Soft x-ray (SXR) Tomography in MST

History

13 October 2000 - The discussion of a SXR diagnostic started during the RFP workshop in Varenna.
April/May 2001 - During the visits of S.Prager in Padova for the Solarex and RFX workshops the decision to build the diagnostic is taken.
May/June 2001 - Building of the diagnostic (at the mechanical workshop of RFX).
July 2001 - Mechanical, vacuum, electrical tests.
27 July 2001 - The diagnostic is delivered to Madison.
21 August 2001 - The diagnostic arrived to Madison.
5 November 2001 - Start of the mechanical, vacuum, electrical test al MST. The logbook of the 5-30 nov visit (pdf file, 48k) can be read here
9 November 2001 - Finally! Diagnostic installed!
19 November 2001 - First measurements
30 November 2001 - Back to Italy; Chijin Xiao will continue the tests on the probe.
14 December 2001 - A new logbook, starting on 3-dec-2001, is ready. See it here.
New year, new shots: PPCD on 9 and 11 january 2002.
25 January 2002 - a good day of operation; all SXR signals do not saturate, Ip=400kA.
1 February 2002 - other good SXR signals during PPCD, and evidence of an m=1 rotating structure.
7 February 2002 - New Femto amplifiers, cables, shielding etc shipped to MST.
20 February 2002 - Everything is ready and we are going to MST; our departure is next saturday (23 February 2002).
24 February 2002 - Start of the preparation of the diagnostic for the next experiments. New logbook, see it here
28 February 2002 - PPCD shots! #82 is a nice example of an m=1 rotating structure
1-5 March 2002 - Experiments: Ephi reversal, sawteeth discharges. On 5 March the probe has been used as a bolometer.
9 April 2002 - The new probe (SXR2, fixed version) has been shipped to MST.
10 April 2002 - New pictures of the SXR2 probe (see the Images section)
17 April 2002 - The probe was taken out and holes have been found on the Be filter. Replaced the filter with a new 12.5 um, measured 18 um, and reinstalled the probe on the machine.
24 April 2002 - The SXR2 probe arrived at MST
29,30 April 2002 - Noise troubleshooting test performed.
20 May 2002 - The new SXR probe, SXR2, has been installed on MST. First measurements.
19 June 2002 - 24 new iso amplifiers connected between the output of the amplifiers (Femto or HSX) and the cables to the digitizers.
30 June 2002 - Replaced the SXR head of the SXR1 diagnostic with a new one, similar to that of SXR2 (curved Be filter). New logbook, see it here
1 July 2002 - First measurments of the new SXR1 and SXR2. Changed the voltage range of two digitizer modules.
5 July 2002 - Calibration of the "HSX" amplifiers.
6 July 2002 - Measurements @ 200 and 400kA, PPCD.
12 July 2002 - Measurements @ 400kA, PPCD, with the SXR1 probe rotated toroidally.
15 July 2002 - Measurements @ 300kA, with SXR probes and the IDS.
16 July 2002 - Measurements @ 400kA, sustained dicharges, SXR & IDS.
18 July 2002 - Measurements @ 400kA, ramp-down shots, F scan.
12,13 August 2002 - 300kA shots with interferometer or polarimeter.
21 August 2002 - Be filter removed from the SXR1 probe; bolometric measurements between 22 and 27 August.
12 September 2002 - SXR1 probe back to SXR measurements.
22 October 2002 - Eight "HSX" amplifiers have been brought back to HSX. Now the SXR2 (fixed version) probe works with only 2 diodes. Asked for the construction of a three-gain, externally switchable amplifier with low noise, to replace the missing "HSX" amplifiers.
19 November 2002 - Shipped one ELAD prototype to MST. Test to compare the new M.Reyfman's amplifiers and the ELAD one started.
