Logbook from 1 June 2005 to 17 March 2006

15 jun 2005

  • Start of the discussion of the next RFXers visit. The main task will be the test of the "multicolor" tomography to estimate the electron temperature.

22 jun 2005

  • SXR_MST_CAL pulsefile created. This will be used to include in the signals the frequency response and phase delay of the SXR electronics

27 jul 2005

  • Vent of MST. J.Goetz replaced the Be foil and the pinhole in SXR1 and SXR2. Now SXR1 has a centered pinhole instead of the 5mm offset pinhole (installed on 22 aug 2004)

1 aug 2005

  • Started the paperwork to sell to MST the four SXR probes

20 aug 2005

  • Arrived in Madison (PF and FB). MST is presently in poor condition. First, an inductor in the poloidal field system failed, and this was a critical failure since it happened in the middle of conditioning to recover from the vent. Then the power to Chamberlin Hall (the building in which MST lives) failed entirely, turning off all power to MST including the vacuum pumps. This resulted in the tank pressure rising to the millitorr range over several hours. This somewhat contaminated the vessel.

24 aug 2005

  • Conditioning of MST is going well, high current plasmas obtained.
  • SXR tomography inserted. SXR1 inserted 124mm (no offset-pinhole), SXR3 and SXR4 131mm. Gain of 400kA, standard. Signals look good. SXR1,D4 and SXR2,D11 not working (electronics?), SXR4,D2 seems broken. After some shots SXR2,D11 started to work again. All probes have been stored only for a few shots, SXR2 always on.
  • Remember the dividers in SXR1! They have been set for lines of sight looking at the edge of the plasma, so they should be changed or, with multicolor measurements, removed. Dividers of SXR2 should be left on since this probe will be used with the usual Be foil (about 15 microns).

25 aug 2005

  • Iso amps of SXR1 disconnected from the diagnostic.

26 aug 2005

  • Internal gains of ISO amps tested (those of SXR1), together with a TLA. It seems that the best solution is to zero the offset of the TLA (@1e6 or 1e7) with the ISO amp gain set to 1x or 5x (it is the same). Also, the diodes should be hooked up to the TLA before zeroing the offset. This way the offset of the 1x, 2x and 5x are 0, 10x has 130mV, 20x has 500mV and 100x (not usable, due to noise level) has 2.6V offset. Since the output currents of the diodes are negative, it is better to have a positive offset to increase the voltage range.
  • Dividers of iso amps of SXR1 changed: now the divider=2 is on channels 5,6,...,16.
  • In the late afternoon the iso amps of SXR1 have been reinstalled. It takes half an hour to connect all cables.
  • Test shots of new electronics: 1050826016 through 1050826019.

29 aug 2005

  • SXR tomography inserted. 400kA standard shots were in program but actually the whole day was 200kA. SXR1 now measures a symmetric brightness profile. Signals of diodes 1,2 and 3 are saturating due to the 3.5V offset. SXR3 and SXR4 are ok. SXR2 has larger noise, mostly the edge diodes (1,3,18 and 20).
  • From shot 1050829069 the input BNCs of TLA of diodes 1 of SXR1 and SXR2 have been swapped. This was done to check if the noise comes from the electronics. Instead, the noise remained on SXR2,D1 but appeared also on SXR1,D1. In fact, the grounding of the two probes has been screwed up with the exchange. At the end of the run the connections of the two diodes have been restored, then the input BNCs of the TLA of diodes 1 and 7 of SXR2 have been swapped.
  • SXR4,D2 is still disconnected from the flange, but the noise is very close to the noise of the other channels, for example SXR4,D1. Is this noise coming only from the diodes, or the electronics, or the entire chain?
  • Looking at the rms of the noise it seems that SXR2 has larger noise than SXR1, and than SXR3 and SXR4 (which are practically the same). In fact, the probes have different grounding on the array of the diodes (see this page).

