STAFF-SC / FGM Comparison I. Spectrograms comparison II. Average spectra comparison III. Wave Forms comparison IV. Noise Level Conclusions Cross_Calibration Workshop ESTEC, Noordwijk, 2-3 february 2006 P. Robert, CETP A. Reminder on old comparisons (IC, London, February 2001) B. New comparisons

P. Robert, Croos Cal WS, , ESTEC A. Old comparisons (IC, London, February 2001) Original FGM High res. Files provided by M. Dunlop Already STFF-FGM difference on perp. DC field A.1 Spectrogram

P. Robert, Croos Cal WS, , ESTEC A. Old comparisons (IC, London, February 2001) Original FGM High res. Files provided by M. Dunlop Sensitivity differs beyond 1 Hz A.2 Average Spectra Rather good agreement Between STFF-FGM

P. Robert, Croos Cal WS, , ESTEC B. New comparisons (February 2006) All following result has done with FGM high res. Data Provided by FGM Dapclus software, using cal tables downloaded from I.C.

P. Robert, Croos Cal WS, , ESTEC I.1 Bx,By,Bz SC1 I. Spectrograms comparison OK Rest of spin effect, OK

P. Robert, Croos Cal WS, , ESTEC Position in space 18:00 24:00 21:00 22:00 Tetrahedron size about 1200 km

P. Robert, Croos Cal WS, , ESTEC I.2 Bz ALL S/C OK Pb !

P. Robert, Croos Cal WS, , ESTEC I.3 Bperp ALL S/C FGM STAFF 1) STAFF < FGM, 2) STAFF Pb on S/C # 1 Sometimes up to 20% When strong DC field

P. Robert, Croos Cal WS, , ESTEC I.3 Bperp SC1 and SC2 FGM STAFF 2) STAFF Pb on S/C # 1 1) STAFF < FGM, Diff=1 nT or 16% on SC1, Diff=0.5 nT or 8% on SC2 Sometimes up to 20% When strong DC field

P. Robert, Croos Cal WS, , ESTEC II. Average spectra comparison II.1 Bx,By,Bz SC1 STAFF FGM Sensitivity loss STAFF < FGM Sensitivity loss Fs

P. Robert, Croos Cal WS, , ESTEC II.2 Bz SC1 STAFF FGM II.2 Bz SC2 Some differences, as Bperp: Staff < FGM, Best fit with SC2 Fs Parasite spikes

P. Robert, Croos Cal WS, , ESTEC II.3 Bz All S/C Fs Parasite spikes different on each SC Parasite spikes different between STAFF and FGM

P. Robert, Croos Cal WS, , ESTEC III. Wave Forms comparison III.1 Filtered Bx,By,Bz, Bperp SC1 STAFF bug, offset NE 0 STAFF/FGM : difference about 0.5 nT

P. Robert, Croos Cal WS, , ESTEC III.2 ZOOM on Filtered Bx,By,Bz, SC1 Looks the same, but STAFF < FGM About 20% at 2 Hz

P. Robert, Croos Cal WS, , ESTEC III.3 ZOOM on Filtered Bx,By,Bz, SC2 Best fit: About 5 % But not everywhere

16 P. Robert, Croos Cal WS, , ESTEC IV. Background noise Level IV.1 Bx,By,Bz SC1 Starting Time 09:02: Starting Time 09:02: No reliable measurement Fs

P. Robert, Croos Cal WS, , ESTEC IV. Background noise Level IV.2 Bz SC1 Fs No hurried conclusion ! Must be re-computed For other events

FGM - STAFF-SC (from B. Grison) P. Robert, Croos Cal WS, , ESTEC

PRELIMINARY CONCLUSION - This work has be done too quickly: We have to take care with too fast conclusions - Two basic problems has been identified: a) Why perp DC. Field estimated from STAFF SC1 is less that SC2,3,4 ? b) Why perp DC field estimated from STAFF is less than FGM measurement ?. True for perp. DC field,. But also true on the entire spectra,. And also true on the filtered waveforms We have to look on the 4 transfer functions, and carrefully study the onboard calibration - A large amount of work remain to be done: a) Study other cases, in other regions of space in other epochs With or without strong DC field b) See if preliminary conclusions remains the same ; see also HBR mode c) Introduce the new despin utility software, and restart all…

STAFF SC - SA (B. Grison)

FGM - STAFF - EFW(B. Grison)