2.3.0 spase://SMWG/Instrument/BARREL/1L/OpticalPhotometer BARREL 1L Optical Photometer 2021-07-20T13:41:27Z This Document describes the BARREL Balloon 1L Optical Photometer Instrument. Objective: To detect the Flux of visible Light at Wavelengths near 486.1 nm during a Relativistic Electron Precipitation Event. This will determine whether there are Protons accompanying the precipitating Electrons. Emissions near 486.1 nm are a Signature of precipitating Protons. Correlated Proton and Relativistic Electron Precipitation would support scattering by EMIC (Electromagnetic Ion Cyclotron) Waves at the Precipitation Mechanism. How it works: The Photons are collected through a Collimator Tube that restricts the Field of View to a Cone approximately 5° full-width angle, tilted at 35° from the Zenith. A 2.5 nm wide Hβ Filter is mounted near the Base of the Collimator. Each Photon incident on the 5 cm Diameter Photomultiplier Tube results in the Generation of a Charge Pulse. These Pulses then go into a charge-sensitive Pre-Amplifier, Discriminator, and Shaping Electronics, producing a TTL Pulse for each incident Photon. By counting the Number of Pulses, the Flux of the precipitating Protons can be determined. This Description is adapted from Reference #1 in the Information URL List. spase://SMWG/Person/Robyn.Millan PrincipalInvestigator spase://SMWG/Person/Robert.P.Lin CoInvestigator spase://SMWG/Person/Michael.P.McCarthy CoInvestigator spase://SMWG/Person/Mary.K.Hudson CoInvestigator spase://SMWG/Person/Mikhail.I.Panasyuk CoInvestigator spase://SMWG/Person/Lee.Frost.Bargatze MetadataContact BARREL Instrument Descriptions (Reference #1) https://doi.org/10.1007/s11214-013-9971-z Overall BARREL Instrument Descriptions for the Arctic Flight MINIS North BARREL Mission Overview Poster (Reference #2) https://barrel.rmillan.host.dartmouth.edu/ BARREL Mission Foldout Sheet Overview Poster JASTP Publication: Understanding Relativistic Electron Losses with BARREL (Reference #3) http://www.sciencedirect.com/science/article/pii/S1364682611000071 Understanding Relativistic Electron Losses with BARREL, J. Atmos. and Sol.-Terr. Phys., 73(11-12), July 2011, pages 1425-1434 by R. Millan et al. Description of Science Output from BARREL Test Flights, includes Discussion of Instruments and Usage. DOI: https://doi.org/10.1016/j.jastp.2011.01.006 BARREL Science Team Information http://www.dartmouth.edu/~barrel/team.html Site used for BARREL Science Team Information EnergeticParticleInstrument Photometer PhotomultiplierTube Balloon Array for RBSP Relativistic Electron Losses (BARREL) spase://SMWG/Observatory/BARREL/1L