30 aug 2005

  • SXR tomography inserted. 300kA OFCD.
  • At the beginning of the run the TLA of diodes 18,19,20 of SXR1 have been disconnected in order to modify them from 10^8 to 10^5 and to regulate the offset. From shot 1050830087 the TLA of diodes 1,2,3 of SXR1 have been disconnected in order to compensate the offset. From the same shot the SXR1,3,4 probes have been extracted and the valves closed.
  • D1,SXR2 has still big noise, but divided by 2 (divider), D7 has the same noise. The big noise does not seem to come from the electronics. Is the particular position of the SXR2 detectors?
  • From shot 1050830039 D4,SXR1 started to saturate. Sometimes this diode does not work. Is it broken, like D2,SXR4?
  • Plotting the rms profile for all diodes of a probe during the shot but for times with no SXR signals, it seems that this profile does not change in time, it is the same for shots of different days (for similar gains).

31 aug 2005

  • SXR tomography extracted, only SXR2 is on.
  • Before the shots an isolator/filter on power cords of power supplies of SXR1,2 and 4 TLAs (and encoding system) have been installed. During the day, no differences in noise of the probes have been noted. Cheaters are still present in the power cords.
  • From shot 1050831060 the TLAs of diodes 1,2,3,18,19,20 of SXR1 have been reinstalled. TLAs of diodes 18,19,20 have been modified: gain are 10^5,6,7 like the other amps and the internal capacitor has been removed. All the 6 amps now have offset regulate to zero for 10^7. At the same time, the input BNCs of the TLA of diodes 1 and 7 of SXR2 have been restored.
  • The noise in the edge diodes of SXR2 has a well defined component at 50kHz. Tried to reproduce it on the bench: it appears when the IRD, connected to a TLA and an iso amps, is moved very close to a device like the iso amp or the scope (?). It seems that the hypothesis of different noise amplitude with different positions of the detector is a good one.

1 sep 2005

  • SXR tomography inserted. 200kA PPCD.
  • Before the shots the input BNCs of D2,SXR4 has been disconnected. Actually, the noise is now smaller.
  • SXR tomography extracted after shot 1050901125. While extracting the SXR3 probe the threads of the brass bushing of the threaded rod used to insert and extract the probe broke.

2 sep 2005

  • SXR tomography inserted; SXR3 has been inserted pushing it from the rear flange. 575kA standard and PPCD. During the day the SXR tomography pulsefile has been switched off a few times to allow for some fast test shot.
  • 575kA PPCD started at shot 1050902049. After changing the D4,SXR1 gain from 1x7 to 1e6 this diode started to work. The TLA (@1e7) of this diode is probably damaged. Signals are ok, in shot 098 a few diodes of SXR2 have 20microA of output current.
  • A new bushing for SXR3 has been built at the MST mechanical shop. Replaced at the end of the day without problems. There is also a new speed handle for SXR1.
  • SXR tomography extracted after shot 1050902125. SXR2 gain set to 400kA standard plasmas.

3 sep 2005

  • Only SXR2 on, 400kA plasmas.

4 sep 2005

  • Lots of modification of the SXR tomography electronics for the coming "multicolor" measurements (different Be foils in the four photocameras).
  • Offset of ALL TLA regulated to 0mV for the 1e6 gain. The offset has been measured with the scope (10mV/div) on the output of the isoamp, and with the diodes connected to the TLA. The TLA can be extracted from the plastic grid leaving all cables connected; the four screws which close the amp box should not be tighten too much! This way the dark current of the detectors and the total offset will be compensated. These are the values of the offset with the different gain settings:
    gain offset (mV) gain offset (mV) gain offset (mV)
    1e5 -101 1e6 0 1e7 0
    2e5 -172 2e6 25 2e7 25
    5e5 -486 5e6 0 5e7 0
    10e6 125 10e7 130
    20e6 518 20e7 500
    100e6 2.6V 100e7 2.6V
    200e6 5.4V 200e7 5.5V
    1000e6 saturates 1000e7 saturates

