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Entry  Mon Jul 23 13:30:06 2012, Jenne, Update, Green Locking, Yarm ALS laser is funny / dying 
    Reply  Mon Jul 23 18:01:30 2012, Jenne, Update, Green Locking, Yarm ALS laser is funny / dying 
    Reply  Thu Mar 14 16:41:48 2013, Jenne, Update, Green Locking, Yarm ALS laser is funny / dying 
       Reply  Thu Mar 14 17:31:57 2013, Manasa, Update, Green Locking, X arm green locked in TEM00 
          Reply  Fri Mar 15 01:57:02 2013, Jenne, Update, Green Locking, X arm green locked in TEM00 
       Reply  Fri Mar 15 02:19:01 2013, Jenne, Update, Green Locking, Yarm ALS laser is funny / dying 
          Reply  Fri Mar 15 15:26:13 2013, Koji, Update, Green Locking, Yarm ALS laser is funny / dying 
             Reply  Mon Mar 18 14:58:15 2013, Steve, Update, Green Locking, repair or replace dead NPRO 
                Reply  Thu Mar 28 07:58:15 2013, Steve, Update, Green Locking, NPRO repair 
Message ID: 8296     Entry time: Thu Mar 14 17:31:57 2013     In reply to: 8294     Reply to this: 8298
Author: Manasa 
Type: Update 
Category: Green Locking 
Subject: X arm green locked in TEM00 

Quote:

Manasa has done some work to get the Xgreen aligned, so I'll switch to trying to find that beatnote for now.

[Jenne, Manasa]

Aligned X-arm green in TEM00.

It was difficult to get the X-arm to lock in TEM00 earlier. Even when it locked, it was just a TEM00 flash. The green was mainly bad in pitch.

I started aligning with the arms flashing in IR and it was still not possible to lock. The second trial was with the arms locked in IR; I lost the green lock when the arms were aligned for IR. I aligned by overlapping the ingoing green with the reflected green visible on the steering mirror. This got the green to lock in TEM00; but still it would only stay that way for 30 sec. Jenne pointed me to Yuta's suggestion of increasing the green refl PD gain. Once I increased the PD gain, the mode stabilized.

I went ahead and centered ALS TRX on the PD and GTRX camera (on the PSL table). ALS_TRX reads 2000+ counts.

EDIT by Jenne:  This corresponds to a power of 550uW on the PSL table, measured before the first out-of-vac steering mirror.

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