Status of CIS Calibration Work Iannis Dandouras and the CIS Team presented by: Harri Laakso 3 rd CAA Cross-Calibration Meeting MSSL, October 2006

1. CODIF (CIS-1) Calibration Files Updating The CODIF calibrations updating is a complex process. It involves :  the determination of the start-MCP efficiency  the stop-MCP efficiency  the fraction of coincidences between the “start” and the “stop” signal that also have a single position signal, allowing thus to calculate the total efficiency [Lynn Kistler]

CODIF Calibration Files Updating (cont.) In addition, the efficiencies of the individual anodes (for each 22.5° sector) have to be cross-calibrated, and this is performed by using time periods when the ion distributions are expected to be gyrotropic. CODIF calibrations involve also separate efficiencies determination for the four main ion species. The CODIF H + measurements are finally cross-checked with the HIA measurements, for periods when the plasma is composed mainly from H + ions, and neither instrument saturates or has low counting statistics. HIA is cross-calibrated wrt WHISPER.

CODIF Calibration Files Updating : status  Complete updated CODIF calibration values set, for the High- Sensitivity side, covering the period :  from launch to Oct 2004 (sc1, sc3)  from launch to Jul 2005 (sc4) was delivered last week by Lynn Kistler and Chris Mouikis (UNH) to CESR.  Now under test and format editing, at CESR, for insertion in the reference CIS calibration files.  Work in progress at UNH for updating the calibration values for the Low-Sensitivity side.

CODIF Efficiencies for sc3 and sc4

CODIF Relative Anode Efficiencies : sc4

2. HIA (CIS-2) Energy Tables Update Previously used HIA energy tables had always E min i = E max i+1, where E min and E max are minimum and maximum energy values for particles detected at energy step i. This results in  E for each enery step (energy width) being defined by the spacing of two consecutive energy steps. For magnetospheric modes, where the electrostatic analyser energy sweep is defined in such a way as to give a spacing between two consecutive steps equal to to the analyser intrinsic  E/E this is OK. E t i i+1

HIA (CIS-2) Energy Tables Update (cont.) However, for solar wind modes the relative spacing of two consecutive energy steps, at the middle of the sweep, is closer than the analyser intrinsic  E/E (solar wind beam tracking), whereas for the steps close to the two edges of the sweep the relative spacing of two consecutive steps is wider than the analyser intrinsic  E/E. E t

HIA (CIS-2) Energy Tables Update (cont.) The HIA energy tables have thus been redefined (performed early October):  If the spacing is closer than the analyser intrinsic  E/E, then E min i = E max i+1, which is defined as the average value between the two consecutive steps energy boundaries. Although this results in energy widths, for these steps, that are smaller than the analyser intrinsic  E/E, it results in more accurate density calculations (no overlap).  If the spacing is wider than the analyser intrinsic  E/E, then the analyser intrinsic  E/E is taken to define the energy width of these steps (E min i > E max i+1 ). E t

3. Software development for moments calculation Continuation of the development of a software module (one for CODIF and one for HIA), allowing the CAA user to interactively calculate partial (or total) moments of the ion distributions, for selected energy and solid angle ranges. Software in C. Input: CIS CEF Level-3 files Output: CEF files. This is much more flexible and powerful than pre-calculated moments from 3D ion distributions, which then become redundant. However, to allow “easy availability”, CODIF pre-calculated total moments will be also provided. Parts of the software currently under test.

The CIS Experiment CODIF (CIS-1) Ion Composition and Distribution Function Analyser 3D ion distributions with mass-per- charge composition determination ~0 – 40 keV/e Energy Range Includes also an RPA: ~ eV/e (wrt spacecraft potential) HIA (CIS-2) Hot Ion Analyser 3D ion distributions with high angular resolution 5 eV/e – 32 keV/e Energy Range