v/s Vo, ev Ec, kv/cm Emitters of cold electrons Eo, kv/cm L 4 He s (100V/cm) L n-h L iso-o μs (1kV/cm ) L TMP LAr μs (100 V/cm) SNe Emitters of hot electrons LCH <4 SCH 4 77 ~ <1.5 < 0.1 μs (>1kV/cm) te LAr < 0.1 μs (>0.3kV/cm) SAr (6K) 0.1 < 0.1 μs (>100V/cm) LKr < 0.1 μs (>1.6kV/cm) SKr (20K) 0.98 < 0.1 μs (>1kV/cm) LXe < 0.1 μs (>1.8kV/cm) SXe (40K) 1.25 < 0.1 μs (>1.3kV/cm) Note: n-h normal hexane, iso-o - isooctane, TMP - thetramethylepentane

5 Wall-less emission detector Sensitive to single ionization electrons Two signals from ionization and excitation of atoms «Selfshielding» Large mass working media Bolozdynya, Egorov, Miroshnichenko, Rodionov.IEEE Trans. Nucl. Sci. v.42, n.4 (1995)

6 Real signals from XENON10 LXe emission detector

7 Separation of gamma and nuclear recoil signals Energy, kevee

8 Self-shielding

9 Coherent neutrino scattering off heavy nuclei 9

10 P. S. Barbeau, J. I. Collar, J. Miyamoto, and I. Shipsey IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 50, NO. 5, OCTOBER

11 RED-1 2x7 FEU-181, MgF 2 Болоздыня

12 Distribution of EL (S2) signals generated by single emitted electrons (green). Maximum of the Gauss fit is 15 ± 5 photoelectrons. Poisson distribution for 10 and 15 expectations are shown in pink and violet, respectively. Typical gamma event in RED-1 A.Burenkov, D.Akimov et al. Ядерная физика 72: , 2009; Phys. Atom. Nucl. 72: ,

13 Research reactor IRT MEPhI 1 RED-1 2 Fe/Al filter 3 horizontal neutron channel GEK10 4 starting point of MCNP simulations 5 cooling water pool 6 active zone 7 heavy concrete shielding 13

14 RED-1 at GEK-10 IRT MEPhI 0.5 m Zitep RED

15 Al/Fe filter

16 2 ±0.7 kev filter (g/cm 2 ) 10 B (85%) Sc 60 Ni 54 Fe S 59 Co Al ±0.96 kev filter (g/cm 2 ) 10 B (85%) S Fe Al ±2 kev filter (g/cm 2 ) 10 B (85%) Si S Al ±1.4 kev filter (g/cm 2 ) 10 B (85%) 52 Cr 58 Ni 60 Ni Si Al O.Gritsai, The 3rd International Conference Current Problems in Nuclear Physics and Atomic Energy (NPAE-Kyiv2010) 7-12 June, 2010, Kyiv, Ukraine

17 ? Fe-Al Si-Ti Si-Ti Mn-V-S Ionization yield of liquid xenon for nuclear recoils and transmission maximum of interference neutron filters marked with red arrows 17

18 Scintillation efficiency L eff Fe-Al Si-Ti Si-Ti Mn-V-S Energy, e - /kevnr Relative scintillation efficiency of LXe 18

19 RED-1 RED m HAMAMATSU R8778 Hamamatsu R m 19

20 20

21 Kalinin nuclear power plant facility dn\de, counts/kev/kg/s γbackground under the reactor γbackground in the lab Room A336 ( ) Office ( ) Energy, kev

22

23 SNS

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25 Parameters used in spectra simulations: Xe: 100 kg in fiducial volume Ar : 100 kg total mass Detector Ionization yield for gamma-rays: Xe Constant 64.1 e-/kev (15.6 ev/e-) at Е>100 kev dn e /de= E E 2 at E 100 kev 6.4 e-/kev at 5 kev 19.2 e-/kev at 15.3 kev 20.5 e-/kev at 17.3 kev 22.8 e-/kev at 21.4 kev Ar Constant 39.1 e-/kev (25.6 ev/e-) at Е>100 kev dn e /de = (15.6/25.6)E [(15.6/25.6)E] 2 at E 100 kev Ionization yield for nuclear recoils: Xe Linear from 0 to 7.8 e-/kev at E<4.0 kev dn e /de = 12.5E at 4keV E<200keV Constant 2.06 e-/kev at E>200 kev Ar Scaled from Xe with factor 15.6eV/25.6 ev

26 SNS 20 m from the target of SNS Cosmic neutron background is suppressed by factor 1000 due to duty cycle. Effect = 6000 events/year 40 m from the target of SNS SNS neutron bckgr suppressed by factor 10 9 due to ground shielding Effect =1470 events/year

27 Well-logging detector? LN Dewar for TS condensors Interface Instrumentation LUX at Homestake Vacuum & TS Lines Flexible Hoses - Communication Lines Thermo-Syphones Cryostat Liquid Xenon -100 C

28 LN Dewar Interface Ground shielding 40 m from target 10 m below ground level neutrino

29 LN Dewar Interface Cosmic muon veto Ground shielding Iron shielding 40 m from target neutrino Water shielding

30 Single electrons background Spontaneous single electron emission observed in ZEPLIN-III, Xenon-10, RED-1 SE background rate: strongly depends on potential barrier at the interface depends on intensity of radioactive background (5 Hz spontaneous rate in ZEPLIN-III, 40 Hz in RED-1) Single electron events could be suppressed by cleaning interface with tangential electric field x-y positions of single electron events in a 12 kg emission LXe detector ZEPLIN-III installed in the underground lab Santos arxiv v1

31 Conclusion Coherent Neutrino Scatter is interesting for basic science - and possibly for non-proliferation applications Emission two-phase detectors look suitable for detecting CNS Measurement of the ionization yield for nuclear recoils below ~kevr energies is a key element toward the observation of CNS Single-electron noise is a factor limiting sensitivity of LXe emission detectors