Add support for photon production XS from ACE files #15
Description
Hi, it would be nice to add photon production XS parsing. I recently had to systematically plot these XS in a V&V campaign for a new release of D1S nuclear data libraries and I noticed that the part that should parse photon XS is under TODO.
I ended up writing a very small parser based on the ace object of this repo in order to complete my task and I wanted to try and implement it back here. Unfortunately it seems that to install the package in editable mode and to work on it I need C++ compiler which for IT restrictions reasons I cannot install.
I figured that reporting here the small code would still be useful (at least the pure parsing part) in case someone else would like to complete the job. I only dealt with MF 13 derived cross sections and not MF 12 or MF 16 ones.
Here is the code:
class ParsedAce:
def __init__(self, file: os.PathLike | str) -> None:
self._ace = ace.get_table(file)
self.energy_grid = self._parse_energy_grid()
self.neutron_MT, self.gamma_MT = self._parse_MTs()
self.photon_xs = self._parse_photon_xs()
def get_photon_MTs(self) -> dict:
"""get the photon MTs for all neutron MTs
Parameters
----------
neutron_MT : int
_description_
Returns
-------
dict
_description_
"""
mts_dict = {}
for arb_mt in self.gamma_MT:
num = int(str(arb_mt)[-3:])
mt = int(str(arb_mt)[:-3])
if mt in mts_dict:
mts_dict[mt].append(num)
else:
mts_dict[mt] = [num]
return mts_dict
def _parse_energy_grid(self) -> np.ndarray:
"""parse the global energy grid from the ACE table"""
S_ESZ = int(self._ace.jxs[1])
NE_ESZ = int(self._ace.nxs[3])
return self._ace.xss[S_ESZ : S_ESZ + NE_ESZ]
def _parse_MTs(self) -> tuple[np.ndarray, np.ndarray]:
"""parse the MTs for neutron and gamma reactions"""
MTR_LMT = self._ace.jxs[3]
MTR_NMT = self._ace.nxs[4]
MTRP_LMT = self._ace.jxs[13]
MTRP_NMT = self._ace.nxs[6]
neutron_MT = self._ace.xss[MTR_LMT : MTR_LMT + MTR_NMT].astype(int)
gamma_MT = self._ace.xss[MTRP_LMT : MTRP_LMT + MTRP_NMT].astype(int)
return neutron_MT, gamma_MT
def _parse_photon_xs(self) -> dict:
"""parse the photon cross section data"""
LXS = self._ace.jxs[14]
xs_data = {}
for i, mt in enumerate(self.gamma_MT):
LOCA = self._ace.xss[LXS + i]
index = int(self._ace.jxs[15] + LOCA - 1)
MF = self._ace.xss[index]
xs = []
e = []
if MF == 12 or MF == 16:
pass # TODO
elif MF == 13:
IE = int(self._ace.xss[index + 1]) # energy grid index
NE = int(self._ace.xss[index + 2]) # number of consecutive entries
xs = self._ace.xss[(index + 3) : (index + 3 + NE)]
e = self.energy_grid[IE - 1 : IE - 1 + NE]
else:
raise ValueError(f"MF {MF} not supported")
xs_data[mt] = {"MT": mt, "energy": e, "xs": xs, "MF": MF}
return xs_data