7 January 2003 - Started the design of the two new SXR diagnostics to be installed in MST to complete the tomography. New logbook, see it here
22 January 2003 - New amplifiers build by MST electronic workshop and installed in the SXR2 (fixed version) probe; all 12 diodes connected.
21 March 2003 - New measurements scheduled for April.
11 April 2003 - Arrived in Madison.
14 April 2003 - The signals of the SXR2 probe have now a small voltage pulse 10 ms before the shot to indicate which is the selected gain for each amplifier. This pulse is generated by an encoder built in the MST electronic workshop.
17,18,19 April 2003 - new experiments performed (200 and 400 kA, PPCD).
20 April to 1 may 2003 - Several tests performed in the SXR1 diagnostic, in order to reduce noise in the signals
3-7 May 2003 - Internal amplifiers, fixed gain, installed in the SXR1 diagnostic
8 May 2003 - MST experimental session stopped.
15 May 2003 - Started the building of the two new SXR diagnostics (in the RFX mechanical workshop).
26,27 May 2003 - 400 kA PPCD + pellet experiments performed.
2 Jun 2003 - A few 400 to 530 kA shots, nice SXR measurements.
2 Jun 2003 - MST shutdown started; should end by august-september.
9 Jul 2003 - Two CF to KF adapters, together with spare pinholes and beryllium foils, shipped to MST. The adapters will be installed on MST during the vent, while the pinholes and Be foils will be used to replace the old/damaged ones in the SXR2 probe.
28 Jul 2003 - Adapters, pinholes and Be foils arrived at MST.
Sep 2003 - LM and PP changed the pinhole and Be foil of the SXR2 probe. The SXR1 and SXR2 cover have been cleaned (to remove the carbon which we believe can contribute to the covering of the Be filter).
19 Dec 2003 - SXR3 and SXR4 probes arrived at MST.
Jan 2004 - End of the MST vent. First plasma shots.
3 Apr to 17 Apr 2004 - Visit to MST to install the four SXR probes. Tests of the amplifiers (Femto, Mikhail's modules and a prototype of a logarithmic amp). At the end of the visit the four SXR probes have been installed, and 5 diodes of the SXR2 have been connected; the other probes (manipulators) have been left extracted. The logarithmic amp was not suitable for our applications, and the Mikhail's amplifiers have been chosen as the amplifiers of the tomography. After the visit the construction of the new electronics (66 channels, each with a trnasimpedance amp, gain 10^6,7,8, and an isolated amp, gain 1,2,5) started.
26 Jul 2004 - Arrived in Madison. Start of the visit to install the complete tomographic system. New logbbok, see it here
29 Jul 2004 - SXR1 and SXR2 electronics completed and installed. SXR4 electronics almost ready, SXR3 in progress
4 Aug 2004 - SXR4 electronics installed. SXR3 almost finished
5 Aug 2004 - SXR3 electronics installed
7 Aug 2004 - First day of shot. Started @17:30, only 20 shots with all probes extracted
8 Aug 2004 - Second day of shots, 109 discharges, 400 kA both without and with PPCD. First data of the SXR tomography, 64 of 66 channels working fine. Seems that there is too much signals, and 1x10^6 is too high during PPCD shots!
11 Aug 2004 - Working on the grounding of the electronics, to solve a few problems
13 Aug 2004 - A board with three UDT hybride diodes has been installed on SXR1 to test these photodiodes
14 Aug 2004 - A few shots with the three UDT. Worked on the TR1612 and the trigger.
15,16 Aug 2004 - Cutted away the quartz window on the UDT (SXR emission is stopped by quartz!)
17 to 20 Aug 2004 - Shots with UDT on 17, worked on the electronics on the other days. In particular, corrected the ground-loop on MST: it was the ground cable of the SXR4 amps power supply. For this reason, in order to avoid these loops, a "cheater" is used on the plug of the SXR1,...,4 power supllies. From these days the diode 10 of SXR2 has a 50ohm resistor on the output of the TLA to check if a "divider" can work. On 19 Aug these 50ohm resistors have been installed on the output of the diode 5,...,16 TLAs of SXR2. Accidental "vent" of MST on 17 Aug during the removing of the SXR1 probe.
