Logbook from 28 May 2008

9 Jun 2008

  • Maintenance on Thursday:
    • Diode 211 had a bad iso-amp, this was repaired
    • Diode 111 iso-amp out BNC looks suspicious
    • Diode 419 has a good data train from the iso-amp all the way to the digitizer so the lemo cable out of the probe itself must be bad
    • Diode 416 (the noisy one) showed clear evidence of cross-talk when testing other channels
    • Diode 209 wasn't assessed
  • Many of the labels were made of masking tape and falling off, replaced

16 Jun 2008

  • Worked on the electronics again on Thursday:
    • 111 - isoamp fixed by Dave (I confirmed it now works)
    • 209 - no changes made but couldn't get any bad data
    • 211 - Dave couldn't find a problem with the isoamp, but it seems to be working just fine now, so it's likely a cable
    • 406 - this signal still had noise. I continue to track it down (eliminated the TLA as the problem)
    • 419 - confirmed the bad lemo cable (will replace this week)
  • Shots to look at the tests:
    • SXR1 - 1080612004
    • SXR2 - 1080612012
    • SXR3 - 1080612007
    • SXR4 - 1080612005

11 Jul 2008

  • Machine area open all this week, effort made to track down the bad channels:
    • 111 - Iso-amp was repaired by Dave a while back. All gain settings check out
    • 209 - Tracked problem down to a bad cable between the probe and the TLA. Will replace this cable when Jay Anderson is done using the probe (cable is currently inaccessable)
    • 211 - Iso-amp was checked by Dave and "cleaned up". All gain settings check out
    • 406 - Suspected a faulty cable from TLA to Iso-amp. Replaced this cable this morning and have not seen any noise since (although this noise is intermittent). Will watch this channel in case noise returns
    • 419 - Suspected the probe to TLA cable. Replaced the BNC end of the connector, but intermittent noise persists (though currently gone). Will watch this channel in case noise returns. All gain settings are working
    • 217 - This channel seems dead. Checked the train and the problem is again in the probe to TLA cable, but maybe this is due to Jay's extension cable to use the probe because this was not a problem before. Double checked the rest of the data train to make sure there weren't any other bad components
  • Reorganized all the TLA amplifiers for SXR2 to put them in rough numerical order. There are still 2 that are out of order because their cables were too short
  • SXR4's Iso Amp box does not have a bottom cover on it. A new cover for it will be prepared
  • Remaining to do list is:
    • repair/replace probe to TLA cables on 209, 217 when Jay is done with the diagnostic (if necessary)
    • keep eye on 406, 419 to see if noise reappears

17 Aug 2008

  • PF arrived in Madison in the late afternoon

18 Aug 2008

  • SXR2 probe disconnected from MST. It was installed near the EBW antenna, and has been used by J.Anderson during rf injection one time between June and August. After removing of the probe the MST pressure rised a little; additional tests in that gate valve showed that the valve is starting to leak. A KF40 flange has been attached to the valve and connected to the roughing line. MST pressure went back to the original value
  • New roughing line tubes and valves have been prepared and installed in the 300T location. The previous tubes and valves have been left attached next to the EBW antenna for future use
  • SXR2 has been checked on the bench:
    • d_Si_edge = 15.50 mm on the diode 1 side, 15.45 mm on the diode 20 side. d_Si_edge = 15.475 mm, the same value measured on May 2008
    • all Be foils have been checked and installed back in the same order (see 21 May 2008). The probe has been used only one time and in the first foil there have been noted no signs of coating
    • powered the internal Led (positive square function, 0.1V amplitude, 0.9V offset, 1kHz) and checked all diodes
    • light tightness test was ok
  • SXR2 detector has been installed back in MST at the tomography location and rough pumped

19 Aug 2008

  • All cables of SXR2 have been connected to the flange. TLA amps have been reordered in the rack to have them from 1 to 20 in a decent order (from left to right, from top to bottom). Power and encoder cables of TLA 205 and 216 were too short so lables of TLAs 205 <--> 208 and 216 <--> 217 have been swapped. This change has been recorder in the pulsefile
  • All diodes (all probes) have been connected to their original TLAs and iso-amps, so 201 and 209 cables have not been swapped in the flange, iso-amps of 211 and 220 are not swapped etc (see 23 May 2008)
  • Test dummy shots:
    • 1080819001-023: SXR2. Sometimes, if power cables are disconnected from TLA a few of almost all the amps saturate at -5V. To get them work again power supplies of SXR2 should be switched off, gains set @ 1e6 and p.s. switched back on. If 2e7 or 5e7 should be tested on this probe use a positive square function of 0.05V amplitude (offset and frequency the same). All channels are working, both 1,2,5e6 and 1,2,5e7, but noise level is higher than in the other probes
    • 024-035: SXR1. All channels are working, both 1,2,5e6 and 1,2,5e7
    • 036-045: SXR3. All channels are working, both 1,2,5e6 and 1,2,5e7
    • 046-055: SXR4. All channels are working, both 1,2,5e6 and 1,2,5e7. Sometimes, with no apparent reasons, 406 is very noisy and 408 has wrong encoder pulse. After a few dummy shots they started to work correctly
    • 056-062: SXR1...4 dummy shots @ 1e6 and 1e7