    For the "multicolor" measurements the 10^7 transimpedance will be likely used, and all offsets are close to 0 or positive (remember that the SXR signals are negative). With this offset setting the 10^5 transimpedance has negative offsets, so that the voltage range (5V, due to the TR1612 digitizers - the TLA and iso amps saturates at more than 10V) will be decreased by 100-500mV, but the typical signals (with 1e5,2e5 and 5e5) are usually 1-2.5Vpp (see for example the shots of 2-sep-2005, PPCD@575kA) so that this should not be a problem. This operation took about 4 hours, two persons. Test shots: 1050904002...004; iso amps of SXR1 and SXR4 disconnected, gain all 1e6. In particular the offsets of the channels are not exactly 0 but 0+/-deltaV_adc, where deltaV_adc is about 2.5mV.

  • TLA of diodes D4,SXR1 and D13,SXR2 do not work with 10^7 transimpedance. Since diode 2 of SXR4 is not working, the TLA of this diode has been used for D4,SXR1.
  • After the offset regulation, the iso amps box of SXR4 has been installed upside-down, and the metallic cover has been removed, in order to be able to change the internal gains (from below). The cables for the encoding system are too shorts, so the encoders are present only for diodes 1 through 7, diodes 8 through 20 have no encoder. Also because of the new position of the box, the iso amps have been swapped for the 20 diodes, so that diode 1 uses iso amp 20, diode 2 uses iso amp 19 and so on, ..., diode 20 uses iso amp 1. The TLA, encoders (where present) and the ADC inputs are still the same; this modification has been included in the pulsefile. Test shots:
    • 1050904008, SXR4 has all 1e6
    • 009, SXR4 with various internal gains
    • 010, SXR4 has all 20e6, offset are all +0.5V, D5,SXR4 seems not working
    • 011, SXR4 has all 20e7, offset are still +0.5V, rms is around 200mVpp. D5,SXR4 is working again
    • 012, SXR4 has all 20e7 except diodes 8 and 20 with 1e7 (test to verify the cables), all ok
    • 013, SXR4 has all 20e7 except diodes 9,15 and 19 with 1e7 (again to verify the cables), all ok
  • Then, all channels of SXR3 have been set to 20e7. For this probe the internal gains can be set without disconnecting any cables. Test shots:
    • 1050904014, SXR3 and SXR4 have all 20e7, iso amps boxes without metallic cover
    • 015, same as previous, SXR3 iso amps box with the cover. Seems that the noise is not changing, but it is better to check with plasma. SXR3 noise is about 800mVpp, larger than SXR4.
  • Then, all the dividers on SXR1 iso amps have been removed. Now only diodes 5...16 of SXR2 have 2x dividers. The SXR1 iso amps have been installed. To set the internal gains for this probe one box needs to be removed (diodes 1...8), then the iso amps of diodes 9...20 can be set and then the box should be reinstalled. It takes 10-15 minutes.
  • Test shots with plasma. SXR1,SXR2 have 5e7, SXR3,SXR4 have 20e7. Probe inserted:
    • 1050904016, 200kA, ne about 1, D13,SXR2 saturates. SXR2 has big noise, SXR3 large noise, SXR4 a little less noise.
    • 021, 250kA, still noisy
    • 023, 300kA, noisy, but a small profile can be measured. This shows that the multicolor measurements will not be easy...
  • After shot 1050904027 the probes have been extracted. SXR1 and SXR2 gains have been set to 400kA standard.

6 sep 2005

  • Thicker Be foils have been installed on a spare top flange of the SXR tomography. It seems that up to 80um the foils can be bent. Tried with a 125um but it broke in two. This implies that the 500um which should be installed in SXR4 will be "composed" using only 70-80um foils.