21 Aug 2004 - Shots with the 10 channels ELAD preamplifier installed in SXR1. Diodes 5,...,16 of SXR2 still with the 50ohm resistors. It seems that the diodes with the 50ohm saturate at 2.8V, instead of 5V. At the end of the day we realise that the SXR3 VAT valve is leaking, and this probe cannot be touched.
22 Aug 2004 - Worked on the SXR1 probe to install the 5mm offset pinhole.
23,24 Aug 2004 - Shots with the 4 probes. Only diodes 9...20 of SXR1 available (iso-amps not all ready). The 50ohm on the TLA outputs of SXR2 are responsible of the "clipped" signals (in fact the output stage of the TLA is not powerful enough to drive the 50ohm resistor). From shot #1040823053 all the 50ohm resistors have been removed. A 50+50ohm divider has been installed on the iso-amp output of diode 10, SXR2.
25,26 Aug 2004 - Worked on the electronics. 50+50ohm divider installed on the output of the iso-amps, directly inside the iso-amps box, for diode 1,...,12, SXR1 and 5,...,16, SXR2. All 20 diodes of SXR1 available.
27 Aug 2004 - End of the PF,FB visit. PP remains in Madison.
2,4 Sep 2004 - Shots with the SXR tomography.
7 Sep 2004 - Prototype of a new iso-amp ready, with divider before the output stage: in fact the 50+50ohm divider on the output of the iso-amp gives clipped signals just like the divider on the output of the TLAs.
9,12,17 Sep 2004 - Shots with the SXR tomography. From 17 Sep diodes 1...12,SXR1 and 5...16,SXR2 have the divider inside the iso-amp, before the output stage.
19 Sep 2004 - First DC and AC calibration of the SXR electronics
26,28,29 Sep 2004 - Shots with the SXR tomography. During these shots (high current, up to 550kA, PPCD) the SXR signals saturates at 1x10^6 (minimum gain). To solve this problem we decided to replace the 10^8 transimpedance with 10^5, for all channels but diodes 18,19,20 of SXR1.
5 Oct 2004 - From shot #1041005078 all diodes of the SXR tomography have the new TLAs, with 10^5,6,7 transimpedance. Only diodes 18,19 and 20 of SXR1 have the old values, 10^6,7,8.
10 Oct 2004 - Tuneup of 200 and 550kA shots.
12,13 Oct 2004 - Tuneup of 200 and 550kA PPCD shots.
15 Oct 2004 - 200kA PPCD shots. SXR3 signals not present.
19,20 Oct 2004 - 550 kA PPCD shots.
23 Oct 2004 - J.Sarff and J.Goetz have agreed to learn how to operate the SXR tomography. In particular J.Goetz will be the contact person for the operation of the diagnostic. End of PP visit.
From Feb to May 2005 there were several days of shots with the SXR tomography on. Most of them are 400kA, standard or PPCD.
