Logbook from 16 May 2007 to 27 May 2008

17 May 2007

  • PF arrived in Madison in the evening of 16 May
  • SXR3 and SXR4 have been disconnected from MST in order to remove the 5 mm rings and to get the same geometry of lines of sight for all the probes of Sxr tomography
  • SXR3. The probe is ok. Checked the distance edge of the probe-diode before removing the ring: found 14.15 mm on the D20 side (it was 14.65 mm last time) and the array of diodes was not well inserted in its socket (not measured the other side, towards D1). This should be taken into account for the previous data from this probe --> this array has been replaced on 19-oct-2006 and since then there have not been taken shots, there should be no problem for the previous data. Removed the 5 mm ring and installed back the front cover: due to the thickness of the sandwich of Be foils the curved frame touched the ceramic of the diode array. Installed the 4 screws and tigthened: this was enough to press the cover in its correct position. Doing this the diode array has been surely pressed in the socket. The measured distance diode-edge is 10.15 mm, and another measurement, done after opening again the probe, gives the same number. Test of the diodes with the internal led: all are ok. Test of light tightness (on diodes 1,10 and 20, TLA @ 1e7): ok. The four screws of the front cover has been replaced with new ones (shorter)
  • SXR4. Same actions of SXR3. Checked the distance edge-diode: 15.25 mm (the same as the one that was measured last time). Removed the 5 mm ring. This probe has the same problems as before: the curved frame of the Be foils touches the diode array but after installation of the cover with the (new) 4 screws there is no gap between the cylindric probe and the cover. Probe reopened and measured the distance edge-diode: 10.275 mm. All diodes are ok (tested with internal led) and light tightness (checked on diodes 1, 10 and 20, TLA @ 1e7) is fine
  • SXR3 and SXR4 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. The fiber optic which carries the trigger is disconnected, and the optical transmitter is damaged. Also the trigger of TR1612_5 was disconnected: cable hooked up to the digitizer. Below is the list of the test shots
    • 1070518001 SXR1,2,3 ok, SXR4 only diodes 1,3...10 (due to trigger disconnected)
    • 002 nodata
    • 003 all signals ok. Here the internal leds have not been used
    • 004 function generator (Wavetek model 90) connected to probe SXR1. 1.5V, offset 1.5V, f=200Hz (used the "half" square function). 115 is not working (there have been problems with this TLA also in the past) and even diodes are noisy
    • 005 TLA 155 switched off and then back on. Function generator @ 2.0V. Again 115 is not working
    • 006 encoder 115 disconnected. Diodes 115 and now also 419 are not working
    • 007 115 and 116 cables switched in the flange. 115 now is working, 116 does not see the led. 419 still @ 0V
    • 008 switched back the 115 and 116 cables in the flange and switched the output cables of the 115 and 116 TLAs.115 is not working, 116 is ok. Then TLA 115 is broken. 419 is now ok
    • 009 switched back the output of the 115 and 116 TLAs. Here TLA 115 uses the power supply cable of 111, but still does not work. Diodes 101,102,103 and 120 are ok but the others are @ -5V
    • 010 reconnected power supply cable to TLA of diode 111, TLA of diode 115 without power supply. Again 101,102,103,120 ok but the remaining diodes are @ -5V
    • 011 reconnected power supply to TLA of diode 115. Same story as in shots 009 and 010
    • 012 disconnected all encoder bipolar BNC cables of SXR1. Same results as in shots 009,010 and 011
    • 013 SXR1 TLA/encoder rack switched off and then on. All diodes are now working fine, except 115
    • 014 disconnected all remainig cables of SXR1 encoders but 115 still does not work
  • Function generator connected to SXR4. Amplitude is 2.0V, offset 1.5V and f=200Hz
    • 015 all diodes are working and see the internal led, 419 is saturating. Also here the even diodes are noisy
    • 016 amplitude reduced to 1.7V but 419 still staturated
    • 017 amplitude to 1.5V but 419 still saturated
  • Here I realized the previously the Lemo cables of diodes 419 and 420 were switched in the flange (and the pulsefile contained this). Then what was saturating in the previous shots was D420. Corrected the pulsefile for all shots up to 017 and then switched the Lemo cables of diodes 419 and 420 in the flange. Also, reduced gain of 420 to 5e6
    • 018 all diodes ok, no saturations
  • Function generator connected to SXR3. 1.5V, offset 1.5V, f=200Hz
    • 019 all diodes are ok except 301 which does not see the internal led and there are a few spikes. Here all diodes are fine, no noise in the even or odd numbers
  • The noise in the even diodes for SXR1 and SXR4 is possibly coming from the grounding of the function generator (that is the plug used). In all shots the generator had a cheater in the plug; for SXR1 and SXR4 the plug was connected to an outlet next to the beam injector, while for SXR3 the plug was connected to an outlet in the CAMAC rack #1. Maybe the cheater had not to be used for SXR1 and SXR4, try to get new data in order to check this point

