update on status of MEG

Dear Users As many of you will know, the MEG scanner underwent preventative maintenance earlier this month. We are happy to report that this work was carried out successfully. Due to the re-cooling of the sensors and some calibration work the scanner is working well. The noise floor has improved considerably. However, one of the inherent dangers of this thermal cycling is the potential loss of sensors. Until now we had been very fortunate in that we had not lost any channels but this is no longer the case. Users should take note of the following: 1) "Dead" channels There are 3 channels in the MEG scanner that do not work. These channels are A55, A84 and A237. There had recently been suspicion about the quality of the data from channel 237 and during the maintenance it was confirmed that this channel is not working correctly. On a more positive note this is an electronics problem and will be solved once our new MEG electronics are in place. For now, anyone collecting new MEG data should exclude channels A55, A84 and A237 from their analyses. There will be some minor changes to some YNiC software to allow for channel exclusions. 2) REI board error (ONLY for MEG operators) Although currently stable, we are aware of a problem with one of the electronics boards (the REI board). MEG operators will know when the REI board is not working because of an error message that appears in the ACP window on the Sun work station. For this reason the ACP, DCP, AVP and VIP windows must be open when you are acquiring MEG data so that any problems with the MEG scanner can be tracked. If any of these windows are not open, they can be opened from the "acquisition setup" window in the database on the Sun workstation. Click on the "utilities" menu and from here open the relevant window/s. Please record any faults in the "MEG error log book" (left-hand side of the Sun machine). In the event of an REI board error, please contact a member of YNiC staff. Please do not hesitate to contact me if you have any further questions about these matters. Best wishes Rebecca -- ************************************************************************ Dr. Rebecca E. Millman Science Liaison Officer York Neuroimaging Centre The Biocentre York Science Park Heslington YO10 5DG Tel: +44 (0) 1904 567614 Fax: +44 (0) 1904 435356