26th Oct 2006CAA cross cal meeting, MSSL RAPID Calibration Status RAPID team

26th Oct 2006CAA cross cal meeting, MSSL RAPID

26th Oct 2006CAA cross cal meeting, MSSL RAPID IIMS

26th Oct 2006CAA cross cal meeting, MSSL RAPID IIMS

26th Oct 2006CAA cross cal meeting, MSSL RAPID IIMS Main IIMS calibration issues are Species identification How the TOF and energy signals are used to determine the mass of the incident ion. Events with TOF but no energy signal Detector evolution Long term evolution of the MCP Solar contamination

26th Oct 2006CAA cross cal meeting, MSSL RAPID IIMS Mass Selection Direct events used to assess on board classification. For ions above the under range threshold, classification is good for major species. For ions in the bottom channel where only TOF selection can be done the results are less reliable. The current assessment is that the lowest He energy channel is likely to have a significant level of proton contamination.

26th Oct 2006CAA cross cal meeting, MSSL Early mission data has full coverage. Due to problem with solar contamination in the equatorial detectors, MCPs in these heads lost gain very rapidly. The central head on all four instruments is now operating at very low gain. Head 3 on spacecraft 4 was non-operational between June 2003 and May 2006 due to an unexplained hardware fault. RAPID IIMS Solar Contamination

26th Oct 2006CAA cross cal meeting, MSSL RAPID IIMS Detector Performance The IIMS uses MCPs for detection of START and STOP pulses within the TOF system. As MCP age, the bias voltages are increased to counteracted the effects of reduced gain. Original MCP monitoring was done via inter-head comparison. This method has limitations and Lindau are now developing an improved technique based on the ratio of the TOF counts to the energy signal. This works well provide it is applied in suitable regions.

26th Oct 2006CAA cross cal meeting, MSSL RAPID IIMS Detector Performance Lindau have performed preliminary analysis for mission to date. The efficiency factors are being added to the latest version of the calibration files. This will provide a good basis to re-visit the cross-calibration activities with CIS.

26th Oct 2006CAA cross cal meeting, MSSL RAPID IES

26th Oct 2006CAA cross cal meeting, MSSL RAPID IES IES is an integrating sensor which means it detects the total energy deposited in the SSD within a short interval. If no event occurs within the integration interval then get a zero signal level. There is a degree of electronic noise which results in a distribution of measurements around the zero level (this is called the pedestal). The position of the zero point varies as a function of count rate and temperature.

26th Oct 2006CAA cross cal meeting, MSSL RAPID IES The instrument monitors the position of the pedestal so that shifts can be corrected on the ground. The pedestal position varies with different detectors which means that the energy thresholds vary. Spectral re-sampling is used to get all the detectors onto the same set of energy bins which is vital for construction of uniform 3D electron distributions. Due to aging or non-optimal configuration some pedestal counts may fall into the science channels. IES is susceptible to high fluxes of ions in the range keV

Pedestal contamination Pedestal channels

26th Oct 2006CAA cross cal meeting, MSSL RAPID IES Example of spectral re-sampling (provide by Jackie Davies)

Instrument configuration has recently been changed to provide better matched lower energy thresholds. This helps to avoid re-sampling artefacts with the L3DD data. BEFORE AFTER

26th Oct 2006CAA cross cal meeting, MSSL RAPID IES – Solar Contamination Solar contamination seen on one head of IES on Cluster 3 Clear dependence on solar aspect angle Patrick has negotiated with ESOC to adjust SAA to minimise this effect.

26th Oct 2006CAA cross cal meeting, MSSL C1 IES Background Levels from study by A. Aasnes, R. W. H. Friedel Low level of background noise (few counts per spin seen on all detectors on all spacecraft. Levels have been fairly stable over the lifetime of the mission. Likely to be caused by penetrating cosmic ray particles. RAPID IES – Background Levels

26th Oct 2006CAA cross cal meeting, MSSL Related statistical analysis of background by Stefan Muehlbachler shows similar results. Several options for removal of the background rate in the CAA products are under consideration. Subtraction of standard background level. This will mean that at low counts the flux may go negative. Separate data product giving the best estimate of the background level. RAPID IES – Background Levels

26th Oct 2006CAA cross cal meeting, MSSL C4 IES Background Levels from study by A. Aasnes, R. W. H. Friedel Sudden increase in Sept 2003 due to pedestal broadening resulting from radiation damage. RAPID IES – Background Levels

26th Oct 2006CAA cross cal meeting, MSSL RAPID PEACE/RAPID Cross Cal PEACE/RAPID Kappa fitting undertaken for a small number of intervals by Jackie Davies and broader analysis by A. Aasnes (see talk by M Taylor). The original study found that the fit is quite sensitive Two quite similar distributions result in significant differences in the cross cal parameter. The gap between PEACE and RAPID energy ranges hinders comparison.

26th Oct 2006CAA cross cal meeting, MSSL RAPID PEACE/RAPID Cross Cal Particular issues are: Are we comparing like with like? Most of the current tests have used PEACE SPINPAD compared to RAPID omni-directional. Should we be using the kappa fitting technique to determine the cross-cal parameters or just as a verification of the cross cal from other techinquies. Do the new PEACE inter-anode comparisons make any difference? A particular area that the RAL group is investigating is intervals where we have RAPID-IES data down to ~19 keV. These intervals are restricted to particular modes and detectors so would need comparison with PEACE 3D distributions. See Matt’s talk for more discussion on this…