26 Aug 2008

  • First check of the new SXR2 extractor. When the probe is attached to MST is very difficult (if not impossible) to install the extractor so a few modifications are necessary
  • Measured the gauges used to find the correct inserted and extracted position:
    • SXR inserted: 22.10 mm (in correspondance of the arrow)
    • SXR extracted: 124.90 mm
  • Insertion length is then 102.80 mm

27 Aug 2008

  • Installed the SXR2 extractor. A few additional modifications are necessary
  • A small oscillator @ 1.4 kHz to power the internal Led of the four SXR probes has been built. It has three BNC outputs with different currents to allow the testing of 1,2,5e6 and e7 gains. The output currents can be modified with internal variable resistors, together with the output voltage amplitude of the square function. A few tests are necessary to fix the output currents
  • 400kA PPCD shots, so the gate valves of the SXR detectors have been opened, but the probe have been not inserted. Gains are 5e7 for all diodes, modified TLAs of diodes 109 and 110 have 2e8:
    • 1080827001-008: 400kA standard, all channels on
    • 019-022: 400kA PPCD, all channels on
    • 023-123: 400kA PPCD, only diodes 8-13 of SXR1,SXR2 and 9-12 of SXR3,SXR4 on
  • These are the results:
    • SXR2 signals are very noisy, just as during the test shots of 19 Aug
    • Even if the signals are low, it seems that there are no problems in the Be foil thicknesses. SXR1 and SXR2 have the same core signals (maybe a 0.2% difference is present; in Nov 2007 a factor of 1.125 was necessary to increase SXR2), while SXR3 and SXR4 show the usual 1.5% difference (SXR4=SXR3 x 1.015, the same value observed in Nov 2007)
    • A nice shot to check the signals is 094

28 Aug 2008

  • SXR2 extractor almost ready. Discussion with M.Clark to install a small motor to insert the probe faster and easier

5 Sep 2008

  • In the morning tried to insert the SXR2 probe with the new extractor but it was very hard when the probe reaches the teflon ring for alignment. The extractor needed to be modified again. The modifications were ready in the afternoon but then Mst was running
  • Led oscillator ("stimulus") ready. The three BNC outputs have been labeled as SXR1,3,4 @ 1,2,5e6, SXR1,3,4 @ 1,2,5e7 and SXR2 (both 1,2,5e6 and 1,2,5e7). The internal trimmers have been regulated in order to have enough signals for all probes and all gains.10^8 not available. Dummy shots: 1080905001...025
  • Diode 406 still noisy, at all gains. After a few tests, it looked like it was the iso-amp. Thus, Lemo connectors of diode 401 and 406 have been swapped on the flange of probe SXR4. This is valid from shot #1080905023 (included). The pulsefile has been updated
  • Asked for 4 new Be holders (will be built by the mechanical workshop of the physics department) and 30 Be foils 75 microns thick. These will be used for fast replacement of the Be thickness in one or more SXR detectors

7 Sep 2008

  • From shot #1080907065 to 69 the gate valves of the four SXR probes have been opened and data acquisition set on to check if any signals can be measured during the 400kA F=-0.05 conditioning of Mst in H2. The probes have not been inserted. Gain 5e7 for all diodes, 5e8 for 109 and 110. No signals measured

8 Sep 2008

  • First day of plasmas @ 400kA, standard, F=-0.05, in H2. 89 shots, all with densities between 1.0 and 2.0e13 cm-3
  • SXR tomography has not been used
  • Before the shots, the SXR2 extractor has been finally installed and used to insert and retract the probe. It works well, but it takes up to 5-10 minutes to move the probe in or out. Requested the installation of gears to move the probe with a motor or a portable drill. To align the probe poloidally a bubble lever has been used but a different (and more precise) method should be used. Asked to J.Anderson for a new small laser to install in the probe and use to align the detector with respect to the Mst vessel

9 Sep 2008

  • Second day of plasmas @ 400kA, standard, F=-0.05 and F=-0.2, in H2. 117 shots, all with densities between 0.5 and 2.5e13 cm-3
  • Only SXR1 has been turned on, gate valve open but not inserted. Gain 5e7 for all diodes, 5e8 for 109 and 110. Very low signals

10 Sep 2008

  • Third and last day of plasmas @ 400kA, PPCD, in H2. 101 shots, all with densities between 0.5 and 2.5e13. Shots 1080910033, 042, 061 are good ppcd at density higher than 1.0e13 cm-3. 095 is a good ppcd at normal density
  • All SXR probes have been inserted. Gain 5e7 for all diodes, 2e8 for diodes 109 and 110. Low signals, in good ppcd a little higher but still very noisy

11 Sep 2008

  • Final check of the SXR tomography: all probes are extracted, gate valves shuttered. The probe-lock vacuum interface is rough pumped all time. All cables are connected to the right TLA and iso-amp, the only change is on diode 406: Lemo connectors have been swapped in the SXR4 flange (sometimes there is a problem in the electronics of 406, which seems due to the iso-amp)

TO BE UPDATED

18 May - 5 Jun 2009

  • PF visited MST. Analysis of sxr data and simulations of measurements performed. Worked also on the sxr model in order to include all possible informations from the plasma (including Thomson and FIR data)

TO BE UPDATED

17 Jun 2013 -

  • PF visits MST (arrived on 16 Jun)

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