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 2004 - SXR tomography sold to the MST group. Let's wait for the "official" sell
24 aug 2005 - conditioning of MST is going well, high current plasmas obtained. SXR tomography is working, apart from two-three channels
1 sep 2005 - 200kA PPCD plasma. SXR tomography inserted. 72 channels working good. At the end of the day tried a few 500-600kA shots
2 sep 2005 - 575kA PPCD plasma. SXR tomography inserted and working nice
4 sep 2005 - Modification of the SXR tomography electronics for the coming "multicolor" measurements (different Be foils in the four photocameras). See the logbook for more details
7 sep 2005 - Be foils replaced on SXR1 (80um), SXR3 (140um) and SXR4 (478um)
9 sep 2005 - 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 - The multicolor SXR tomography worked, both on 400kA and 540-575kA PPCD shots. Obtained a few shots with all four SXR brightness profiles during QSH. Tried also the new ISOTLA but did not work
14 sep 2005 - SXR1 has now a 140um foil and SXR3 has 254um; SXR4 is still with 478um
15 sep 2005 - Multicolor measurements, PPCD @ 550kA. Not very good shots but there are a few examples with 4 SXR profiles with the different foils. In the evening the SXR tomography has been restored to "normal" (same thickness for all foils, 15 micron)
16 sep 2005 - 400kA standard shots. SXR tomography inserted
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. The removed Be foils, 15 microns, is coated in one side (as usual), the coating following the directions on the magnetic field lines
21 mar 2006 - PF arrived in Madison in the evening of 18 March. Started the discussion on the coming measurements on 20 March. New logbbok, see it here
22 mar 2006 - Dividers for diodes 5...16 of iso-amps of SXR1 and SXR2 removed. SXR1, SXR3 and SXR4 probes disconnected from MST. Installed new filters on the probes: SXR1 and SXR2 have a 303 um filter, SXR3 and SXR4 have a 761 um foil. All diodes of the three probes have been checked and a test of light tightness has been performed. Everything is ok and the probes have been installed back on MST
23 mar 2006 - During the test of the SXR tomography electronics the SXR2 iso-amps blowed up. SXR2 iso-amp box disconnected again. A condenser of iso-amp D3 exploded. Condenser replaced and all iso-amps checked: all were ok. Iso-amp box reinstalled. Other dummy shots have been taken but SXR2 signals noisy
24 mar 2006 - It seems like this noise on SXR2 signals comes from the encoding system
27 mar 2006 - The SXR2 encoder board was not grounded, and that causes the higher noise in the signals. The board has been grounded using one metal screws to attach it to the box. Noise is very similar to that of other probes. Test shot with SXR1 and SXR4 valves open (but probes extracted): 1060327018
28 mar 2006 - A small leak has been found on SXR1. The VAT valve has been closed. Tomorrow a leak test will be made
29 mar 2006 - SXR1 leak tested. Found three "bloody" Fischer feedthrough. Probe removed from MST and feedthrough replaced; they are those of diodes 4, 5 and 8. Probe tested again: no leaks found. Probe installed back in MST. In addition, added a led inside the SXR1 probe, close to the array of diodes
30 mar 2006 - Worked on SXR2 and SXR3 encoders. Checked channels and all are working fine. Electronics installed back on MST
31 mar 2006 - Gain 2x of isoamp D11,SXR2 is not working. Switched cables IN and OUT of D1 and D11,SXR2 isoamps. From that all channels are working
3 apr 2006 - 550kA, ppcd shots. All probes have good signals, SXR2 is a little bit noisy but data have been obtained for almost all diodes. Nice examples are shots 1060403044...047 and 050,051, very high sxr flux, good signals. In particular 050 seems the highest sxr flux ever recorded. Not all are qsh shot, and not all qsh shots have rotating modes, or modes rotate until the beginning of ppcd
6 apr 2006 - Checked the SXR2 isoamps: all are working fine, switched back the IN and OUT cables of D1 and D11,SXR2 isoamps. In addition, from shot 1060406015 the time window of SXR tomography is from -5 to 80 ms (before it was -5...100 ms)
