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

PSL work

Koji and I will be in the PSL today for replacing IO_MB_M2 as a preparation of the high power laser.

Please do not change the PSL piezo alingment and MC1/2/3 DC biases because they are our alignment references.

Need to reboot h1seih45, I/O chassis disruption.

All models have stopped on h1seih45 at 1073754093, having suffered an ADC timeout.  It's possible that the timing fiber was disconnected for work, not sure of the cause.  I am going to reboot the computer after removing it from the dolphin network.

Computer rebooted, all models are running.

This was necessary because the model stopped running when I swapped ADC 1 and 2 ribbon cables in the IO chassis.

X arm work

I started working on the arm cavity alingment this morning, we have flashes of 400 counts on the transmitted PD (ALS COMM), the refl PD drops from 19500 to 19000, and a spot is clearly visible on the ETM camera (scren shots attached). This can sort of lock for a few seconds.  I'm heading to the X end to look at the locking. 

 

Also. MC1 misalinged so we can see green on the ITM without confusion from the IR. 

corner locking today: L2P on M1 stage of PRM and PR2 adjusted, PRM crossover measured, BS length actuator looks OK.

[Stefan, Kiwamu]

We are now in the process of checking/adjusting the suspensions as our length actuators.

• We adjusted the L2P balance in the M1 stage of PRM and PR2.
  • This was done by applying a big offset in the LOCK L filter of the M1 stages and corrected the L2P by putting a non-zero gain in their DRIVEALIGN L2P.
  • As for PRM, we simply looked at the REFL camera and adjusted the L2P such that the beam doesn't move with the length offset.
  • As for PR2, because we didn't have an intuitive sensor, we adjusted it by looking at REFL_DC when PRX is locked.
  • This eventually allowed us to offload low frequency feedback to the M1 stages. Because the M1 stages take care of low frequencies below 1 Hz, we don't have to an L2P adjustment at high frequencies.
  • H1:SUS-PR2_M1_DRIVEALIGN_L2P_GAIN = 0.0045
  • H1:SUS-PRM_M1_DRIVEALIGN_L2P_GAIN  = 0.006
     
• PRM crossover frequency was measured to be approximately 10 Hz (see the attached).
  • M2 gain was at 0.2.
• We then locked PRY and actuated on BS to see how the length transfer function looks like.
  • The UGF was set to be about 10 Hz by lowering the gain so that the control doesn't suppress BS's length signal at high frequencies.
  • Only FM6 of M2 LOCK FILTER in BS was enabled to make the entire transfer function look more like a pendulum, namely 1/f^2.
  • Indeed the length transfer function was 1/f^2 above 10 Hz and looked good (see the attached).
• Also, we copied the filters for the BS oplev loops over from the L1 to H1 directory.
  • The pitch loop looked helpful in the sense that it reduced the RMS of the motion.
  • The yaw loop may not be necessary at this point because the dominant disturbance seems mainly at 0.2-ish Hz which is out of the oplev control band.
  • For now, we leave the yaw loop off as it doesn't look doing something useful at this point. (Though we probably will need it when we use BS to lock the Michelson.)

One thing I am confused at this moment is the length transfer function of PRM and PR2. I did the same TF measurement as for the BS length drive for comparison, and found that the TF were 1/f above 10 Hz rather than 1/f^2 (see the attached). There must be some stupid reason because otherwise we wouldn't be able to lock PRX or PRY. I will revisit this issue tomorrow.

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

ENDX Ion Pump

I noticed that LLO was running their main ion pump at 7kv in the end station. Ours was set to 5kv.

Today at 22:30 UTC I set the voltage to 7kv. The immediate response has been a small increase in pressure at PT510. We'll watch for a few days and see where it goes.

 

2f demodulator installed

[Dick, Daniel, Koji]

The POP 2f demodulator unit previously installed on row 28 of the ISC R2 rack (c.f. this entry ) was replaced with the 2f demod unit.
This unit has a 24MHz LPF and a 80MHz HPF on CH1 and CH2, respectively, forming a diplexer configulation for 18MHz (2xf1) and 90MHz (2xf2) signals.
Therefore, the temporary power splitter for the POP 2f path was removed.

Because of this action, we expect that the demod phase for the POPAIR18 and POPAIR90 were changed.

The 3f demods (CH3/4) still have the power splitter. This will be removed when the 3f diplexer unit is installed on row 27.

We also cleaned up some of the RF cables:

- The REFLAIR9 cable plugged on row 34 is now routed through the patch panel on row 27.
This means that the demod phase of the REFLAIR_A_RF9 was changed.

- The cable for REFL9 was made and connected to the demodulator on row 34.

- Unnecessary connectors/cables were removed from the patch panel on row 29.

L to Y Cross Coupling on H1-SR2

   Last set of TFs on H1-SR2 showed a longitudinal to yaw cross coupling at 1.51 and 2.77Hz. I adjusted the Coil Holder and recentered the BOSEMs.
 
   There were only two of the four Coil Holder Mounting Brackets installed, (which may be a source of the noise in this suspension and a contributor to the cross coupling) when the earlier TFs were taken. The missing two Mounting Brackets required modification due to misaligned mounting slots. These modifications were not completed in time to be installed on the suspension before it was moved to the LVEA. One of the Mounting Brackets was modified correctly; and has been installed on the suspension. The second Mounting Bracket was not modified correctly and will need to be reworked before it can be installed. Three of the four Mounting Brackets are now clamping the Coil Holder to the Weldment. 

   I have started a new set of TFs on H1-SR2, to see if the BOSEM adjustment and the addition of the third Mounting Bracket will improve the performance of the suspension over that revealed in the earlier TFs.