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SYSTEMATICS (preliminary consideration)

SYSTEMATICS (preliminary consideration). V. Sinev for Kurchatov Institute Neutrino group. Common consideration. If the detectors, far and near, are absolutely identical, the ratio of two measured positron spectra S far and S near is energy independent:

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SYSTEMATICS (preliminary consideration)

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  1. SYSTEMATICS (preliminary consideration) V. Sinev for Kurchatov Institute Neutrino group

  2. Common consideration If the detectors, far and near, are absolutely identical, the ratio of two measured positron spectra Sfar and Snear is energy independent: SFar/SNear = 1 inno-oscillation case,   normalization: equal number of events Detector differences can mimic or hide oscillations Following deviations from detectors identity have been studied: • Different energy resolutions Far, Near • Different edge effects (positron annihilation quanta escape) due to different detector volumes VFar and VNear.   • Different light collection due to difference in the light absorption lengths (440 nm)

  3. Sfar/Snear for different energy resolutions Expected ratio for sin22q13=0.02, Dm2 = 2.510-3 eV2 Positron visible energy, MeV

  4. Sfar/Snear versus Detector volume ratio Vfar/Vnear Expected ratio for sin22q13=0.02, Dm2 = 2.510-3 eV2 V1=1.2V2 V1=1.15V2 V1=1.1V2 Positron visible energy, MeV

  5. Light collection vs source position r and light attenuation length l (440 nm) Transparency Light collection from the centre Light source position, m

  6. Sfar/Snear for different attenuation lengths lfar, lnear Expected ratio for sin22q13=0.02, Dm2 = 2.510-3 eV2 Positron visible energy, MeV

  7. Neutron detection efficiency vs neutron capture point Distance from the centre, m

  8. Two gammas absorbed energy versus the point of positron annihilation Distance from the centre, m

  9. OTHER OPTIONS The Kr2Det scheme with two ~ 50 ton detectors at ~100 and 1000 meters uses available underground rooms and does not require digging new special caverns. The oscillation signal could be increased  (1) with the far detector at about 1500 m and (2) in a 3 detector scheme:   one near and two far detectors at ~1400 and ~ 2700 m. This increase will require larger volume detectors, deeper detector positions and digging new under-ground halls.

  10. Sfar/Snear at different detector positions Dm2 = 2.510-3 eV2 1.01 1 0.99 1000/100 1.01 1 0.99 1900/100 0 1 2 3 4 5 6 7 8 Visible energy, MeV

  11. 1.01 1 0.99 1600/900 900/100 1600/100 1.01 1 0.99 2600/1300 1300/100 2600/100 1.01 1 0.99 3600/1800 3600/100 1800/100 0 1 2 3 4 5 6 7 8 Visible energy, MeV

  12. Possible experimental result for ratio at Krasnoyarsk

  13. Conclusion We estimated some effects which can influence the ratio to mimic effect of oscillation Kr2Det usesavailable underground halls for far (1000m) and near (115m) 50-ton detectors The oscillation signal could be somewhat increased with the Far detector at ~ 1400-1900 m or with two far detectors at ~ 1300 and 2600 m… This however would require digging new caverns and using detectors of larger target masses…

  14. Letter of IntentionI.R.Barabanov, L.B.Bezrukov, V.I.Gurentsov,V.N.Kornoukhov, E.A.YanovichInstitute for Nuclear Research of RAS(Moscow, Russia)N.A.Danilov, G.V.Korpusov, Yu.S.KrylovInstitute of Physical Chemistry of RAS(Moscow, Russia) Development of a recipe and production of components for a liquid scintillator doped with Gd for K2Det or Kashiwazaki experiment.

  15. 1. Development of test batches of Gd-compound for a liquid scintillator. Based on experience in the framework of LENS Collaboration on the development of Yb-loaded scintillator with characteristics: LY = 60% of BC 505; (8% of Yb), L1/2 (430 nm) ~ 2.5 m (8% of Yb), ^ when c dec. we propose to develop and synthesized Gd-loaded LS replacing in our Yb-Carboxylate compound Yb by Gd because of their common chemical properties (even more difficult for Yb). M ~ 2 x 150 kg (0,3% of Gd) The procedure is just simple blending “Gd-compound + solvent”. 2. Production, purification and certifi-cation of an effective primary fluorescent additive (fluor) BPO, 2[4-biphenyl]5-phenyl oxazole. Light Yield of BPO is ~ 50% more than LY of PPO. M = ~ 2 x 100 kg Development of new fluor with maximum emission in 430-440 nm

  16. 3. Delivery of organic base (a solvent) for LS with a high flash point (~ 80oC). • M ~ 100 t • Light output 80% of Whitespirit • Composition H/C ~1.8 • Transparency >10 m • Radio purity is low but should be investigated • Chemical activity - weak • If LS has H:C ~ 2 (for example, Palo • Verde and CHOOZ experiment): • Then for Gd = 0% (100% captured • probabilities with E = 2.2 MeV): •  = 180 sec • for Gd = 0.1% (86% captured probabilities with E ~ 8 MeV, well above the natural radioactivity): •  = 32  2% sec

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