Thank you to all those who responded to my posting regarding bursts of
noise in my 29Si CPMAS experiments and, specifically to Deane and Rich.
The problem is the result of rf. noise from the MAS pneumatic unit. The
noise is being transmitted through the spin counting cable to the probe.
The noise disappears when the counting cable is disconnected or if the
pneumatic unit is turned off. The in-house solution is to filter out
the rf and pass the kHz counting signal with suitable capacitors.
... and wouldn't ya know... I just had the pneumatic unit returned from
being serviced.
Beware to all those looking at 39 MHz using a Bruker pneumatic unit.
Many thanks to all as always.
Glenn
Dr. Glenn A. Facey
NMR Facility Manager
University of Ottawa
ph (613) 562 5800 ext 6077
fax (613) 562 5170
gafacey_at_science.uottawa.ca
www.science.uottawa.ca/nmr
Received on Tue Nov 04 2003 - 17:19:44 MST