Cassini Calibration
A controlled access laboratory for post launch calibration, characterization, and diagnostics of the Cassini Plasma Spectrometer (CAPS) and the Cassini Ion & Neutral Mass Spectrometer (INMS).
Cassini Plasma Spectrometer (CAPS) Chamber
CAPS Chamber Features:
- Chamber door opens greater than 90 degrees.
- Interior tray drawer permits supported extraction of CAPS instrument & insertion of instruments up to approximately 16” x 16” x 16” cube
- Up to three lab benches available for conversion to ESD operations if necessary.
- Main chamber dimensions: 24” diameter x 24” deep cylinder
- System pumping: 450l/s Seiko Seiki magnetically-levitated turbomolecular pump backed by an scroll pump (no oil containing pumps used in the lab)
- Additional bottom flange port for second turbopump or cryopump
- 8” CF viewport
- 10” CF multi-pin instrument electrical feedthrough flange
- Numerous available flanges at an assortment of chamber positions for electrical or vacuum feedthroughs
- High purity nitrogen available for instrument purging
- Chamber vented with high purity nitrogen
- Chamber pressure, temperature, and CAPS instrument conditions monitored remotely
- Routine base pressures of 1 x 10-7 Torr
- Reaches high vacuum (turbo starts) in 10 minutes
- No thermal control
- No TQCM, No RGA
INMS Chamber Features:
- 16” x 16” stainless steel cylindrical chamber
- Three (3) 8” CF ports, two (2) 10” CF port, one (1) 13.25” CF port, and ten (14) 2.75” CF ports
- Axis of target flange (13.25” CF), all three (3) 8” CF flanges and two (2) 2.75” CF flanges occupy same horizontal plane
- Axis of target flange (13.25” CF), two (2) 10” CF flanges and one (1) 8” CF flanges occupy same vertical plane
- All metal sealed flanges and fittings
- Ceramic insulators and isolation
- NO ELASTOMERS
- Nominal base vacuum level 3 x 10-10 Torr after 200C bakeout
- INMS instrument bakeable to 250C
- Chamber bakeable to 400C, but limited to program, mission, science instrument, ion gun and turbopump temperature considerations
Cassini Ion & Neutral Mass Spectrometer Calibration Chamber
INMS Schematics
INMS Chamber Features (cont):
- INMS gimbal motion control (+/- 10 degrees in any plane)
- Scriptable movement, ion gun and instrument control
- Instruments or detectors up to 13.25” CF size
- Automated chamber parameter control, monitoring and recording
- Hardware and software overpressure failsafe protection mechanisms for system and mission critical flight hardware
- PC-controlled HV power supplies for up to 30 ion lens elements
- Four (4) automated filament emission regulator power supplies for operating up to four (4) ionization sources
- Flight-qualified RF power supply for quadrupole rod operation
- Two (2) Granville-Phillips Stabil-Ion® gauges for pressure measurement and vacuum interlock operation from 1×10-4 to 1×10-10 Torr range
- MKS spinning rotor gauge transfer standard for precise NIST-traceable pressure measurements from 1×10-2 to 1×10-7 Torr operation
- Two (2) Granville-Phillips Convectron® gauge for turbopump foreline monitoring and main chamber during venting and initial evacuation
- Pfeiffer PrismaPlus quadrupole mass spectrometer (QMS) residual gas analyzer (RGS)
- No TQCM
- No clean room or tent
- < 1 hour to reach 1×10-6 Torr, 3×10-10 Torr typical after bakeout
Ion Source
- Nominally supplies 5 ion species H+, Ar+, Ne+, He+, N+ and ion species relevant to Cassini mission, but other species possible
- Ion energies from 1 keV down to < 10 eV
- MCP imaging detection system
- Faraday cup detection and beam monitoring system
- Ion optics for beam spreading at target
- Internal ion apertures for beam diagnostics and focusing
- SwRI-developed custom ion source
- Drift tubes for conducting ions to target at low eV
- Ion source-to-target distance: ~30”
Cassin INMS Calibration System Ion Gun
Sample INMS mass scan
Graphical User Interface (GUI) for ion gun operation
Materials prohibited in both ion gun and main chamber: nylon, silicone, PVC, low molecular weight hydrocarbons, zinc, cadmium, brass, particulate contaminated or producing items/mechanisms (blacklight inspection prior to chamber entry preferred).
Image Gallery
Cassini Calibration
Cassin Ion and Neutral Mass Spectrometer Calibration Chamber
Chamber Mechanical Drawing
Cassin INMS Calibration System Ion Gun
Sample INMS mass scan