22 May 2007

  • A few test shots to check the electronics of sxr tomography
    • 1070522001 internal leds are off, SXR1 no encoder, diode 420 is not working (damaged TLA)
    • 002 function generator Wavetek model 90 on SXR3. Amplitude is 1.5V, offset 1.5V, f=200Hz, half square function. The generator has been plugged to an outlet on Camac rack #1, without cheater. All diodes of SXR3 are working, except 301. No noise on even number diodes
    • 003 Like 002, but now the generator plug has a cheater. Signals are the same, no changes in noise
  • There is no time to continue with the tests, and to replace the optical transmitter of SXR1 encoder
  • Two new IDL routines have been written to switch on and off the trees in the pulsefile and the sxr tomography acquisition:
    • reset_tree_pf, [/on], [/off] to switch on or off the trees in the Mst pulsefile, useful to take dummy shots only for tomography
    • sxrtomo_set_acq, [/on], [/off], [/sxr2] to switch on or off or on only SXR2 probe of tomography.
  • They both can be run from aurora after typing fd in the terminal after logging in

24 May 2007

  • Test shots for checking the sxr tomography:
    • 1070524001 internal leds are off. All signals are fine, and SXR2,3,4 encoders are ok. SXR1 encoder to be repaired today
    • 002 SXR1 internal led on, function generator Wavetek model 90, amplitude 1.5V, offset 1.5V, f=200Hz, half square function. The generator has been plugged on the isolator where the power cords of SXR1,SXR2 and SXR4 TLAs are connected, with cheater. All diodes are working, but 115 is not. The TLAs of diodes 115 and 120 have been switched last day, but diode 115 is still not working? Even numbers diodes are noisy. Instead all diodes of SXR2,SXR3 and SXR4 have the same noise, even and odd number diodes
    • 003 unplugged and plugged the cables of diode 115 TLA, but that signal is still 0V
    • 004 function generator on SXR4, same voltage and offset, plugged on the isolator of power cords of SXR1,2,4 TLAs, with cheater. All diodes of SXR4 are fine, even number diodes are noisy
    • 005 SXR1 TLAs have been switched off to repair the encoder optical transmitter. Internal led of SXR4 is on but the cheater has been removed from the power cord of the function generator. Noise on even number diodes is now smaller
    • 006 function generator plugged directly on an outlet without cheater. Noise on even number diodes disappeared
    • 007 function generator power cord plugged on Camac rack #1, without cheater. Signals are now very good, similar to those of SXR3 with the internal led
    • 008 same as 007 but using a cheater on power cord of function generator. No changes from signals of shot 007
  • Then the noise on the signals using the internal led depends on where the function generator power cord is plugged. For the future, the outlets on Camac rack#1 should be used
  • Note: the TLAs of SXR3 are powered using an outlet of the Camac rack #1, with a cheater, but the noise in these signals (with plasma) is comparable to the noise of SXR1,2,4 TLAs, which are powered using a different outled and use the isolator and cheaters on the power cords. Thus the noise on sxr signals should not depend on where the TLAs are powered
  • The function generator has been connected to SXR1. Optical transmitter of encoders repaired:
    • 009 led on SXR1 is off. All encoders of SXR1 are fine
    • 010 internal led is on, A=1.5V, off=1.5V, f=200Hz, power of the generator from Camac rack #1 with cheater. All diodes are working except 115. It seems, looking at the signals of diodes 114 and 116, that diode 115 is disconnected. Checked the cable Lemo-BNC and it seems broken. For this and shot 011 the encoders of SXR2 have been switched off to replace the plastic screws of the rack
    • 011 cables Lemo-BNC diodes 115 and 118 switched. Now diode 118 is not working. The Lemo-BNC cable is broken
  • Added a cable to replace the Lemo-BNC cable of diode 115. The old cable has been cut but left in the bunch of cables
  • TLAs of diodes 115 and 120 have been switched back
  • SXR2,SXR3 and SXR4 have now the ppcd 550kA gains. SXR1 is still @ 1e7
    • 016 after a few test shots with plasma of other people, internal led of SXR1 is on (A=1.5V, off=1.5V, f=200Hz). No sxr data
    • 017 now all diodes of SXR1 are working, including 115
    • 018 function generator disconnected from SXR1. gains are those of ppcd 550kA. All diodes of sxr tomography are ok, encoders are working. There is only a problem on diode 301
    • 019 function generator on SXR3 (A=1.5V, off=1.5V, f=200Hz), powered on Camac rack #1 with cheater. Diode 301 is not working
    • 020 switched the Lemo connectors of diodes 301 and 302 on the flange. 302 is not working
    • 021 Lemo of 301 and 302 switched back and switched the input BNCs of TLA 301 and 302. 302 is still not working
    • 022 switched back the input BNCs of TLA 301 and 302 and switched the output BNCs of TLA 301 and 302. 302 is still not working
    • 023 switched back the output BNCs of TLA 301 and 302 and disconnected the two BNCs of encoder of diodes 301 and 302. 301 is still not working
    • 024 switched the input BNCs of iso-amps of diodes 301 and 302. Now 302 is not working
    • 025 switched back the input BNCs of iso-amps of diodes 301 and 302 and switched the output BNCs of the same iso-amp diodes. Again 302 is not working
    • 026 switched back the output BNCs of iso-amps of diodes 301 and 302. 301 is not working
    • 027 the Lemo 00 cable labelled "A1" which goes in the third input of the TR1612_3 digitizer has been disconnected. Signal of diode 301 is bit noise
    • 028 and 029 are strange shots, and Aurora has been rebooted
    • 030 the digitizer cable of diode 301 has been connected to input 15 of TR1612_5. Pulsefile has not been updated, so 301 signal is still bit noise
    • 031 now diode 301 sees the internal led (saved in the pulsefile the modification). Thus the third input of digitizer TR1612_3 is not working (this is the second digitizer input which stopped to work)
    • 032 like 031, all diodes of SXR3 are working, but 301 saturates
    • 033 amplitude of square function to 1.0V but 301 still saturates
    • 034 like 033
    • 035 gain of 301 @ 5e6, and A=1.5V. 301 is now ok
    • 036 internal led of SXR3 is off
    • 037 gains are those of ppcd 550kA, no internal leds on the sxr probes. All channels are working, except 420 which has a damaged TLAs. All encoders are fine
    • 038 like 037. End of the tests
  • Taken a few pictures of the SXR2 probe (to check if the design of the new probe is compatible with the dimensions and stuff aroud the 165P porthole) and of the sxr tomography in general (to be used in some manual of the diagnostic)

