==================
VITESS Version 2.2
==================

---------------
General Changes
---------------

 Stop
------
Now all modules enable stopping a simulation without
loss of data. But we cannot guarantee for the correctness of partial
results at the moment. We will use this version to check it. If
you use this feature, please tell us about your experience.


 Fresh
-------
The new function 'Fresh' removes the current instrument from the
screen, so that you can start to build a new instrument.  Attention:
The function is executed at once. There is no question, if you have
already saved the instrument.


Instrument Parameters
---------------------
The consideration of 'Gravity' and a 'minimal weight' (= minimal
current = cutoff probability) is now a parameter of the whole
simulation. This value is given to all modules. These global
parameters are represented in the parameter list by --X instead of -X
(X for f, F, ...)

At the moment, Gravity is considered in the following modules: all
Sources, Chopper_disc, Spacewindow, Spacewindow_multiple, Guide, and
Bender.  Minimal weight is considered in all sample modules, Guide,
and Bender.

The 'Buffer size' that is changed quite seldom is moved to the menu 'Options'.


Small Changes
-------------
- Using the 'Save' function, the original name is suggested.
- The modules in the Log-File are numbered.
- Some explanations are improved (input and output file, abutment loss)
- The function counting the number of lines is improved.
  (That caused problems, if there was no CR at the end of the file or too many of them.)
- It is possible now to prevent the writing of an output file by giving "no_file"
  as the name of the file.
  "no_file" can also be given as the name of the input file (instead of giving nothing.)
- The number of default files is increased so that there is an example available for
  every kind of input file.
- The default extensions in the 'open file' and 'save file' procedures are improved.


Examples
--------
There is 1 new example of an instruments and 3 others are changed
to achieve that most of the modules can be found in any of the
instruments.
The results of a run at one of our computers are saved in a directory
'reference' for each example. So it is possible for every user to check
the installation on his computer.


 Tools
-------
We have added a small program for calculating chopper phases and
appropriate aperture angles in a system of disc choppers. The idea is
to calculate the data that have to be given in the module
Chopper_disc. (See also 'ChopPhases.txt' in the directory 'TOOLS'.) It
can be started separately or from the Tools menu.
If you have also written tools that might be helpful for other to do
their simulation, please send it to us.
(email: vitess@hmi.de or email-list: vitess-l@hmi.de,
 see http://www.hmi.de/people/fromme/mojo.html)


---------------
  New Modules
---------------

Version 2.2 contains 2 new modules, the module 'Bender' and 'Monitor2_y_divy'

Bender
------
The Bender module is similar to the Guide module using the bender
option. The main difference is that the 'bended guide' consists of
several straight parts that form a polygon section. In contrast, the
bender surfaces are circles.
The entrance and exit position of each surface and its radius have to
be given in file, called 'surface file'. The lengths of the channels are
constant at the moment. All benders that can be described in that way
can be simulated.
As it is a lot of work to write and to change this file, there is a possibility
to generate it. The model for that is:
The bender consists of channels. Each channel consists of so-called layers.
The layers are parallel. The channels need not be parallel; a distance
between the entrance and/or the exit of the channels can be given.
In the future, a cross-over between the layers and a variation of the channel
lengths will be realized. (Unfortunately this is already included in the GUI.)

Visualisation of the bender refers to the G2 graphic library and may
be viewed during simulation and as graphics file (bender.ps / bender.png) afterwards.


Monitor2_y_divy / Monitor2_y_divy
---------------------------------
This is another possibility to look at the properties of the neutron beam.
The divergence in one direction is plotted against its position in the same direction.
This is possible for the vertical direction (Monitor2_z_divz) and the
horizontal perpendicular to the beam direction (y_divy).


Visual
------
The module 'Visual' can now also be used on the Windows platform.
All versions now use the G2 graphic library. In contrast to earlier versions,
a picture file  (visual.ps for Windows, visual.png for Unix)
is stored during the simulation and can be viewed afterwards.



---------------------------
Changes in Existing Modules
---------------------------

Source:
------
- The number of neutron sources that can be given in the item 'name of
source' has been extended. (See list by clicking to the item label.)
It is now possible (and normal) to choose the moderator by giving the
appropriate name instead of giving the temperature. The temperature
needs not be given any more, if the 'name of source' or the 'wavelength
distribution file' is given.

- In the 'user time distribution function' the time values are
expected to be in millisec (instead of sec) as in the rest of the
package. A reading error is corrected. (See also example:
backscattering instrument at ISIS, directory IRIS_DIR.)

- The former 'scaling factor' is now renamed to 'total flux at
moderator' for all sources. This is also given as an output value for
all sources.

- The calculation of the solid angle for large divergences is improved.


sample_inelast / sample_elasticisotr / sample_powder
----------------------------------------------------
The calculation of the current behind the sample was corrected.


Sample_powder / Sample_sans
---------------------------
For a spherical powder-sample and a cylindrical SANS-sample, the path
through the sample was not calculated correctly for some sample
orientations. This is corrected.


Sample_powder:
-------------
The structure factor file could not be read because of a wrong
path. This is finally corrected.  (This should already have been
corrected in the last version. But something went wrong. We want to
apologise for that.)

Detector:
--------
Correction: Choice detector grid ON - OFF was mismatched.