7 sep 2005

  • SXR1,SXR3 and SXR4 probes removed form MST. Be foils replaced.
  • SXR1: the probe is in excellent state. The pinhole foil has not been replaced (already done by J.Goetz on 27 jul). Three foils have been installed, 23+28+29=80um. 23um is the first foil, then 28um and then 29um, which is the top one. Checked the distance between IRD and the edge of the probe: 10.15mm on both sides of the array.
  • SXR3: the probe is in excellent state. The pinhole foil has not been replaced. The previous Be foil (13um) is just a little "colored", so it seems that there is not very much coating. Two foils have been installed, 70+70=140um. Checked the distance between IRD and the edge of the probe: 9.95mm on both sides of the array. This probe has a 5mm ring to increase the distance between the detectors and the pinhole.
  • SXR4: the probe is in excellent state. The pinhole foil has not been replaced. The previous Be foil (13um) is just a little "colored", so it seems that there is not very much coating. Six foils have been installed, 69+79+81+81+83+85=478um; the 69um is the first foil installed, then 79, 81, 81, 83 and 85um, which is the top foil. To install them the foils had to be carefully aligned. Checked the distance between IRD and the edge of the probe: 10.30mm on both sides of the array. This probe has a 5mm ring to increase the distance between the detectors and the pinhole.
  • The insertion tube of the three probes have been greased in order to make the insertion/extraction easier.
  • The IRD arrays have been tested with a pulsating led (1kHz), using a TLA @ 1e5. All diodes work well, except D2,SXR4 whose signals are not negative but both positive and negative. So it is definitely the diode. The array will be replaced after the "multicolor" measurements.
  • All the probes have been tested for light tightness, with a 100W lamp and a TLA @ 1e7: all are ok.
  • Probes installed in MST in the afternoon. D.Craig thinks that the VAT valves have a small leakage (he observed that the MST pressure decreased after the probes have been installed). All valves are closed, probes roughed.
  • All input BNCs of the TLA of SXR2 have been disconnected to test the noise of the electronics of this probe.

8 sep 2005

  • From shot 1050908001 to 046 there are "dummy" plot, without plasma. Noise is about 200mVpp on edge SXR2 diodes (gain 5e7).
  • Shot 047 to 050 have no plasma but the error field correction system has been turned on, and from 0 to 78ms the noise is bigger, about 600mVpp on edge (5e7) diodes.
  • From shot 051 there is plasma, 200kA, and noise is about 4Vpp for 5e7 channels, about 1Vpp for the 1e7 and 1e6 diodes.
  • Noise enters the electronics, independently from the probe. The input BNCs of the TLA have not been grounded, but without the probe there is a lot of noise in the signals.

9 sep 2005

  • SXR2 still not connected to the TLA. The acquisition of this probe is on from shot 1050909001 to 060.
  • A new amplifier is ready fot testing on one of the SXR probe. This is a ISOTLA, that is a linear transimpedance amplifiers plus the isolation stage (opto-isolation), all in the same box. The prototype has fixed 1e6 gain, +/-5V output voltage range, and very low noise (2-4mVpp on the bench). Frequency response is up to 150kHz.

