Keep the standard candle of electron observations burning Provide an intercalibration with PAMELA and AMS Search for the origin of the turn up in the low energy electron spectrum LEE Low Energy Electrons Scientific Objectives

2 For Decades the Cosmic Ray Electron “Standard Candle” Has Been LEE Time profile of helium and electron observations at a rigidity of 1.2 GV Magnetic Polarity

LEE A series of balloon observations of electrons with LEE begun in 1968 at the University of Chicago and has continued at the Bartol Research Institute since The data from these balloon flights have been used to study solar modulation of electrons with energies up to ~ 20GeV. Flight Log for LEE

LEE Schematic Drawings of the LEE. Briefly, the instrument detects electrons with plastic scintillators T1, T3 and G (anticoincidence) and the gas Cherenkov detector T2. It measures the electron energy in a cesium iodide (T4) and leadglass (T5) calorimeter. Scintillator T6 also assists in particle identification and energy determination by counting the number of particles that escape the calorimeter. 25

Schedule Support Integration System/Sub-system status Open Issues

Science Campaign Participants NameRoleArrival John ClemPIMay 8 Chris Elliot TechnicianMay 5 Paul Evenson Co-I June 1* James Roth Science campaign manager May 5 Jessica Sun EngineerMay 5 Jeff Townsend Student Jun 10*

Science Readiness LEE integration Feb

Top Scintillator Lead Glass Calorimeter The pulseheights and event rates from the LEE instrument are within norm of expected performance. Furthermore the PHA means and RMS are similar to calibration and checks from previous campaigns. Response to Ground level Radiation at Palestine During Integration Pulseheight Distributions Cherenkov Instrument Status

LOS and On-board Recorder Data taken during Integration LOS Recorder Playback

The flight shell and o-ring passed the Pressure Leak Test Test Procedure was the following: The empty Gondola shell is pressurized with nitrogen to 20psi and after 10 minutes of monitoring the shell was valved to 15psi and then re-sealed. The pressurized shell was observed for over 4 days (~110hrs). Pressure and temperature were recorded during this full period. Black curve represents the absolute internal pressure raw data while the red curve represents the measurement corrected for temperature. The procedure took placed in a sea-container and the ambient temperature was below freezing during the last few points.

12 LEE Flight Requirements Minimum exposure of 48hrs above 100kft including 10hrs above 135kft Desired exposure 30hrs exposure above 150kft Flight Profile –Remain north of 0.5 GV geomagnetic cutoff –Altitude excursions are helpful

13 LEE Work Space 25 ft x 25 ft work space ½ ton overhead lift 5 x 115V power outlets (50 amp) 60hz converters for running motors Phone line (shared with AESOP) Reliable internet service to OCC (Palestine) N2 gas bottle is needed May 6