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. The SXR tomography has been inserted, but plasma quality is not the best. All probes are working.
  • The insertion of SXR3 and SXR4 was 142 mm but this is 5 mm shorter than the right value, 147 mm. For these shots the diode 1 and 20 should not be considered

20 and 30 Jul 2007

  • 400kA PPCD, sxr tomography inserted, gain all @ 5e7. On 30 Jul various density, up to ne=1.35. Some good shots for sxr analysis and for tentative Te0 calculations
  • For these two days the cables from BNC output of iso-amp of diodes 211 and 220 (sxr2) to digitizer were not switched, while the cables of input of iso-amp were switched. For some reason (possibly during a check of the iso-amp box of sxr2 on 19 jul) these two output cables have not been installed correctly. The input and output cables are switched in order to switch the iso-amp of these two diodes (see 9 oct 2006). At the end of the day the cables have been switched and the error has been corrected in the pulsefile, so that diodes 211 and 220 continue to use the iso-amp 34 and 28, resp.

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. Hardware changes made to reverse direction of Ip, in preparation for tomorrow's run. Good examples of MH and QSH plasmas until shot #57

1 Aug 2007

  • Conditioning to high Ip with direction of Ip reversed, sxr tomography inserted
  • Ran PDC for two hours in the morning, then ramped up to high Ip; standard plasmas looked good, with good density control; midway through the afternoon, another minor explosion occurred at 4980 V on the main bank; repairs made and a few test shots run up to 4980V 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
  • Ran a few high Ip standard plasmas first, then PPCD; no significant technical problems occurred, but quality of PPCD was not great (high m=0 activity); density due only to recycling was larger than normal (and larger than desired), probably due to insufficient conditioning stemming from earlier technical problems

3 Aug 2007

  • Ip set back to normal direction
  • Check of the ratio SXR1/SXR2 and SXR3/SXR4 in time, for shots of 2006 and 2007 (tomography in two-foil configuration, 303 microns for probe 1 and 2, 761 microns for 3 and 4). The ratio SXR3/SXR4 remains stable at a value of about 0.97 (different than 1.00 due to small differences in thickness of the Be filters), while SXR1/SXR2 increases with time, with values starting at 1.05 and going to 1.20-1.30 in these days. This is probably due to the coating of the SXR2 filter. The shape of the SXR2 profile remains the same, indicating a uniform coating of the foil. A correction factor should be sufficient to take into account this effect

