Virgo Logbook

This morning the DF locking was not sufficiently stable to do good tappings or injections, we could only perform these very short injections at the SR-SPRB link:

sine f0,  sine Ampitude   gps (approx)
43 Hz     0.1 V	          1176019408  (too small also in accelerometers)
43 Hz     1 V             1176020031  (nothing in DARM) 
43 Hz     5 V             1176020085  (shaker clipped after a few seconds, the ITF unlocked)

We then devoted the rest of the shift to prepare remotized setups:

at PR-SPRB link we clamped the small shaker and we added one meggit accelerometer using wax (see photos in Figure 1 and 2) (the accelerometer was actually added during yesterday maintenance and named ENV_SPRB_LINK_ACC_Z). The shaker is powered and driven by DAC channel ENV_NOISE_CEB_DetEEroom in ENVnoise.
at the DT cryo trap we clamped the big shaker (see photos in Figures 3, 4, 5) and we can rely on monitor accelerometers ENV_DT_CT_ACC_Z and ENV_DT_CT_FINGER_ACC_Y). The shaker is powered and driven by DAC channel ENV_NOISE_CEB_EEroom in ENVnoise.

We also tested some reference line injections (from ENVnoise Acl client) which do not clip the shaker:

at DT cryo trap:

43 Hz, 0.5 V # line is about 100 times above background in ENV_DT_CT_ACC_Z
121 Hz, 0.5 V # line is about 50 times above background in ENV_DT_CT_ACC_Z (current to shaker 0.9A rms)
213 Hz, 0.5 V # line is about 500 times above background in ENV_DT_CT_ACC_Z (current to shaker 0.9A rms)
423 Hz, 0.1 V # line is about 500 times above background in ENV_DT_CT_ACC_Z (current to shaker 0.2A rms)

at SPRB link (during maintenance):

43 Hz, 1 V # line is about 40 times above background in ENV_SPRB_LINK_ACC_Z (note: 5V clips the shaker, but 3V should be ok)
143 Hz, 0.1 V # line is about 100 times above background in ENV_SPRB_LINK_ACC_Z
243 Hz, 1 V # line is about 100 times above background in ENV_SPRB_LINK_ACC_Z

Figure 6 shows one example of the 243Hz test injection at SPRB link: the accelerometer nearby the shaker sees the strongest line, acc at PR south flange is 5 times below, other acc.s in CEB are a factor 10 to 100 below.

We left both shakers powered and the driving signal connected, but injections off. The headphone set was left in EEroom in charge mode.