9 apr 2006 - 550kA, ppcd shots. All probes have good signals, SXR2 is a little bit noisy but data have been obtained for almost all diodes. Nice examples are shots 1060403040...047 and 057...074, very high sxr flux, good signals. In particular 062 seems the highest sxr flux ever recorded. Not all are qsh shot, and not all qsh shots have rotating modes, or modes rotate until the beginning of ppcd
18 apr 2006 - Another 550kA, with and without ppcd shots. All probes have good signals. 1060418083, 095 and 098 are good rotating qsh in ppcd. 077 and 082 have particularly signals, with saturation in several channels; Be1 has 825 (a.u.) in shot 082. Output BNCs of isoamps of D8 and D13,SXR2 were switched, and that's why the SXR2 profiles looked strange. Cable switched back in correct configuration from shot 001. Added a patch in the software to take into account the mistake, valid from shot 1060406001 to the last shot of 1060417
19 apr 2006 - Second day of 550kA, with and without ppcd shots. Good examples of MH and QSH plasmas obtained. All photocameras working well
20 apr 2006 - Calibration of the SXR tomography electronics. D10,SXR1 is the reference. Then the diodes 10,SXR2, 11,SXR3 and 11,SXR4 have been used. The gains of the high current ppcd campaigns have been calibrated. Discussion with B.Chapman about the possibility to modify the SXR2 probe from fixed to moveable. Maybe this is possible using a small valve connected directly to the porthole (without the CF-KF DN40 adapter)
26 apr 2006 - End of PF visit
22 and 23 may 2006 - 515kA pellets on PPCD shots. SXR tomography inserted, two-foil configuration, all channels working fine
22 aug 2006 - 520kA PPCD shots, SXR tomography inserted, two-foil configuration
7 and 8 sep 2006 - 500-550kA PPCD shots, SXR tomography inserted, two-foil configuration
13 sep 2006 FB arrived in Madison
14 sep 2006 - 1060914002-024 are test shots ("dummy" shots) to check that all channels, amplifiers, encoders etc are working. D2,SXR4 is not working, all the remaining channels are ok
18 sep 2006 - 500-520kA PPCD shots for QSH studies with Thomson scattering. SXR tomography inserted, two-foil configuration
20 sep 2006 - 1060920001-012 are "dummy" shot to find out what is not working on D2,SXR4. Diode, cables, TLA, encoder and iso-amp work properly, the digitizer remains to be checked
21 sep 2006 - 1060921001-017 additional tests on D2,SXR4. It seems that the digitizer input of that diode is broken. This is input 8 of digitizer #4 (this input is labelled as "7" in the digitizer panel since these lables start at 0, while in the pulsefile they are numbered from 1 to 16). Check shots 016 and 017: in 016 the digitizer inputs of D2 and D3,SXR4 are switched and D3,SXR4 is not working
25 sep 2006 - Vent of MST. 1060925001-008 are test shots to solve the D2,SXR4 problem. From shot 1060925005 the digitizer inputs of diodes D2 and D3,SXR4 have been switched. It was planned to switch diodes 1 and 2 but instead D2 and D3 have been changed by mistake
5 oct 2006 - PF arrived in Madison
9 oct 2006 - 510kA PPCD shots. SXR tomography inserted, two-foil configuration
11 oct 2006 - SXR1,SXR3,SXR4 disconnected from MST. Be foils replaced, 15 microns installed (the same used in september 2005). Insertion system of all manipulators has been cleaned. SXR4 bushing repaired. Inner cables of all probes checked, no problems found. A new flange, new socket and new inner cables for SXR1 have been prepared, to be installed soon
12 oct 2006 - SXR1,SXR3,SXR4 installed on MST. Vacuum ok. Modified the roughing line of the tomography, now the three probes are pumped using only one line from the main tree
13 oct 2006 - 400kA standard, F=0 and PPCD shots, SXR tomography inserted, 15 um on SXR1,SXR3,SXR4, 303 um on SXR2
14 oct 2006 - SXR tomography inserted, 15 um on SXR1,3,4, 303 um on SXR2. Calibration shots and 400kA standard shot
18 and 19 oct 2006 - SXR1,SXR3 and SXR4 disconnected from MST, thick Be foils installed back. Replaced the inner cables and the flange of SXR1. Internal led installed on SXR1, SXR3 and SXR4