10 Aug 2007

  • Started the construction of the 6 additional channels for the nex SXR2 probe (TLA and iso-amp and a few cables)

16 Aug 2007

  • checked the input 11...14 of digitizer TR1612 #5 of the tomography: all channels are working normally. There is a spare TR1612 that can be used when the new SXR2 probe will be installed; another digitizer can be found from another dignostic which do not use all the channels
  • shot for these tests: 1070816005...009

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)
  • For some reason diode 11,SXR1 has a 1x gain but 2x is set (maybe is the knob on panel). Rotating a few times the knob seems to solve the problem. Changed the gain in the pulsefile from 2x to 1x for this diode for shots 1070822001...050

23 Aug 2007

  • Analysis of data from SXR tomography. Aluminum radiation compromises the signals with Beryllium filters less than about 150 microns (plotting the signals versus the cut-off energies of the Be foils in a "multicolor" shot). Modeling the signals assuming bremmstrahlung radiation produces good fits to the data, using density and temperature from FIR and Thomson diagnostics. In QSH plasmas, an island is visible in the reconstructed SXR image. In high current (> 500 kA) plasmas, the axis is shifted of the geometric center by 8 - 9 cm, larger than is usual, and gradients in the SXR emissivity are large. In some shots the profile is hollow very close to the center

24 Aug 2007

  • 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
  • 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
  • Also in this day diode 11,SXR1 has a wrong gain, it is 1x but 2x is set, for all shots (see also 22 Aug). Changed the gain in the pulsefile from 2x to 1x for this diode for shots 1070824001...101

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
  • Diode 11,SXR1 with wrong gain, 1x instead of 2x (see also 22 and 24 Aug). Changed the gain in the pulsefile for this diode from 2x to 1x for shots 1070827001...007. From shot 1070827008, after rotating the knob of the gain a few times, the gain was set correctly to 2x

28 Aug 2007

  • Full day of good quality (~ 60 - 70%), fully diagnosed 530kA PPCD plasmas, reversed plasma current
  • Sxr tomography inserted
  • Before the beginning of the experimental session, the iso-amp of diodes 1 and 20,SXR1 has been swapped: iso-amp of diode 120 is working fine, and this modification should solve the problem of the wrong gain (1x instead of 2x) on diode 111. Pulsefile modified to take into account the swap. After the modification both channels are working fine
  • In the evening the electric field was rewired for normal direction

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. Sxr data only for 303 um (SXR1 and SXR2)

30 Aug 2007

  • Installation and test of the 6 new SXR2 channels (for diodes 202,204,206,215,217 and 219)
  • Offset of the new TLAs have not zeroed; in addition, iso-amp of channel 206 is not working (-7V on output of iso-amp for all gains)
  • Many dummy-shots have been taken to check if the new channels are working. The reference signal (output of the function generator) is diode 201, output of the new channels is alway diode 213. The gain set on the new channels has been saved in the pulsefile always for the same diode, 213
  • All channels except 206 are working, but since the offset of the TLAs has been not zeroed, maybe the tests will be repeated next week
  • Encoder system of the new 6 channels has not been tested
  • A list of all these shots can be found here

31 Aug 2007

  • Offset of the new TLA zeroed (with 1e6 gain set)
  • Isoamp and encoder box of new channels of SXR2 dismounted to check the channel 206. One pin had a bad connection and has been repaired. The box has been mounted back

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
  • Now also the encoder of SXR1 is not working
  • The list of the test shots can be found here

11 Sep 2007

  • In one of the IRD array we tryed to solder the "blind" diodes (the ones before diode 1 and after diode 20) to the common anode but by mistake the adjoining pads on the ends of the array had been linked together. This means that diode 1 and 3 are linked and also diode 18 and 20

13 Sep 2007

  • After a small modification (reduced the resistance in the electrical to optical converter from 220 ohm to 100 ohm to make the current bigger) now SXR1 encoder is working. We think the Jorway 221 output #9 was overloaded, after adding the fifth electrical to optical converter for SXR2). SXR1, D11 did not work, the output cable from isoamplifier to digitizer was not connected, and has been connected
  • The six new channels of SXR2 now are correctly working (checked with signal generator and scope)

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 20th, 2002

4 Oct 2007

  • Asked for 1-2 days of high current (and probably PPCD) for tests of the newly modified, insertible x-ray probe in November 2007 just before the APS meeting

