TUNL R. B. Vogelaar March 1, 2007 Measuring the complete Solar neutrino spectrum E th =114 keV (95% of pp spectrum) Measure pp- 3% Determine CNO-fraction Measure T sun by change in mean energy of 7 Be line – maybe (hep-ph/ ) needs separate calibration experiment –”LENS Sterile” LENS complementary use: sterile neutrinos

TUNL R. B. Vogelaar March 1, 2007 Apply cut algorithm pp background x cascade signal keep ~50% pp 7 Be In(   ) 7 Be * pep 15 N 15 O LENS Solar Neutrino Spectrum tt E e1

TUNL R. B. Vogelaar March 1, 2007 mini-LENS project goals establish readiness of LENS to community scale-up production of In loaded scintillator implement scintillation lattice technology demonstrate In background suppression see cosmic pp proxy events measure Q-value of In beta decay optimize scale-up route to LENS broaden collaboration

TUNL R. B. Vogelaar March 1, 2007 mini-LENS concept

TUNL R. B. Vogelaar March 1, 2007

Electronics computer 200 ns read per event threshold discriminator 0 ns 40 ns 80 ns 120 ns x10 high voltage transient digitizer (2 ns, 8 bit) trigger (2.5 kHz In) 150    3 3  1 PMTs quad fan in/out

TUNL R. B. Vogelaar March 1, 2007 Scintillator Current Status with PC 1. Indium concentration ~8%wt (higher may be viable) 2. Scintillation signal efficiency (working value): 9000 h /MeV 3. Transparency at 430 nm: L(1/e) (working value): 10m 4. Chemical and Optical Stability: at least 1 year 5. InLS Chemistry - Robust Work in Progress 1.Linear Alkylbenzene (LAB) 2.Lower cost 3.Safer 4.Better chemical compatibility 5.Good optical properties …so far: ~70% of light obtained with PC (with In)

TUNL R. B. Vogelaar March 1, 2007 Lattice Structure Single Foil Double Foil Solid teflon segmentation Double-layer (air-gap) lattice

TUNL R. B. Vogelaar March 1, 2007 Segmentation Options Foils: 1)Various Teflons 2)Acrylic 3) PET Solid: 1)Solid scintillating plastic cubes (for outer region) 2)Hollow scintillating plastic cubes

TUNL R. B. Vogelaar March 1, 2007 Surface and Underground Operation (Homestake? or Kimballton) ‘Proxy Events’ surface 1400mwe

TUNL R. B. Vogelaar March 1, 2007 Goals for 2007 Project Integration –Virginia Tech and TUNL Electronics and Trigger Design –TUNL Scintillator Preparation and Fluid Handling –Brookhaven Lattice Fabrication –Virginia Tech Monte Carlo and Advanced Electronics –Oak Ridge

TUNL R. B. Vogelaar March 1, 2007 DUSEL Context Solar Neutrinos highlighted in S1 report Solar Neutrinos identified in NSAC LRP LENS in first ‘suite of experiments’ at –Homestake –Henderson –Soudan –Cascades mini-LENS proposal submitted to NSF and DOE (as part of DUSEL R&D solicitation)