24 oct 2006 - Test of the internal led for SXR1,3 and SXR4 and of a new type of amplifier with remote control of gain
26 oct 2006 - End of PF visit
16 may 2007 - PF arrived in Madison. New logbbok, see it here
17 may 2007 - SXR3 and SXR4 disconnected from MST. Removed the 5 mm ring from both the probes. Probes installed back on MST and rough pumped
18 may 2007 - test shots to check the electronics of the SXR tomography. SXR1 encoders are off. All diodes are working altough the signals of certain diode are noisy
24 may 2007 - a few changes on the electronics, now all channels are working (except 420 which has a damaged TLA)
30 may 2007 - End of PF visit
12 jun 2007 - the mechanical shop of UW Physycs started to build the parts of the new moveable SXR2 probe
11-13 jun 2007 - starting of the high current campaign, with and without PPCD, and with a plasma current up to 585kA
20 and 30 jul 2007 - 400kA PPCD shots, sxr tomography inserted. Data of the 2-color tomography will be used to get a core Te(t) estimate (appling some heavy smoothing and in the signals)
28 jul 2007 - FB arrived in Madison
31 jul 2007 - 550kA PPCD plasmas with multiple diagnostics, sxr tomography inserted; minor explosion during shot #007 at 4980 V on main bank; following repair, good PPCD shots obtained
1 aug 2007 - Conditioning to high Ip with direction of Ip reversed, sxr tomography inserted. Midway through the afternoon, another minor explosion occurred at 4980 V on the main bank; repairs made and a few test shots run at end of day. Sxr tomography extracted after shot #37
2 aug 2007 - 550kA PPCD plasmas with multiple diagnostics and Ip reversed, sxr tomography inserted. Quality of PPCD was not great (high m=0 activity); density due only to recycling was larger than normal (and larger than desired)
2 aug 2007 - 550kA PPCD plasmas with multiple diagnostics and Ip reversed, sxr tomography inserted. Quality of PPCD was not great (high m=0 activity); density due only to recycling was larger than normal (and larger than desired)
10 aug 2007 - Started the construction of the 6 additional channels for the nex SXR2 probe (TLA and iso-amp and a few cables)
22 aug 2007 - PPCD plasmas at high current (> 500 kA), sxr tomography inserted. PPCD quality not great, but a few good shots obtained (Te_TS in the vicinity of 2 keV, tentatively)
23 aug 2007 - Analysis of data from SXR tomography. Aluminum radiation compromises the signals with Beryllium filters less than about 150 microns. Modeling the signals assuming bremmstrahlung radiation produces good fits to the data, using density and temperature from FIR and Thomson diagnostics. In some shots the reconstructed Sxr profile is hollow very close to the center
24 aug 2007 - The toroidal electric field (and plasma current) was reversed, so as to examine asymmetric effects on the electron velocity distribution. Conditioning at high current in standard and PPCD plasmas, reversed plasma current. PPCD quality poor. Density too high and m = 0 mode destabilized. Sxr tomography inserted and acquisition on from shot 1070824061. The week 24-29 aug was devoted to obtaining confinement data, fully diagnosed, in high current (500 kA) PPCD plasmas. Preliminary analysis indicates that for both forward and reversed electric field (or plasma current) electron temperature profiles were obtained with central values about 2 keV, flat to r/a ~ 0.4 - 0.5
26 aug 2007 - 530kA PPCD shots, reversed plasma current. About 20% of PPCD shots were good quality. Sxr tomography not inserted
27 aug 2007 - 530kA PPCD, with some conditioning, reversed plasma current. Sxr tomography inserted
28 aug 2007 - Full day of good quality (~ 60 - 70%), fully diagnosed 530kA PPCD plasmas, reversed plasma current. Sxr tomography inserted. In the evening the electric field was rewired for normal direction. Swapped iso-amps of diodes 111 and 120 (knob of iso-amp 111 possibly not working) at the beginning of the experimental session
29 aug 2007 - Fully diagnosed 530kA PPCD plasmas, normal direction plasma current. Sxr tomography inserted. In the evening, F = 0 plasmas (C1, C2 only) were operated with peak current up to 600 kA