10 Oct 2007

  • The "old" SXR2 detector has been disassembled. The Lemo feedthrough can then be put on the new unit. The array holder (cylindrical probe) should be cut down about a centimeter in length and then aluminum welded to the new insertion shaft. Of course, this means it will be permanently mounted and cannot be replaced on the "old" unit
  • The Be foil exposed to the plasma was badly coated. A SEM ( Scanning Electron Microscope) pict of the foil can be taken. This should help to get a good estimate of the thickness of the deposits and maybe some elemental anaysis
  • Also the IRD array which was incorrectly gold ball bonded has been picked up and is going to be changed to what we wanted. It should be back in a few days

26 Oct 2007

  • P.Weix reported that people are bumping their heads into the bottom framework of the SXR equipment on MST. A solution to fix this problem should be figured out
  • The welding of the new SXR2 probe will be ready by Tuesday Oct 30

28 Oct 2007

  • Due to Air France labour dispute all flights to US have been cancelled. Pf still in Italy

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. All parts of the new probe are now ready but... there are not the holes on the probe tip and the rear container for vacuum
  • Leak tested the rear flange with the Lemo feedthroughs. One of the Lemo were leaking but the problem has been resolved by checking its fixing and replacing the o-ring. Leak test was then fine (leak rate wes even better than the Lemo specification)

31 Oct 2007

  • 21 new internal cables of SXR2 has been prepared, using teflon coaxial cable
  • The IRD array with the blind diode grounded is back but... a few diodes have been disconnected from the pin pads. This array is not usable

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
  • The internal cables are ready and have been soldered to the teflon socket. Grounding layout: diodes 1,2,...,10 are grounded together and to pin 1 and screw next to that pin; diodes 11,12,...,20 are grounded together and to pin 12 and to the screw next to that pin. This is exactly the same layout of the other probes, so that all the tomography sxr camera are the same, and each uses all of the 20 diodes of the array (even though diodes 1 and 20 are not working due to the "blind" diodes)

2 Nov 2007

  • Tryed to install the new socket but the inner of the SXR2 probe tip had been modified to increase the available space. After that the cables and socket have been installed, together with the "stimulus" led
  • A new IRD array has been installed on the new SXR2 probe; the original one has been damaged during the assembling. Lemo plugs connected to the flange. The new SXR2 detector has been assembled. All electrical connections have been checked and are ok. Powered the internal led and checked the output of the 20 diodes: all are working. Note that the led induces a larger noise on the even number diodes (the led is in fact on the even diodes side of the array)
  • The new SXR2 detector has been leak tested but a KF40 extension is not available so the probe tip has been extracted almost to the end. The small holes in the probe tip are then between the two o-rings of the vacuum probe-lock and the detector seemed to leak

3 Nov 2007

  • A KF40 extension has been found and used to leak test the new SXR2 probe: no leaks are present
  • Installed the Be foils on SXR2. The one exposed to the MST vacuum has been replaced with three new foils. The Be foils are then (18+23+28) + 70 + 81 + 83 microns; the first three foils have a total thickness of 69 microns as the replaced one. The foils have been installed in that order, with 18 as the exposed one and 83 as the last one. The total thickness is then 303 microns, the same as before and the same of SXR1
  • The distance between the edge of the open SXR2 probe and the surface of the diodes is 9.975 mm
  • Light tightness test. With the four small holes on the SXR2 probe tip covered with black tape the light from a 100W lamp is not seen by the diodes (a gain of 1e9 has been used with a Femto amplifier). After removing the tape the light enters in the probe. A small tube has been placed on the detector in order to simulate the probe inserted in the 1.5 inch porthole. In this case the probe is light tightned, but with a gain of 1e8; the maximum gain of the SXR amplifiers is 5e7 so it should be fine
  • The new SXR2 detector has been installed on MST and connected to the roughing line. Pressure of MST did not change and the roughing vacuum decreased down to 12 mTorr after a few hours
  • The cables from the SXR2 flange to the amplifiers inputs have been installed and connected. Also the new cables from the iso-amps outputs to the BNC panel on Camac rack #1 have been connected. These cables are RG58 and have been made during FB visit in August-September 2007
  • Patch cables from this BNC panel to the digitizer inputs have been installed and connected. Since two inputs in two digitizers are not working, to test all the SXR2 channels (including the 6 new channels) diodes 301 and 401 have been connected to these bad digitizer inputs

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

5 Nov 2007

  • Pulsefile and software upgraded to include the new amplifiers of SXR2 and the new insertion position. Valid from shot #1071105036

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. This could be due to the thickness of the Be foil of SXR1 and SXR2. This is true in particular for low density plasmas; at higher density (pellet) the sxr Te is fine

