from the begining of the week, Xinyi, Aurélien, Viktor and myself started to install a new setup for the Menhir 160MHz oscillator.
the goal is to rich a record power in the FP-cavity.
- the 160MHz Menhir oscillator has been injected in a fiber.
we reached ~ 25mV on 50ohms which is equivalent to 0.5mA in a DET10 photodiode.
=> ~1mW coupled in the fiber => it is not enough to put an EOM and an AOM before the amplifier.
=> one needs to improve the fiber injection.
in fact, I checked the power in the fiber with a powermeter, and it is ~16mW !
at this level of power, one needs to add some optical density before connecting to a photodiode, or it can be saturated.
- we calculated the mirrors position in the SBOX vessel to obtain a 160MHz FSR FP-cavity.
see in attached files, the calculations and scheme in the PPTX file and the Matlab code to get some results.
- we cleaned the optical table and verified with the dust counter that the SBOX environnement is clean.
the 2nd airflow box (from the entrance) seems more dusty (measureed directly close to the top) than the others.
we also opened the vessel and cleaned it.
see the dust measurement inside the SBOX.
- we checked the motors inside the vessel :
=> spherical and plan mirrors translation stage control with the ESP300.
the translation stage have been placed on the middle of their range.
=> the 2 D-shape mirrors translation stage control with PICOMOTORS controller Newport 8742.
- today, Viktor and Xinyi should start the installation of the mirrors mount and make some test to check if the beam is properly propagated inside the FP-cavity, before installing the final mirrors.
the mirror mounts are the Newport SU100TW-F2K zero-drift low waveform distortion : https://www.newport.com/p/SU100TW-F2K
they can accept mirrors with 6-6.35mm thickness => normally the SBOX mirrors from the LMA have a 6.35mm thickness.
see 1st file from this post : https://elog.lal.in2p3.fr/FPC/SBOX+commissioning/174 |