30 aug 2007 - Installation and test of the 6 new SXR2 channels (for diodes 202,204,206,215,217 and 219)
31 aug 2007 - Offset of the new TLA zeroed (with 1e6 gain set). Isoamp and encoder box of new channels of SXR2 dismounted and repaired
1 sep 2007 - The parts of the new SXR2 probe are almost ready. A new VAT valve has been ordered
6 sep 2007 - Second part of the tests on new SXR2 electronics. There are still channels not working, even though (as usual) on the bench everything seemed fine. End of FB visit
13 sep 2007 - Repaired the SXR1 encoder and all six new channels of SXR2
27 sep 2007 - MST was brought up to dry nitrogen today to remove SXR2 from the machine and add a new gate valve in preparation for the installation of the new SXR2. So that's the end of the career of the fixed Sxr probe, started on Monday may 20, 2002
10 oct 2007 - The "old" SXR2 detector has been disassembled. The Be foil exposed to the plasma was badly coated
29 oct 2007 - PF arrived in Madison in the evening
30 oct 2007 - The array holder of SXR2 has been welded to the insertion shaft. Leak test of the rear flange and of the Lemo feedthroughs. No leaks found
31 oct 2007 - 21 new internal cables of SXR2 has been prepared, using teflon coaxial cable
1 nov 2007 - Four holes have been drilled on the SXR2 probe tip (27 mm from the edge of the open probe, right behind the support of the teflon socket) and a hole has been drilled in the rear container to connect the roughing line. In addition, the new internal cables have been soldered to the teflon socket
2 nov 2007 - New SXR2 cables and socket have been installed, together with the "stimulus" led. A new IRD array has been also installed
3 nov 2007 - Leak test of the new SXR2 detector: no leaks found. Installed the Be foils, 303 microns. The new probe has been also light-tightness tested and it seems ok, even though the light could enter the probe through the four small holes on the probe tip. SXR2 installed on MST and rough pumped. Cables installed from the flange of the detector to the digitizers
4 nov 2007 - SXR2 disconnected from MST to find the correct insertion position. Two aluminum parts have been built, one to insert the probe in its measurement position, and the other to extract the probe
6 nov 2007 - Worked on the Sxr data of August 2007. It seems that the sxr Te is underestimated with respect to the Thomson data in low density ppcd plasmas
7 nov 2007 - Run day dedicated to the sxr tomography. Problems in inserting SXR2. Run a few standard shots @ 300 and 520kA and then the SXR2 probe has been removed and modified. A Be foil of 18 microns has been installed. After the modification SXR2 has been inserted without difficults. Shot 1071107045 is the first one with data from the new SXR2 detector
8 nov 2007 - Another day of tests on the new SXR2 probe. Femto amplifiers has been used on a few SXR2 diodes. These shots show that the preset electronic system is working good, comparable to the (expensive) Femto amps
9-11 nov 2007 - Worked on the Sxr poster for the APS meeting
12-15 nov 2007 - In Orlando for the APS meeting
16-20 nov 2007 - All sxr detectors have been tested on the bench and checked. The Be foils exposed to the plasma have been replaced and new foils have been added to the existing ones, so that SXR1 and SXR2 have a thickness of the Be of 408 microns, while SXR3 and SXR4 have 821 microns. A 5 mm ring has been installed in all probes
21 nov 2007 - After installation of the SXR2 probe MST pressure rised to 10-5 Torr instead of the usual 7e-7 Torr. Mst has been leak checked but with no success; in any case it seems that the sxr probes are not responsible of the leaking
22 nov 2007 - SXR2 has been leak checked: no leaks
23 nov 2007 - Checked the amplifiers: all TLAs, iso-amps and encoders are ok, except two TLAs (of SXR2). In the late afternoon the leak in MST has been found: it is the NIRB system
26 nov 2007 - SXR2 TLAs repaired and installed back on MST
27 nov 2007 - Conditioning @ 500kA, poor density control