7 Nov 2007

  • Today is a run day dedicated to the sxr tomography. Probe SXR1 and SXR4 inserted; the insertion rod of SXR3 is damaged so it has been inserted by simply pushing it. Tried to insert also SXR2 but the probe tip touches the centering teflon o-ring (the between the CF-KF adaptor and the gate valve). The valve has been left open but with the probe extracted
  • Shots from 001 to 018 are between 300 and 520kA, standard. After that the session has been stopped to remove the SXR2 probe in order to fix the insertion problem. From these first measurements it seems also that light is entering the new probe through the 4 small holes drilled on Nov, 1st
  • SXR2 probe tip modified and "rounded". A Be foil of 18 microns has been installed to better check the new electronics. Then the detector has been reconnected to Mst
  • Shots 019...043 are test shot to check the electronics and the internal led
  • Late in the afternoon the gate valve of SXR2 has been opened and the probe has been inserted without problem. Shots 044...054 are test shots @ 525kA, standard. Shot 1071107045 is the first one with data from the new SXR2 detector. Everything is working, apart some noise in diodes 208,209 and 210

8 Nov 2007

  • Another day of tests on the new SXR2 probe. Today the Femto amplifiers has been used again on the sxr tomography
  • Shots 001.008 are dummy shots; three Femto amplifiers have been connected on diodes 208,209 and 210 after shot 005
  • Shots 009...037 are 400kA standard shots. These shots show that:
    • the encoder system does not introduce any additional noise on the signals
    • Femto and the custom made TLAs are basically the same, no differences in noise level
    • without iso-amp (output of the amplifier directly to the Camac) the noise is bigger
  • At the end of the day the four sxr detectors have benn removed from Mst. The four valves have been roughed (this is necessary since a couple of gate valves are leaking)

9-11 Nov 2007

  • Worked on the Sxr poster for the APS meeting

12-15 Nov 2007

  • In Orlando for the APS meeting

16-21 Nov 2007

  • All sxr detectors have been tested on the bench and checked. All probes are fine. The Be foils have been removed, the first one (the one exposed to the plasma) has been replaced. In addition, 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. In almost all Be foils the actual thickness (in microns) have been incised. A 5 mm ring has been installed in all probes in order to increase the distance between the pinhole and the diodes, now of 15 mm. Checked the "zero" and the insertion positions of all the probes. Finally the probes have been light tested. The four small holes of SXR2 have been closed with small screws; now the light tigthness is perfect even at an amplification of 1e9 (Femto)
  • In the evening of 21 Nov the SXR2 probe has been installed on Mst. After that the machine 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. SXR2 has been removed from Mst

22 Nov 2007

  • SXR2 has been leak checked: no leaks. Installed back on Mst and rough pumped. After closing the four holes in the probe tip there are no problems in the vacuum, and the internal volume of the detector is in vacuum through very small apertures in the probe tip (between the front plate and the 5 mm ring)
  • Shots 001-004 are tests on SXR2 electronics, with and without the internal led. Seems like diodes 201...205 and 214...220 are not working (saturated at -5V)

23 Nov 2007

  • Shots 001-005 are test shots of SXR2 electronics. SXR2 TLA and iso-amp power supplies switched off and back on. The -5V saturation disappeared and all diodes are working
  • With the internal led (Wavetek model 90, amp=off=1V, f=1kHz, positive square function) seems like diodes 204 and 206 have 5e6 gain and not 1e6. Checked the amplifiers: iso-amps and encoders are ok, the two TLAs are not working

26 Nov 2007

  • TLAs of diodes 204 and 206 repaired: found a few wrong resistors inside
  • Two new dividers 1e6 and 1e7 have been built. Tested using a TLA: they work fine
  • The DC calibrator box (with 20 BNC outputs to calibrate all amplifiers of a probe in a single shot) has been modified to include a precise divider of 5e6. This should be fine to calibrate all gains of 1,2,5 x 10^6,7 (10^5 is not used)

27 Nov 2007

  • Conditioning @ 500kA, 1071127001-150 (001-003 are test shots). Poor density control. SXR tomography not inserted, valves closed. All channels are working fine

