AMOR in Time Of Flight Mode
AMOR can be operated in time of flight mode with a large position
sensitive detector. Measuring in this mode involves:
- Aligning the instrument.
- Configuring the histogram memory.
- Configuring the chopper.
- count for some time.
In order to use the histogram memory, it has to be configured. Two
things have to be taken care of:
- Configuring the resolution.
- Configuring the time binning.
See also the general histogram memory
section.
The resolution of the PSD in pixels can be tailored to the experiment
at hand. To this purpose the command psdconfigure is available:
- psdconfigure hm xsize ysize
- xsize and ysize are the resolution of the detector in x
direction (beam width) and y direction (two theta).
Usually this should already have been set up for you.
Configuring the time binning is a two step process:
- Generate the time binning in SICS with the command:
- hm genbin start step nBins
- This generates an equidistant time binning starting at time start,
with stepwidth step and nBins time bins.
- Configure the histogram memory to use the new time binning with:
Please note, that non equidistant time binnings are possible as
well. See the main histogram memory
documentation for details.
The most important thing about the chopper, its rotation speed, can
not be controlled from the instrument control system. It has to be
adjusted MANUALLY at the chopper control PC at the
hall floor. There are two other parameters, however, which are needed
by the detector electronics in order to process the chopper
synchronisation signal properly. The commands are:
- aw
- Read the current value of the acceptance window.
- aw val
- Set the acceptance window to val.
- td
- Read the current value of the time to delay to start.
- td val
- Set the time delay to start to val.