X arm work today

Alexa, Keita, Sheila, Daniel,

Starting with yesterday's alingment alog 9230, I found some flashing this morning using the transmitted PD.  This lead to a clearly visible 00 mode on the ETM camera.  The final alingments we ended up with are in the attached screenshots. 

The trans PD (ALS COMM) has flashes up to 400 counts, which means that we have about 35 uW (a factor of 10 more than the single shot beam). The refl PD drops from about 19000 counts to about 16000 when the cavity is locked to the 00 mode.  There is also a 02 mode that has about 200 counts in transmission, so about half the power of the 00 mode. 

It seems as though all the previous alingments where we thought we had fringing were red herrings.  I moved the camera on ISCT1 (now using a lens and letting the beam hit a baffle) so that the single shot beam is no longer visible but you can clearly see the cavity modes. 

Since the locking was so unstable we thought of trying to feedback to HEPI as was done in HIFO-Y.  However, the IPC from the SUS to HEPI has been deleted. We either need to add it back or add an IPC directly from the LSC model to HEPI.  Hugo is working on it.   However, the situation that we have seems worse than in HIFO Y, there we would run out of range after tens of minutes, today we are running out of VCO range every few seconds.  Also, we get about 5 fringes per second, which if it is due to motion of the optic would mean 1um per second motion.  We need to investigate if the optics are really moving this much. 

Alexa and I went to the end station to look at what was saturating (we are exceeding the VCO input range it seems).  While we were there we also had a look at the IQ scatter plot on the scope.  One thing is that there is approximately the same amount of signal in I as Q, so this is not a usefull way to try to tune the demod phase.  Keita came out and we tried to measure the transfer function from the laser frequency to the demodeulated signals, however we could not because the lock was not stable enough.  We also tried to adjust the demod phase while watching the open loop TF, this also wasn't sucessfull because the loop did not stay locked long enough for us to get repeatable measurements.  

Alexa and I also looked at the residual AM by misaligning the ITM and looking at the output of the PD.  With the ITM misalinged, we have -33dBm of residal AM at the input to the demod, with it aligned we get some thing around -17dBm. 

Stefan is currently investigating the ISI performance. 

SEI work at WHAM4--Problems with Sensor signals getting to model

We left the LVEA around 3:30 after chasing GS13 signals.  EE/CDS drove our sensor cables at the AA & Interface chasses and confirmed we have signals coming out.  We find now that the HI ISI HAM4 model is incorrect according to the wiring (D1000298.)  Except for the expected difference regarding CPS on HAM2 & 3, the models match.  However, the GS13 & L4C wiring is different.  So we have to change the model or change the wiring.   At the moment we have just H2, V2 & H3 sensor on the ISI plugged in.  We'll continue when the wiring/model gets sorted.

electronics work on ISI HAM4 IO Chassis

Richard, Filiburto, Hugh, Hugo, Dave

In order to track ISI HAM4 signal issues we injected signals into the AA chassis for h1seih45 for GS13 V1,H1,V3,H3 (first two ADC cards of this IOChassis). Signals were tracked through the IOP and h1isiham4 models. Hugo is checking the model against the wiring diagram.

End X activity done for the day

Keita, Alexa and I have returned from end X

offset zeroing script for QPSs

Added an offset zeroing script for QPDs to the svn: asc/common/scripts/setQPDoffsets (SVN revision 6861).

It uses tdsavg to set the four segments to zero, and sets an offset of 4 counts into the sum filter module to avoid a division by zero.

Preconditions: no light on diodes, segment gains have to be -1

Ops Summary

Tumbleweed bailing on X arm
10:07 - 10:28 Apollo moving contents of garbing room from West bay to HAM4 (by hand) (WP 4393)
10:54 Site water sample collecting
11:30 Lightning rod work
13:29 Sheila working at end X

Mitchel, Hugh starting work on HAM4

DAQ Restart, new Beckhoff X1 PLC3 channel list

12:51 DAQ restart, new channel list for H1EDCU_ECATX1PLC3.ini for Thomas' ring heater changes.

I modified the mod_ini scripts to arrange channels in alphabetical order so we actually got new H1EDCU_ECATXXPLCX.ini files for all systems (new channel order) but only H1EDCU_ECATX1PLC3.ini had new/removed channels.

New ini files committed to svn, version 6859.

Jeff B. starting transfer functions on SR2

ETMX HEPI position loop closing Quiets T240s

The large tilt requirement into HEPI for the TMS tilting really accentuated the IPS sensor noise when the HEPI loop was open.  The HEPI had not been commissioned so the tilt was direct drive.  On Friday Jim, Fabrice and I closed those loops and I did my best to restore the previous tilt to the system.  We only got to within ~25urads cause the other loop closings caused more drive to the the V1 corner pushing the IPS to 29900counts with a watchdog trigger at 30000.