28 Nov 2007

  • Another day of conditioning @ 500kA, 1071128001-124. In shots 125-197 the amplifiers of SXR1 and SXR2 electronics have been DC calibrated (only gains 1,2,5 x 10^6,7; 10^5 is actually not used - better maybe to switch it to 10^8). See also 29-Nov: SXR2 DC calibration has been done again (and that one is the right one)
  • Before the shots, SXR1 has been removed from Mst to check the "zero" position (that is the position of the probe tip when aligned with the porthole plane). In fact, the measurements made on this diagnostic on 16-21 Nov are wrong. The "zero" indication on the diagnostic ruler has been updated. Diagnostic installed back on Mst 45 minutes later and rough pumped
  • These are the new "zero" and insertion positions (probe tip 26 mm out of the porthole plane, the same for all of them) of the sxr detectors with 5 mm rings on the probe tips (all values refer to the rulers on the diagnostic, except SXR2 which has no ruler and the positions are determined using Al pieces of the exact dimensions):
    Probe Zero (mm) Insertion (mm)
    SXR1 83.0 109.0
    SXR2 95.5 121.5
    SXR3 105.0 131.0
    SXR4 105.5 131.0

    For SXR2 the Al gauges should be used to position the probe. In particular in order to close the VAT valve the probe must be retracted slightly farther than the cylindrical "SXR2 Retracted" gauge

29 Nov 2007

  • Digitizer #3 (TR1612_3) has been swapped with a new one (by J.S.Sarff). Shots 1071129001-005 show that all inputs of that digitizer are working. The old digitizer has been consigned to JSS. Sometimes the cable of the trigger of digitizer #2 has to be checked in order to get the data in that module
  • After the hardware meeting all patch cables from Camac BNC panels to the digitizers have been (better) mapped. This is the final configuration, valid from shot 1071129007:
      TR1612_1
      slot13
      diode
      patch
      cable

      TR1612_2
      slot14
      diode
      patch
      cable

      TR1612_3
      slot15
      diode
      patch
      cable

      TR1612_4
      slot16
      diode
      patch
      cable

      TR1612_5
      slot16
      diode
      patch
      cable
      input 1
      SXR1, 1
      L1
      input 1
      17
      Q1
      input 1
      13
      U1
      input 1
      9
      C1
      input 1
      5
      G1
      2
      2
      L2
      2
      18
      Q2
      2
      14
      U2
      2
      10
      C2
      2
      6
      G2
      3
      3
      L3
      3
      19
      Q3
      3
      15
      U3
      3
      11
      C3
      3
      7
      G3
      4
      4
      L4
      4
      20
      Q4
      4
      16
      U4
      4
      12
      C4
      4
      8
      G4
      5
      5
      M1
      5
      SXR2, 1
      R1
      5
      17
      V1
      5
      13
      D1
      5
      9
      H1
      6
      6
      M2
      6
      2
      R2
      6
      18
      V2
      6
      14
      D2
      6
      10
      H2
      7
      7
      M3
      7
      3
      R3
      7
      19
      V3
      7
      15
      D3
      7
      11
      H3
      8
      8
      M4
      8
      4
      R4
      8
      20
      V4
      8
      16
      D4
      8
      12
      H4
      9
      9
      N1
      9
      5
      S1
      9
      SXR3,
      1
      A1
      9
      17
      E1
      9
      13
      J1
      10
      10
      N2
      10
      6
      S2
      10
      2
      A2
      10
      18
      E2
      10
      14
      J2
      11
      11
      N3
      11
      7
      S3
      11
      3
      A3
      11
      19
      E3
      11
      15
      		 J3
      12
      12
      N4
      12
      8
      S4
      12
      4
      A4
      12
      20
      E4
      12
      16
      		 J4
      13
      13
      P1
      13
      9
      T1
      13
      5
      B1
      13
      SXR4,
      1
      F1
      13
      17
      		 K1
      14
      14
      P2
      14
      10
      T2
      14
      6
      B2
      14
      2
      F2
      14
      18
      		 K2
      15
      15
      P3
      15
      11
      T3
      15
      7
      B3
      15
      3
      F3
      15
      20
      		 K3
      16
      16
      P4
      16
      12
      T4
      16
      8
      B4
      16
      4
      F4
      16
      19
      		 K4

  • Note that diode 419 and 420 are swapped on the diagnostic flange. Shot 007-016 are tests
  • SXR2 electronics DC calibrated in shots 017-046; this is the right calibration, the one made on 28-Nov on SXR2 is not valid (there was a different digitizer, with possible different relative calibration factors among the various inputs). 047-049 are other test shots, 050-074 are rfp shots (no data on SXR tomography) and 075-078 are other tests on tomography electronics. So far only SXR1 and SXR2 have been DC calibrated