10 sep 2005

  • 400kA and 540-575kA, both standard and PPCD shots. SXR tomography inserted, different Be foils on each probe (multicolor tomography).
  • Shots 1050910001,002,045,046 are dummy shots.
  • Shots 1050910003-053 are 400kA, standard. 1050910034 is a good example (but SXR2 has only D9...12).
  • Shots 1050910054-071 are 400kA, PPCD. 1050910056,058 and 068 are good examples, even if a few or several signals are saturated.
  • Shots 1050910072-083 are 540-575kA, standard. 1050910078 is a good example.
  • Shots 1050910084-123 are 540-575kA, PPCD. Good examples are 1050910089,092,098 and 108 (this last one is maybe the best of the day).
  • D4,SXR1 has its old TLA. D13,SXR2 has the TLA of D2,SXR4, and D2,SXR4 has no TLA. D8...20,SXR4 have no encoder. Gains have been set, at the beginning, to 5e7 for all diodes of SXR1 and SXR4 and to 20e7 for all diodes of SXR3 and SXR4 (20 is internal iso-amp gain).
  • Gains have been changed after these shots: 1050910011, 015, 024, 059, 085, 087, 095 and 116. All changes have been written in the tomography pulsefile.
  • From shot 1050910032 to 044 the "cross-talk" test has been performed. All lemo connectors (on SXR2 flange), TLA input and output BNCs of diodes 1...8 and 13...20 of SXR2 have been disconnected, so that only diodes 9...12 of SXR2 were on. The signals on the disconnected channels are then the outputs of the isoamps, without any input, and they are good (noise is about 30-100mVpp). Shot 043 has only D10,11,SXR2 connected and shot 044 has only D10,SXR2. In all these tests the noise does not seem to change, even in the case when only one diode was connected.
  • Notes for this day:
    • diodes 8...20 of SXR4 have no encoder, but the noise does not seem to change;
    • from shot 1050910021 all encoders of SXR1 and SXR2 have been disconnected. Now all the TLA outputs go to the ISO input directly. Noise does not change. The encoders have been left disconnected;
    • TLA of D4,SXR1 did not work from shot 1050910021 (seemed to have a higher gain), and has been replaced with a spare one from shot 1050910025;
    • D10,11,SXR2 have larger noise than D9,12,SXR2, at the same gain. It seems the noise is "intrinsic" in the channel. Same considerations for SXR4: diodes 8,9,14 are noisy, diodes 15 and 17 are better (they all have the same gains);
    • during the "cross-talk" test (shot 1050910032-046) D9,12,SXR2 had bigger signals than D10,11,SXR2, that is the partial profile was inverted. Cable connections were ok. This was done to the diffusion currents from diodes 7,8 and 13,14, which were not grounded;
    • diodes 1,3,5,8,10,11,16,18,20 of SXR2 have noise bigger than noise of diodes 7,9,12,13,14. In addition, the noisy channels have much more high frequency noise: see for example shot #1050910049 between 12 and 13.5 ms;
    • D20,SXR3 was sometimes saturated at 5V (for example shots 1050910060). Saturation disappeared after the AnalogDevices isolated stage was checked: this chip must be connected properly in order to have good signals;
    • In shots 1050910117-123 D1,SXR2 had the new ISOTLA, fixed gain=1e6. Also D20,SXR2 has been set to 1e6 to compare the two signals. The ISOTLA did not work, since the isolation stage is unipolar (0-5V), while it should be bipolar (+/-5V, like the TLA stage and the present electronics of the SXR tomography).

11 sep 2005

  • Only SXR2 is on. 400kA shots, standard.

12 sep 2005

  • Analysis of the tests made on Saturday. It seems that:
    • the encoding system does not introduce noise to the signals (see for example shots 1050910020, with encoding, and 026 without encoding);
    • the isoamps have 20 to 80 mVpp of noise (without input but with the long cables to the digitizers). So it seems the noise comes in the diodes and the TLAs. Are better shielded cables needed (thinking about the ones used in the RFX tomography)?
    • SXR2 signals are more noisy than SXR1, even if also SXR1 has a few volts (peak-to-peak) when the gain are set to 5e7 (see shots 1050910020 and 026). See also shot 1050910006 to see the differences between SXR1 and SXR2 with all gains equal to 5e7;
  • New prototype of the ISOTLA almost ready.
  • Asked to J.Anderson for a few shots tomorrow, tuesday, during his experiments.

13 sep 2005

  • Evening session with J.Anderson was not successful.
  • SXR1,3 and 4 extracted and all VAT valves closed completely. Encoders SXR1 and SXR2 connected. TLAs of diodes 4,SXR1, 13,SXR2 and 2,SXR4 installed back.

