Logbook from 29 June 2002 to 31 December 2002

Logbook from 29 June 2002 to 31 December 2002

sat 29-Jun-2002

sun 30-Jun-2002

Arrived in Madison; start of the operation on the SXR diagnostic.
Replaced the SXR head of the SXR1 diagnostic with a new one, similar to that of SXR2, with a curved Be filter, the same thickness (16 micron, measured).
Also replaced the cables inside the SXR1 diagnostic with new one: a set of 12 shielded twisted pairs, included in another shield.
Replaced the array of detectors of SXR1: in fact the original one, which was used from the beginning (november 2001), was exposed to the plasma for almost one month (in march 2002, due to an hole in the Be filter), and there are circular alones on the surfaces of the diodes.
Check of the diodes, light tightness etc: ok.

mon 1-Jul-2002

Shot from 1020701001 to 050. 400kA, PPCD from shot 010.
The signals are ok, the level of SXR is slightly decreased (low density discharges, and maybe also poor conditioning of the machine).
Two of the 4 digitizers had wrong voltage range (+/- 5V or +/-2.5V instead of +/-10V). For these reasons the signals of SXR2 are reduced by a factor 2 or 4. At the end of the day the digitizers have been changed and now they are all +/-10V.

tue 2-Jul-2002

wed 3-Jul-2002

fri 5-Jul-2002

Shot from 1020705001 to 228. No plasma ("dummy" shots).
Calibration of the amplifiers borrowed from the HSX experiments. Used a function generator and a "sweeped" sinusoid. This signal has been splitted in two: one to an input of a digitizer (actually, diode 1 of SXR1) and one to the input of the various amplifiers. Also the Femto has been calibrated, in order to get a relative gain between the Femtos and the HSX modules. 10 shots per amplifier.

sat 6-Jul-2002

Shot from 1020706001 to 190.
From shot 8 to 107, 400kA, PPCD.
From shot 108 to 113, 200kA.
From shot 114 to 163, 200kA, PPCD.
From shot 164 to 190, dummy shots to calibrate two HSX modules (HSX4 and 5) with changed gains; these two modules have been disconnected for the shots 31-43 (inclusive).

tue 9-Jul-2002

fri 12-Jul-2002

Shot from 1020712001 to 147. 400kA, PPCD.
PPCD from shot 9.
From shot 27 to the last one of the session (147) the SXR1 probe has been rotated 90 degrees from its original position, to have the fan of lines of sight toroidally orientated. This should give some indication of the helical structure (if present).

mon 15-Jul-2002

Shot from 1020715001 to 154, 300kA, sustained. SXR setup together with IDS.
From shot 138 to 145, F=-0.1.
From shot 146 to 154 F=0.
At the end of the session the amplifiers HSX1,2,4,5,7,8,11 and 12 have been disconnected to change the gains. The modules will be set for measurements of the SXR2 probe @ 400kA, without PPCD.

tue 16-Jul-2002

Shot from 1020716014 to 117.
From 014 to 067 are 400kA, sustained shots; from 068 to 117 are "dummy" shots to calibrate a few HSX amplifiers (whose gains have been changed to get measurements also with the SXR2 probe @ 400kA, non-PPCD discharges.

wed 17-Jul-2002

Maintenance.
Shot form 1020717001 to 025 are "dummy" shots to calibrate three HSX amplifiers modified in the morning. The modifications were made to understand why the HSX1 module does not have the noise between 0 and 5 ms present in all the remaining HSX amplifiers. Indeed the HSX1 module is sligthly different than the other, there are not certain components, and a circuit in the board is open. So we tried to reproduce this "good" behaviour also in HSX2 and HSX12; I have calibrated them, tomorrow we will know if those modifications are the solution to get rid of that noise.

thu 18-Jul-2002

fri 19-Jul-2002

The two SXR probes are left in the 400kA, non-PPCD discharges, configuration. See here to learn how the gains of the amplifiers can be changed and the values to be ised for particular experiments.
Get back to Italy.

mon 12-Aug-2002

Shot from 1020812001 to 150, 300kA PFM, interferometer (L.Marrelli, D.Craig and W.Ding).

tue 13-Aug-2002

wed 21-Aug-2002

thu 22/tue 27-Aug-2002

Bolometric measurements. There is very little signal - and lots of noise. Tried gains from 10^4 to 10^6. Dedicated run on 27 August.

tue 22-Oct-2002

Eight "HSX" amplifiers have been brought back to HSX because they were needed by some student. Now the SXR2 (fixed version) probe works with only 2 diodes (diode 18 and 20). Asked for the construction of a three-gain, externally switchable amplifier with low noise, to replace the missing "HSX" amplifiers.

tue 19-Nov-2002

Shipped one ELAD prototype to MST. Test to compare the new M.Reyfman's amplifiers and the ELAD one started.