1. LENS:  LENS Simulations, Analysis, and Results B. Charles Rasco Louisiana State University on behalf of the LENS Collaboration

2. Why Low-Energy Neutrino Spectroscopy (LENS)? Compare the photon luminosity of the sun to the luminosity of pp and CNO energy output from the sun. Measure the CNO in order to get a direct measure of the metalicity of the sun. To get e energy information from the sun!

3. Why LENS? 497 keV 115 keV What signal are we looking for? E e = E -Q E (See R. Bruce Vogelaar’s Presentation J9-5) e + 115 In  115 Sn* +   Use 115 In because reaction has a low Q value (~115 keV) In-loaded (~8% - 10 tons of Indium) liquid scintillator (LAB) In order to identify the electrons and gammas above background good position and time resolution are required. One way to accomplish position resolution is with a 3D segmented detector such as a scintillation lattice detector. LENS is a 60x60x60 scintillation lattice detector. Phys. Rev. Lett. 37, 259 (1976).

4. What is a Scintillation Lattice? Thin Container Filled with Liquid Scintillator Container Index of Refraction = n 1 (Could be air) Liquid Scintillator Index of Refraction = n 2 > n 1

5. What is a Scintillation Lattice? (Though this animation just shows a Scintillation Plane) We call this a Scintillation Lattice

6. What Is LENS? (See Z. Yokley’s Presentation - J9-6)

7.  LENS - 6x6x6 – 3” Cubes – Now miniLENS - 9x9x9 – 3” Cubes – Under Construction LENS –  LENS and miniLENS will show the way... 4 m Water Tank  LENS and miniLENS (See D. Rountree’s Presentation J9-7)

8. What Was Measured? ~.5  Ci 137 Cs Source Located Near Center Bottom of  LENS for ~ 1 hour Background Run for ~ 1/2 hour Longer Background Run for ~ 1 week ~.5  Ci 137 Cs Source All Runs Triggered on Center Four Top PMT Trigger PMT Y=2 Plane Y=3 Plane Y=4 Plane Y=5 Plane PMT All Approximately Normalized by Previous Measurements

9. Background Subtracted 137 Cs Data Raw 137 Cs Source (662 keV  ) Background Subtracted 137 Cs Source Background Normalized Over This Region 40 K (1460 keV  ) (Compton Edge or Full E Deposit?) Thorium (2.6 MeV  ) (Compton Edge or Full E Deposit?) Low E Bump 137 Cs (Compton Edge or Full E Deposit?)

10. Simulation of 137 Cs Source at Bottom of  LENS Relative height of low energy bump to high energy bump depends on the trigger level. Low Trigger Threshold Medium Trigger Threshold High Trigger Threshold

11. Simulation of 137 Cs Source at Bottom of  LENS Low Trigger Threshold Low Energy Peak is a Low Energy Deposit in the Plane. Most Likely Several Mostly Forward Compton Interactions (The Most Probable to Happen) in a Single Cell as the  Crosses the Plane. High Energy Peak is a Mixture of the Full Energy Deposit, Full Energy Minus Loss in the Outer Acrylic Shell, and the Compton Edge Deposit in the Plane.

12. High Trigger Comparison of Simulation and First 137 Cs Measurements Background Subtracted 137 Cs Simulated 137 Cs Measured data is proportionally normalized, not linearly normalized. Simulated Number of PE / Proportionally Scaled Channel Number

13. VT -- R. Bruce Vogelaar, Mark Pitt, Camillo Mariani, S. Derek Rountree, Laszlo Papp, Tristan Wright, Joey Heimburger, Lillie Robinson, Zach Yokley LSU -- Jeff Blackmon, B. Charles Rasco, Liudmyla Afanasieva, Kevin Macon, Matt Amrit BNL -- Minfang Yeh BNL NCCU -- Diane Markoff UNC -- Art Champagne The LENS Collaboration

14. BACKUP SLIDES

15. Prediction for 3 Plane  LENS with Low Trigger Measurement with Low Trigger Threshold And What it Translates to Measuring Sum Y=2+3+4 Planes Sum Y=2 Plane Sum Y=3 Plane Sum Y=4 Plane

16. Prediction for 3 Plane  LENS with High Trigger Measurement with High Trigger Threshold And What it Translates to Measuring Sum Y=2+3+4 Planes Sum Y=2 Plane Sum Y=3 Plane Sum Y=4 Plane