Virgo Roma Tor Vergata

Tue Jun 23, 2009 8:19 pm by Alessio

Task performed by Campagna, Canuel, Marque, see Virgo logbook entry #23340

As the ring seems to change in time (at least with the temperature of the laser), we decided to install the thermal camera on the NI bench as well (all optics, hardware and software was ready).
After the installation, the images are reported in the first plot.
Then, we imaged the ring on a screen af...

[ Full reading ]

Comments: 0

Tue Jun 23, 2009 8:13 pm by Alessio

Task performed by Vajente, Marque and Canuel, see Virgo logbook entry #23339

This morning, we took the opportunity to put back the thermal camera on the WI TCS bench.
We realigned the setup also (mirror + 2 lenses + camera) in order to have all the optics at the same height.
Note: The height of the beam is a 10.5mm there whereas all the other optics on the bench are adj...

[ Full reading ]

Comments: 0

Fri Jun 19, 2009 9:19 am by Alessio

In the both bench we (Maurizio and I) have installed the Photodiodes to the replacement of Power Meters.
The Photodiode 13300 has been mounted in the NI bench and the Photodiode 13249 has been mounted in the NI bench.
Both PDs are equipped with low noise pre-amplifiers with a gain of 100 from DC to 30kHz (assembled in the E-lab of TOV).

We report the calibration for both P...

[ Full reading ]

Comments: 1

Fri Jun 19, 2009 9:12 am by Alessio

Today we tried to install the thermal cameras for the TCS beam monitoring. The cameras should be installed on the beam reflected by the beamsplitter that recombines the CH with the annular heating. The whol;e setup was simulated with Zemax and according to the simulation the suitable optics have been purchased. We started from the WI.

We immediately realized that the sizes of the opti...

[ Full reading ]

Comments: 0

Tue Apr 21, 2009 7:22 pm by Alessio

Since it was noticed that, starting from a certain time, the power read by the power-meter of the NI TCS gives negative values in the region of the minimum transmitted power (see entry TCS NI power calibration), we repeated the calibration. Results are plotted in the figure.
The new calibration relation is: Pni(W)=5.247*Pr_TCS_NI_Mean-0.054
Before (see CH beam splitter replacement) it ...

[ Full reading ]

Comments: 0

Thu Mar 12, 2009 5:48 pm by Alessio

Since the WI laser is injecting noise in the dark fringe (see Virgo Logbook entry 22321), today we investigated this issue by replacing the power meter with a photodiode.
First of all, we noticed that the controller is not working properly: even if the knob is competely turned to the maximum, the laser is still working in pulsed mode instead of continuous mode as it should be. This is very ...

[ Full reading ]

Comments: 0

Wed Feb 18, 2009 7:39 pm by mdipaolo

In the configuration file TCS_18feb i have modified the values of offset and scaling factor with new values for the following channels:

- TCS..WI_Power_mean
- TCS.._NI_Power_mean

The new values are indicates in the last entry (CH beam splitter replacement (2) ).

Comments: 0

Wed Feb 18, 2009 6:57 pm by mdipaolo

With the Help of entry to LogBook ToR Cascina "MatLab
Images", I report the curve of Ring + Central Heating until to 12th
February, when we replacementd the Beam splitter.

In the following the images of the thermal camera:




...

[ Full reading ]

Comments: 0

Thu Feb 12, 2009 6:46 pm by mdipaolo

Today we have replacemented the original Beam Splitter (II-VI) that we calibrated to Tor Vergata (see for details the entry "Polarization vs rotation of the beam splitter (2)" in Tor Vergata Section).

We have put the beam splitter in a particular position in order to have a minimum polarization. After this we have controld the setup and alignment the bench NI and WI.
...

[ Full reading ]

Comments: 1