[Nexus-developers] NeXus @ TOF
Mark.Koennecke at psi.ch
Wed Feb 3 13:11:16 GMT 2010
this is a followup to one of our discussions on one of our teleconferences.
At time-of-flight instruments the flightpath length before the sample
position is a
number of crucial importance. The trouble is that at some instruments
starts with a pulse defining chopper, at others it is determined by the
of the source or by the moderator. Thus we cannot clearly store it in a
group. Creating a special group for this morsel of data is overkill as
there is no other
data to go with it.
Thus I prose to add a data field to NXinstrument with a name of
a documentation saying:
This is the distance between the sample and whatever beam line
component triggers the
zero of time-of-flight. This can be a chopper, a moderator or even the
source. If a suitable
distance is available in a sub group of NXinstrument, this field ought
to be a link to this
distance. Example: if the zero of TOF is determined by a chopper, then
is a link to NXchopper/distance. The usual NeXus rules apply, i.e.
this is usually a negative
number in millimeter.
Given the way we work, I will assume that I can make the necessary
changes to NXinstrument
and start tackling application definitions for TOF at my leisure if I
did not get e-mails of protest
or outrage before Friday.
P.S. I am invited to give a talk on NeXus at FRM-2 in Munich, February, 18.
More information about the NeXus-developers