28 nov 2007 - Another day of conditioning @ 500kA. In the late afternoon SXR1 and SXR2 electronics have been DC calibrated
29 nov 2007 - Digitizer #3 (TR1612_3) swapped with a new one from JSS. New mapping of diodes and digitizer inputs. All channels are working fine. SXR2 electronics DC calibrated again (this is the good one)
30 nov 2007 - High current (>500kA) ppcd shots. SXR tomography inserted. In the morning and afternoon SXR3 and SXR4 electronics have been DC calibrated
2 Dec 2007 - End of PF visit
14 Dec 2007 - Vent to Nitrogen for SXR2 camera installation in a 1.5 porthole (138T, 90P) close to the EBW antenna (138T, -19P)
23,26 Dec 2007 - EBW measurements. SXR2 camera observation of antenna yields a signal on diode 202, 219 and 220
7 Jan 2008 - SXR2 camera measurements during EBW injection
April 2008 - Started the discussion of RFX-mod and MST comparison experiments
26,28,29,30 Apr 2008 - Confinement studies in RFX-similar plasmas (high density, 400 and 500kA plasma current, F > -0.1). Good data acquired
11 May 2008 - PF, LZ arrived in Madison
12-16 May 2008 - Discussion of the comparison experiments recently performed at RFX-mod and MST
14 May 2008 - Modified two TLA to have 10^6,7,8 gains. Added a 10kHz filter to the 10^8 transimpedance. This is to try to get measurements with the two-color SXR tomography also at lower plasma currents
19 May 2008 - Replaced the VAT valve of SXR4 (45P,300T)
20 May 2008 - Started to work on SXR2 probe. Probes SXR1,3,4 removed from MST in the late afternoon. M.McGarry started today her research project on the SXR tomography
21 May 2008 - Worked on probes SXR1,3,4. Diode arrays replaced with the new AXUV-20ELM-G array
22 May 2008 - Probes SXR1-4 reinstalled on MST. No vacuum problems
23 May 2008 - Cables connected to the SXR probes. Test shots of the electronics of SXR tomography. From shot 013 the TLAs of diodes 109 and 110 have been replaced with the modified TLAs with 10^8 gain
25 May 2008 - The new TLAs with 1e8 have been tested with plasma. At 400kA still difficult to have some useful signal, better at 500kA
27 May 2008 - Discussion of the present status of the SXR tomography and near term plans. End of PF visit
9 Jun 2008 - Maintenance on Thursday, worked on the not working channels. Many of the labels were made of masking tape and falling off, replaced
16 Jun 2008 - Worked on the electronics again on Thursday
11 Jul 2008 - Machine area open all this week, effort made to track down the bad channels
17 Aug 2008 - PF arrived in Madison in the late afternoon
18 Aug 2008 - SXR2 probe disconnected from MST, checked and installed back at the tomography location and rough pumped (it was installed near the EBW antenna)
19 Aug 2008 - All cables of SXR2 have been connected. TLA amps have been reordered. All diodes (of all probes) have been connected to their original TLAs and iso-amps. Dummy shots showed no problems for all channels
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
27 Aug 2008 - During the 400kA PPCD shots of today the gate valves of SXR tomography have been opened and the signal levels have been checked. Even if the signals are low, it seems that there are no problems in the Be foil thicknesses
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 o-ring for alignment. The extractor needed to be modified again. Led oscillator ("stimulus") ready. Asked for 4 new Be holders and 30 Be foils 75 microns thick
7 Sep 2008 - From shot #1080907065 to 069 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. 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
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. 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. All SXR probes have been inserted. 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. Electronics ok. 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)
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 - visit of PF at MST. It is planned to run the SXR tomography for PPCD measurements, and to continue the analysis of data both using the SXR model and the magnetic reconstructions

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