14 sep 2005

  • Work on SXR tomography during maintenance.
  • The offset of TLAs D4,SXR1, D13,SXR2 and D2,SXR4 have been set to 1e6.
  • SXR1, SXR3 and SXR4 disconnected from MST. During this operation the leaking of the three valves has been checked. When the probes are removed, the MST pressure raised from 6e-7 Torr to 9e-7 Torr. A rough pumping has been installed on each valve, and the MST pressure turned to 6e-7 Torr. This is the new procedure when the SXR probes have to disconnected from MST.
  • Tomorrow, Thursday, there will be more multicolor measurements with the SXR tomography. The diagnostic has been set as follows:
    • SXR1 has the front flange of SXR3, with the 140um foil. Replaced the array of detectors with a new one (the previous one ). Replaced the grounding in the socket, now the scheme is the same of SXR3 and SXR4: diodes 1,2,...,10 have the shields grounded on pin1 (one of the two common anodes), and then on the screw next to diode 1; diodes 11,12,...,20 have the shields grounded on pin12 (the other common anode) and then to the screw next to diode 20. Distance IRD - edge of the probe is now 9.85mm. All diodes ok, light tightness test ok.
    • SXR3 has the front flange of SXR1, but with a 254um = 23+58+59+59+60 (measured all the foils and together, this last measure is 254um, less than the sum of the single measurements). 23um is the first foil, 60um is the last foil installed. Distance IRD - edge of the probe is still 9.95mm. All diodes ok, light tightness test ok.
    • SXR4 has still the 478um foil. Replaced the IRD with a new one (diode 2 is broken). Distance IRD - edge of the probe is now 10.325mm. All diodes ok, light tightness test ok.
  • SXR1,3 and 4 installed on MST. Checked all cables of SXR1 and SXR2, all are ok. Connected encoder of diode 8, SXR4.

15 sep 2005

  • 550kA, PPCD shots. SXR Tomography inserted, multicolor measurements. All diodes are working.
  • Before the shots all encoders of SXR4 (diodes 9 through 20) have been connected. D1,SXR2 has the new ISOTLA, fixed gain=5e7 and frequency responce about 25kHz. D10,SXR2 has the new TLA (only the transimpedance amplifier, the iso amp is the usual one), with fixed gain of 1e6 (plus the x5 of the iso amp). This new TLA gives inverted signal, so the output is positive.
  • Shot 1050915012: D1,SXR2 has the same noise than D20,SXR2, even bigger, so the new TLA does not make difference. D10,SXR2 has the same noise than D9,SXR2, thus also this new module does not make big differences. The TLA of D10,SXR2 has been disconnected after shot 035, and the ISOTLA has been disconnected after shot 039; the original TLAs have been used for both channels.
  • It seems the new grounding of SXR1 does not improve the signal-to-noise ratio. Diodes 1 to 10 are noisy, 11 to 20 are good but D12 has big noise. Compare, for example, shot 1050910006 and 1050915018 (SXR1 with all diodes to 5e7). To check if something is wrong with D12,SXR1 the input BNCs of the TLA of diodes 12 and 13, SXR1, have been switched after shot 053. In shot 054 D12,SXR1 is still noisy, but is using the electronics of D13. From shot 069 input BNCs of TLA of diodes 11 and 12, SXR1, have been switched, and again D12 is noisy. So it seems the diode is noisy. These input BNCs have been switched back after shot 115.
  • PPCD shots start from shot 1050915036, until shot 1050915087. Then a few 400kA PPCD shots have been taken.
  • Good examples of high current PPCD are shots 052 (high SXR signals), 054 (QSH rotating, best of the day), 055 (QSH rotating), 057 (high SXR signals, locked, MH), 058 (high SXR signals, locked, QSH), 062 (QSH rotating), 067 (QSH rotating) and 085.
  • After the end of the session (last shot is 109, @18:01) the SXR1,3 and 4 probes have been disconnected to replace the Be foils. Note: it takes about 20 minutes to remove the probe and install the rough pumping on the three VAT valves (two persons).
  • SXR1 iso amps have been disconnected and the dividers (/2) have been installed for diodes 5 through 16. Checked on the bench and installed back. Then worked on the probes.
  • SXR1:
    • checked the connections on the socket: ok.
    • a few Fischer feedthrough on the flange have been tighten.
    • the IRD array used before 14 sep 2005 has been reinstalled. This is to check if the different noise on the signals is due only to the new grounding scheme or to the diodes.
    • distance IRD - edge of the probe is 10.000 mm.
    • Be foil is now 15 um (the foil installed on 27 jul 2005). The original SXR1 front flange has been installed.
    • Tested all diodes with the meter and with one led: all are ok. Light tightness is ok.
  • SXR3:
    • distance IRD - edge of the probe is still 9.950 mm. The 5 mm ring is still being used.
    • Be foil is now 15 um (one of the new foils purchased this year). The original SXR3 front flange has been installed.
    • Tested all diodes with the meter and with one led: all are ok. Light tightness is ok.
  • SXR4:
    • the threaded brass bushing of the insertion/extraction system has been replaced with a stainless steel one. One more is available.
    • distance IRD - edge of the probe is still 10.325 mm. The 5 mm ring is still being used.
    • Be foil is now 15 um (one of the new foils purchased this year).
    • Tested all diodes with the meter and with one led: all are ok. Light tightness is ok.
    • From now on all iso amps use the "external" gains.
  • A few dummy shots to test the electronics: 116 and 117. Everything works fine (@22:45).