See the attached 8 day plot.  The plot shows lots of things but mainly look at the lower right graph with T240 INMON.  The first half of the plot is before the hepi position loops were closed.  The quieter interval in the middle left, was during a noise study and we had no tilt (see the various hepi graphs).  In the middle of the time frame we closed the ETMX HEPI position loops and you see the T240 channel go very quiet.  There are no railing spikes that would have tripped the ISI.  On Monday, Keita offloaded much of the HEPI tilt to the TMS because the HEPI IPS was close to its trip level and TMS needed a little bit more tilt.  You can see the HEPI tilt change in the channel 9 & 12 graphs.  However, there is no change in the noise at the T240 when Keita offloaded HEPI to TMS (I zoomed in and there is no difference in the time series view.)

Bottom line, The HEPI tilt will not cause ISI trips with the HEPI position loops closed.  HEPI could take much of the TMS tilt back if needed.

ETMX Ring Heater

Wrote and installed the code for running the ring heaters.
Added the rough calibration values that Aidan B had recommended for running the ring heaters.

Some data below:
Upper:
Requested Power = 1.00 Watts
Requested Current = .17 Amps
Measured Voltage = 6.85 Volts
Measured Current = 0.16 Amps 
Calculated Power = 1.13 Watts
Calculated Resistance = 42.81 Ohms

Lower:
Requested Power = 1.00 Watts
Requested Current = 0.17 Amps
Measured Voltage = 6.71 Volts
Measured Current = 0.17 Amps 
Calculated Power = 1.11 Watts
Calculated Resistance = 39.47 Ohms

A quick, back-of-the-envelope calculation shows that the ring heaters are working properly. Although their values are a bit different than ITMY shown in ALOG 8816, this is mostly due to only being roughly calibrated.  The next step is to do a long term 4+ hour test to show curvature change and robustness. 

epics gateway between slow controls and cds VLANS restarted

10:51 I restarted the h1slow-cds epics gateway due to Beckhoff IOC work.

Jeff B. starting work on SR2

Done

Mitchel starting work on HAM4

Done

Thomas V. recompiling, restarting PLC3 on H1ECATX1

Done

Kiwamu, Koji replacing beam splitter on H1 PSL table

Breaking for lunch

EX PLL measurements

(Alexa, Daniel, Sheila)

PLL Beatnote:

• Beatnote height of -11.6dBm (or -24dBm before the preamplifier which has a gain of 12dB)
• BBPD reads 5.2mW
• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, rest OFF ---- under this configuration we found the lock was unstable with the input 1 gain at 6dB
• Turning Boost 1: ON, the lock was then unstable with the input 1 gain at 4dB
• We decided the best stable configuration was with the input 1 gain set to 0dB (gives a factor of 2 gain margin)

PLL Open Loop Transfer Function:

• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, Input 1 Gain: 0db, rest OFF
  • EX_PLL_OpenLoopTFmag_BoostOff EX_PLL_OpenLoopTFphase_BoostOff  (collected with SR785)
  • EX_PLL_OpenLoopTF_High_BoostOff/AAAA2.TXT (collected with RF spectrum analyzer for high freq)
  • UGF at 22kHz, phase margin of 50 deg
• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, Input 1 Gain: 0db, Boost 1: ON rest OFF
  •  EX_PLL_OpenLoopTFphase_BoostOn (collected with SR785, need to recollect mag data)
  • EX_PLL_OpenLoopTF_High_BoostOn/AAAA3.TXT (collected with RF spectrum analyzer for high freq)
  • UGF at 26kHz, phase margin of 20 deg

PLL Noise Spectrum -- via IMON of PFD (S1000758)

• PFD test report indicates the board has a noise of ~500nV/SqrtHz from IMON
• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, Input 1 Gain: 0db, rest OFF
  • EX_PLL_Noise_PFD_BoostOff (collected with SR785)
  • EX_PLL_Noise_PFD_High_BoostOff/AAAA4.TXT (collected with RF spectrum analyzer for high freq)
• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, Input 1 Gain: 0db, Boost 1: ON, rest OFF
  • EX_PLL_Noise_PFD_BoostOn (collected with SR785)

PLL Servo Board Transfer Function:

 

• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, Input 1 Gain: 0db, rest OFF
  • EX_PLL_ServoBoard_TFmag_BoostOff, EX_PLL_ServoBoard_TFphase_BoostOff (collected with SR785)
• Input 1 pol: NEG, Common Compensation: ON, Generic Filter: ON, Fast Option: ON, Fast Gain: -8dB, Input 1 Gain: 0db, Boost 1: ON, rest OFF
  • EX_PLL_ServoBoard_TFmag_BoostOn, EX_PLL_ServoBoard_TFphase_BoostOn (collected with SR785)
• Note: DC gain of -30dB nominal

Shot Noise of PLL BBPD:

• Measured noise from laser to be -95dB at 100Hz BW
• Noise of RF spectrum was -100dBm at 10Hz BW