30 Nov 2007

  • High current (>500kA) ppcd shots, from 1071130062 to 165. SXR tomography inserted. In shots 001-061 SXR4 electronics has been DC calibrated
  • First shot with actual signals on the "new" SXR tomography (5 mm rings in all detectors) is 1071130074 (standard 500kA plasma but with a little signals on all diodes)
  • Rfp shots begin at 062; ppcd begins at 082. Sometimes ppcd has been put off to recover density control
  • Good examples are shots 083,106-108,117,120,121,125,126,128,129,131 and 147. There are a few qsh with mode rotation, and one example of locked ppcd plasma
  • Lemo connectors of diodes 201 and 209 have been swapped from shot 083 (inclusive). Seems like electronics of 209 is too noisy so that diode has been connected to the electronics of diode 201 which now is not usable
  • In shots 168-200 the SXR3 electronics has been DC calibrated. Shots 201-205 are test shots. 204 is the final one, with the SXR tomography extracted and all gains set for high current ppcd (like today). All amplifiers, iso-amps and encoding system are working; a few notes:
    • iso-amps of diodes 111 and 120 have been swapped
    • iso-amps of diodes 211 and 220 have been swapped (iso-amp of 220 has 1x = 2x)
    • Lemo connectors of diodes 201 and 209 swapped in the diagnostic flange
    • Lemo connectors of diodes 419 and 420 swapped in the diagnostic flange

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)

21 Dec 2007

  • The new 5 detectors from IRD have arrived. These arrays have the two end elements shorted to ground. They have been put the RFX cabinet on 2nd floor

23,26 Dec 2007

  • EBW measurements. SXR2 camera observation of antenna yields a signal on diode 202, 219 and 220. The signal does not vary much with plasma current or power. Electrical noise is possibly significant (and has been reduced), but further work is needed to understand the SXR signals

7 Jan 2008

  • SXR2 camera measurements during EBW injection. In PPCD a strong SXR signal is seen on outboard chords (in contrast to earlier results in standard plasmas in which a strong signal is seen inboard)
  • It really is a hard job to retract the SXR2 probe; started to make a screw-drive probe retractor. It should keep things nice and straight for insertion and retraction

21 Jan 2008

  • Some interesting results obtained with the SXR2 camera during rf injection. During PPCD seen some x-rays on channels 220, 219, and sometimes 218. Unfortunately the chords do not intercept the plasma directly in front of the antenna where deposition is expected

April 2008

  • Started the discussion of RFX-mod and MST comparison experiments
  • Reference standard MST discharge @ 400kA: shot 1080415030. This is not one "sustained" plasmas, but the startup Bt... waveforms will be similar regardless. This is a purely self-reversed plasma, as usual for MST. Bt reverses at about 4 ms in this shot. The Bt waveform is controlled with only two banks. There is a startup Bt bank which provides the vacuum Bt and a reversal sustainment bank which is switched in once (self) reversal is achieved.
  • Reference PPCD : shot 1080415050, and other later shots, from this day. PPCD has been applied starting at 10 ms. The startup settings were about the same as in #030

26,28,29,30 Apr 2008

  • Confinement studies in RFX-similar plasmas (high density, high current, F > -0.1). At 500 kA, the plasma did not operate well for density greater than 1.5 x 10^13 cm^(-3). At 400 kA, somewhat more negative F (-0.2), obtained stable plasma operation for density = 2 x 10^13 cm^(-3). 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 TLAs 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, where currents as low as 10nA (or lower) are expected

19 May 2008

  • Replaced the VAT valve of SXR4 (45P,300T) during an up-to-air of MST

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 (edge diodes shorted to ground). A few Be foils replaced on SXR1 and SXR2 (the ones exposed to the plasma and two foils on SXR2 which seem to be different than the others). Probes ready to be reinstalled on MST

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 (1080523001-014)
  • Shot 012 is a test shot of the entire electronic layout. All amplifiers, iso-amps and encoding system are working, except:
    • iso-amp of 111 not working, thus iso-amps of diodes 111 and 120 have been swapped
    • iso-amp of 211 has 1x = 2x, thus iso-amps of diodes 211 and 220 have been swapped
    • something not working for diode 209, thus Lemo connectors of diodes 201 and 209 have been swapped in the diagnostic flange
    • signal of diode 406 noisy
    • something not working for diode 419, thus Lemo connectors of diodes 419 and 420 have been swapped in the diagnostic flange
  • From shot 013 the TLAs of diodes 109 and 110 have been replaced with the modified TLAs with 10^8 gain
  • Shot 014 is an example of the noise in the SXR signals with the new programmable power supply of MST

25 May 2008

  • The new TLAs with 1e8 have been tested with plasma. Data acquisition (only SXR1) on from shot 1080525061 to 078. Gate valve closed in shots 061-073, probe inserted in shots 074-078. At 400kA (see for example shot 074) still difficult to have some useful signal, better at 500kA (shot 078)

27 May 2008

  • Discussion of the present status of the SXR tomography and near term plans
  • End of PF visit

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