16 sep 2005

  • 400kA, standard shots, QSH and F=0 measurements. SXR tomography inserted. On the SXR2 signals positive spikes are present.

17 sep 2005

  • End of PF visit

19 sep 2005

  • SXR2 probe on, the others extracted. 400kA standard plasmas.

22 sep 2005

  • SXR2 probe on, the others extracted. 400kA standard plasmas for CHERS measurements. Positive spikes still present on the SXR2 signals.

23 sep 2005

  • At the beginning of the session a check of the encoder system (with dummy shots) has been made. For each shot all channels are set to the same gain and the encoding voltage pulse is checked:
    • 1050923001...003: do not consider
    • 004: all gain 1e5, encoding ok for all channels
    • 005,006: all 2e5, D19,SXR3 wrong encoding
    • 007: all 5e5, encoding ok for all channels
    • 008: all 5e6, encoding ok for all channels
    • 009: all 2e6, encoding ok for all channels
    • 010: all 1e6, encoding ok for all channels
    • 011: all 1e7, encoding ok for all channels
    • 012: all 2e7, encoding ok for all channels
    • 013: all 5e7, encoding ok for all channels
  • Then, the same has been made but with plasma:
    • 014...017,023: all gain 5e7
    • 018: all 2e7
    • 019: all 1e7
    • 020: all 1e6
    • 021: all 2e6
    • 022: all 5e6
    • 024: all 5e5
    • 025: all 2e5, D19, SXR3 wrong encoding
    • 026: all 1e5
  • A few tests have been made in order to check if powering the TLA with batteries could improve the signal-to-noise level:
    • 027...033: D1,SXR2 with batteries. It seems the noise is the same as before
    • 034...037: D1,SXR2 with original power supply, now batteries on D10,SXR2. Noise still the same
    • 038...039: all input and output BNCs of the SXR2 TLAs have been disconnected, except D10,SXR2. All Lemo on SXR2 flange disconnected, except D10; on all feedthrough a shorted Lemo has been hooked up. The TLA of D10 still with batteries. Encoders connected. It seems that the noise on this single channel remain the same.
    • 040...041: Same as the shots 038 and 039 but only D1,SXR2 is used. It seems the noise decreased.
    • From shot 042 the SXR2 electronics has been restored.

25 oct 2005

  • The SXR tomography has been sold to MST for 1500,00 euro.

17 nov 2005

  • SXR2 has now a stack of four Be foils, 69+70+81+83=303 microns, measured 311 microns (all together, but I do not think this is a good measurement; also, JG used a micrometer with a 2.5 um resolution). The removed Be foils, 15 microns, is coated in one side (as usual), the coating following the directions on the magnetic field lines.

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