Using ucesb as unpacker stage for R3BROOT
The versatile unpacker generator ucesb can be used as unpacking stage for R3BROOT. This allows the user to write the unpacker using a human-readable specification, rather than in C/C++ code. Thorough checking of the data format comes for free as well. For further information about ucesb, see the write-up.
- Install ucesb (with FAIRROOT version of ROOT)
- Compile your experiment specific unpacker and test it on data
- Produce the header file for R3BROOT including the data structure
- Extract the parts for each detector and level (unpack / raw)
- Install R3BROOT
- Write detector specific readers
- Write or modify your R3BROOT steering macro
- Run the macro
Checkout the most recent version of ucesb from the git repository at Chalmers:
git clone https://git.chalmers.se/expsubphys/ucesb.git
And also checkout the git repository with experiment unpackers (currently only inside GSI network):
git clone /u/htoernqv/repos/upexps.git git checkout 202004_s455
points to your FAIRROOT installation directory!
Compile the empty ucesb unpacker using the same version of ROOT as you used for FAIRROOT.
make -j8 empty/empty
After compilation finished, make sure that the file
exists. This is needed for communication between ucesb and R3BROOT. Set the environment variable UCESB_DIR to the 'unpacker' directory, e.g.
Insert this line at the end of your .bashrc (or other shell login script) to make it permanent. R3BROOT will from now on look for ucesb at this location.
Compile your experiment specific unpacker
Also use the same ROOT version here.
cd upexps/experiment_directory make -j8
Produce the header file
Run ucesb with the struct_writer header generation option
You can skip parts of the following step, if you do the header writing like this
./sNNN --ntuple=<signals>,id=h101_<detector>,ext_h101_<detector>.h # Example ./s483 --ntuple=RAW:TOFD,id=h101_tofd,ext_h101_tofd.h
This will already insert the correct detector names for you, and only extract signals related to the specific detector.
Extract the parts for each detector
At this point the following part of the process is still manual: For this example we will use the RAW level data of the LOS detector.
- Make a copy of ext_h101.h for each detector (e.g. ext_h101_raw_los.h)
- Rename the EXT_STR_h101.h to EXT_STR_h101_raw_los.h
- Delete all contents of the structure with don't relate to LOS
- Delete all contents of the #define EXT_STR_h101_ITEMS_INFO(...) that don't relate to LOS
- Rename the #define statement to match the structure name.
Installation information can be found on the R3BROOT website
Write detector specific reader classes
Have a look at r3bsource/R3BUnpackReader.[cxx/h]. Your detector specific reader class should almost be a copy of this, mostly replacing 'unpack' with e.g. 'raw_los'. And you will have to make sure that in the Read() function your detector specific data containers are filled with the data from the ucesb structure.
Write or modify your R3BROOT steering macro
An existing steering macro for the s438b experiment can be found in
It shows how the R3BUcesbSource class is used and how Readers are added.
Run the macro
root -l path/to/your/macro.C