1 / 13

LENS-CAL I. Barabanov, V. Gurentsov, V. Kornoukhov Institute for Nuclear Research, Moscow and

LENS-CAL I. Barabanov, V. Gurentsov, V. Kornoukhov Institute for Nuclear Research, Moscow and R. S. Raghavan, Virginia Tech LONU-LENS Blacksburg, Oct 15, 2006. Nuclear Matrix Element for Indium Neutrino Capture Reaction. The Capture Cross Section is

efuru
Download Presentation

LENS-CAL I. Barabanov, V. Gurentsov, V. Kornoukhov Institute for Nuclear Research, Moscow and

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LENS-CAL I. Barabanov, V. Gurentsov, V. Kornoukhov Institute for Nuclear Research, Moscow and R. S. Raghavan, Virginia Tech LONU-LENS Blacksburg, Oct 15, 2006

  2. Nuclear Matrix Element for Indium Neutrino Capture Reaction The Capture Cross Section is σ = 1.632 x10-44 x [gA2 B(GT)] We pe F(ZW)] gA2 = 1.58 We Prompt Electron energy in mc2 units pe Electron momentum = √ (We2 – 1) F(Z=50, We) Fermi function B(GT) is reduced Gamow Teller Nuclear Matrix Element B(GT) must be calculated/ measured in Laboratory Theoretical Estimate made in RSR original PRL paper: Using nuclear systematics and shell model parameters of the The In (initial) and Sn (final) states: B(GT) ~ 0.16 :

  3. Measurement: J. Rapaport et al, Phys.Rev. Letters 54, 2325 (1985) Performed via 115In(p,n) forward scattering at Indiana U Cyclotron σ (p,n) is proportional to B(GT) Forward (0o) neutron emission with. Ep= 120 MeV and 200 MeV B calibrated against B(F)= 3 for Analog state Result: B(GT) (neutrino state) = 0.17 (10%) B(GT) ~0 to states upto 4 MeV V. good agreement with rsr theory In-Sn neutrino state Neutrino state

  4. Neutrino Source Calibration of B(GT) • In(p,n) reaction is strong interaction reaction which measures B(GT) via strong interactions. • Desirable to have direct weak interaction measurement of B(GT) • Direct measurement using a megCuri neutrino source. • LENS-CAL Source Technology & Expertise developed in Russia (SAGE detector calibration with 51Cr and 37 Ar Sources) LENS-CAL MegaCurie source made in Russia + Compact In loaded detector Operated probably in Baksan

  5. Table I: Characteristics of neutrino Sources for LENS-CAL Neutrino Energy typically 700 keV

  6. Source Energy ~700 keV OK for LENS-CAL First: No other excited state reached. LENS tag ensures excitation of specific state in daughter Sn. Usual problem in radiochem expts such Ga is not present here Second: Energy beyond In beta Endpoint. So double Coincidence enough Simplified tag analysis

  7. Design Concepts for LENS-Cal Detector • Indium Density • Consider a neutrino source in the center of a spherical detector • The event yield Y is: • Y= σερ{ S /(4π r2 )} k 4π r2 dr = σε kρR(= radius of detector) • -k = the fraction of 4π enclosed by the detector array (k ≤1) • ε = the signal detection efficiency  In foil thickness • Y varies as ρ the Indium Density. • Need design with high Indium density • In LS typically In is 8% -15% • Can this be increased? • In foil –Plastic Sandwich Stack Detector

  8. Basic Idea of Sandwich Stack -- Use thin Indium foil sandwiched by thin plastic bar Thicknesses: Indium foil Signal electron emerge with high efficiency Plastic thickness > range of electron Optimized thicknesses: In foil 70-100 mg/cm2 Plastic: 300 mg/cm2 Good for Eν ~700 keV

  9. In Sandwich Stack Expts Bell Labs 1979 Original Intent –pp neutrinos ! very thin In foil <10mg/cm2 plastic 160mg/cm2 ρ~60g/l Compared to Ar source: In foil 100mg and Plastic 300 mg ρ~330 g/l Sandwich stack design offers X2.2 higher Indium density Modules with Stacks 20x20x200cm Light attenuation OK Recent INR Monte Carlos Verify

  10. LENS-CAL: Conceptual Design based on Sandwich Stack In Loading Side view Plan view 60 60 60 37Ar 37Ar Ar 37 360 Indium = 8 tons Plastic 25 tons. Indium 100mg/cm2 Plastic 300mg/cm2 Indium Density ρ= 0.33 g/cm3. Plastic Module 20x20x200 max Light guides/PMT’s

  11. Preliminary Simulation Results 51Cr source with activity - 5 mCq Neutrino cross-section capture – 3.03x10-44 cm2 In thickness 0.1 g/cm2 Scintillator slab thickness 3 mm Threshold for neutrino electron – 450 keV Threshold of shower energy - 300 keV. Total In mass – 5 t Module cross section 5*5 cm2 10*10 cm2 15*15 cm2 Neutrino detection efficiency, % 31 26 22 Background (total) per day 1.5 2. 4.4 Number of neutrino events per 100 d 1515 1271 1075 Good Event Rate and Low intrinsic In Bgd.

  12. New Physics from LENS Cal? • Look for Sterile Neutrino Oscillations in LENS-CAL • L. Mikaelyan et al, hep-ph/0310246; Jonathan Link • LSND Δm2 ~1eV2 ~104 x Δm122 of reactor νe ̃ • sin2 2θ ~0.1to 0.001 • Test at short baselines <10m available in LENS-CAL • Kamland 105 m x10-4 (0.7/3 MeV) ~ 2m in LENS-CAL • Look for event rate distribution vs. radius in LENS-CAL detector ! [i] LSND Collaboration, Phys. Rev.Lett. 79 (1998) 1774 [ii]KamLand Collaboration, Phys. Rev. Lett. 94 (2005) 081801

  13. Conclusions Preliminary Analysis Shows Indium sandwich Stack Detectors with Technically feasible 51Cr sources are viable Further work for: other sources Source Strengths …. Revisit In LS modules lower density but higher efficiency

More Related