MIF Task List



LSC ASC Overall Design

Frequency Stabilization Servo

The frequency stabilization servo (FSS) is a multi-loop servo system to ultimately stabilize the laser frequency. There are three references used to hierarchically stabilize the laser frequency. The most inner reference is the reference cavity, which serves as the frequency reference at DC. The MC is the second loop, which is ultimately taken over by the CARM loop. Since the FSS loops are high BW, the feedback filters are mostly implemented in analog. Only the part of signals fed back to the mirrors of the MC and ETMs are processed by the digital RTS. The slow thermal control of the laser frequency will also be performed digitally.

Task list:

Green Lock System

We should work in collaboration with the IOO group on the practical implementation of the green lock system. Task List:

RTS code implementation

Implement servo systems with realtime system codes.

Commissioning Planning

Electronics Circuit Design

Design and manufacturing of necessary electronics circuits for interferometer control.
The tasks include:

Here is an incomplete list of circuits

Vacuum Enclosure & Wiring for In-Vac PDs

Some of the core PDs and QPDs have to be placed inside the vacuum. Those PDs will be put in hermetic enclosures. The wires used to communicate with those PDs have to be also vacuum compatible.

The tasks are:

PD Protection Shutter

All the PDs have to be protected against sudden increase of the incident power, for example when the lock is lost. A quick mechanism to deflect the beam path from the PDs is necessary.

The tasks are:

Beam handling during All-In-Vac operation

During the science mode, we want to operate solely on the PDs inside the vacuum. There will be no light coming out to the air at all. The main reason for this is to avoid scattering light problems (things in the air vibrate much more at audio frequencies due to accoustic noise). However, this configuration poses some challenges to us.

First of all, all the light power has to be somehow dissipated in the vacuum. Even though the detection chambers (in which the PDs are installed) are at room temperature, we have to make sure that the heat is properly disposed. If the temperature of the PDs change too much during a lock, we may have slow drift problems.

Secondly, beams from the interferometer are extracted out to the air and detected by large range (but more noisy) PDs for lock acquisition. Once the interferometer is locked, we have to close those windows. Just closing the lid is not enough because the lid will generate a heck of scattered light. We have to come up with a way to gracefully shut down the beam going out to the air. Moreover, just damping the beam is not enough at some detection ports. In order to maximize the light power going to the in-vac PDs (to minimize the shot noise), we may want to change the power ratio between the in-air and the in-vac PDs after the lock acquisition. We probably send more power to the air during the lock acquisition, while we want send most of the light to the in-vac PDs after the lock.

Task list:

Output Mode Cleaner

Design, fabrication and commissioning of the Output Mode Cleaner.

Task List:

KAGRA/Subgroups/MIF/TaskListOld (last edited 2015-08-24 06:14:45 by YoichiAso)