Strofio Calibration & Lunar ENAs measured by IBEX

1. Strofio Calibration &Lunar ENAs measured by IBEX Frédéric Allegrini Southwest Research Institute fallegrini@swri.org (210) 522-6029

2. Parameter space 2 angles: elevation, azimuth Energy (velocity) Neutral/ion 30 voltages Constraint Limited calibration time Overview

3. Key measurements • Voltages needed • Sensitivity: > 0.1 (counts/s)/(particles/cm3) for H2O (corresponds to 0.1A/torr ion yield and 6% transmission) [ERD_1049] • Mass resolution: m/∆m ≥ 60 [ERD_1035] • Mass range: H (1 amu) through Fe (56 amu) [ERD_1028,ERD_1030] • FOV ±10°, KOZ ±20° [ERD_1061,ERD_1059] • Velocity filter: Energy range: 0-10 eV [ERD_1784,ERD_1785] • Additional measurements: • UV attenuation and light leaks [SEN_614 , SEN_615 ] • MCP Background noise • Maximum rate of 104cts/s [ERD_ 1066]

4. Strofio Calibration Field of view (part 1)

5. Field-Of-View & Keep-Out-Zone KOZ FOV

6. Casymir(Calibration System for the Mass Spectrometer Instrument ROSINA) • Beam line • Pressure ~10-9 mbar with beam • Species: Ar, Ne, H2, He, N2, … • Velocities 1-3 km/s • Size 2-10 mm dia • Strofio dedicated chamber • Pressure ~10-10 mbar • LN2 cold plate • Up to 80°C heating system • X and Z movement via external table system • ε rotation via manual actuator • Measurement ready after 2 days of pumping

7. Geometrical Characteristics Beam • Determined by mechanical scanning the instrument: • X with table • ε with internal mechanism • Z with table (in-out of the page) ε x Z ○

8. Field of View – No Velocity Filter

9. Strofio Calibration Field of view (part 2)

10. Epsilon Scan under Large Background Rejection • Determines the geometry response of the sensor • Very irregular “two horns” shape Z [mm] Ar/H2O Ar/Max(Ar) Epsilon [deg] S1A-S1B [V]

11. Simulations vs measurements Simulations Measurements Z [mm] Z [mm] Epsilon [deg] Epsilon [deg] Testing with Strofio’s “little sister” planned for summer 2013

12. Strofio Calibration Uv contamination

13. UV leak test • First test performed at SwRI • ~1 solar intensity near Lyman alpha • UV leak(s) created signal slightly above background levels • Need to perform additional tests in Bern

14. Tests in Bern Start left rate [Hz] • Illumination of the sensor over almost the whole sphere. Data points at 1 minute integration • Reported here the two scans that raised previously some questions • Intensity = 1 sun in Lyman alpha • No sensitivity detected at the 1 cts/second level • UV through Strofio aperture also tested Start right rate [Hz] Start left rate [Hz] Start right rate [Hz]