levels

For any nucleus, it is possible to access to its level scheme composed of the known levels and decays. Print the known levels as follows:

tknucleus nuc("8B");
nuc.get_level_scheme()->print("level")

[ INFO     ] dataset '8B : ADOPTED LEVELS, GAMMAS' contains 5 levels:
[ INFO     ] Level energy = 0      keV [no uncertainty] ; Jpi: 2+   ; lifetime = 770     (3    ) ms
[ INFO     ] Level energy = 769.5   (2.5  ) keV ; Jpi: 1+   ; lifetime = 35.6    (0.6  ) keV
[ INFO     ] Level energy = 2320    (20   ) keV ; Jpi: 3+   ; lifetime = 350     (30   ) keV
[ INFO     ] Level energy = 3500    (500  ) keV ; Jpi: 2-   ; lifetime = 8       (4    ) MeV
[ INFO     ] Level energy = 10619   (9    ) keV ; Jpi: 0+   ; lifetime < 60     keV [limit value]

The level list can be retrieved using:

tknucleus nuc("8B");
auto levels = nuc.get_level_scheme()->get_levels();

or using a lambda function to filter the levels (e.g. all the positive parity states in):

tknucleus nuc("8B");
auto levels = nuc.get_level_scheme()->get_levels( [](auto lvl) {
    return lvl->get_spin_parity()->get_parity().is_parity(tkparity::kParityPlus);
});
for(auto &lev: levels) lev->print()

[ INFO     ] Level energy = 0      keV [no uncertainty] ; Jpi: 2+   ; lifetime = 770     (3    ) ms
[ INFO     ] Level energy = 769.5   (2.5  ) keV ; Jpi: 1+   ; lifetime = 35.6    (0.6  ) keV
[ INFO     ] Level energy = 2320    (20   ) keV ; Jpi: 3+   ; lifetime = 350     (30   ) keV
[ INFO     ] Level energy = 10619   (9    ) keV ; Jpi: 0+   ; lifetime < 60     keV [limit value]

A level can also been accessed directly by its name (e.g. the first 3⁺ state):

tknucleus nuc("8B");
nuc.get_level_scheme()->get_level("3+1")->print();

[ INFO     ] Level energy = 2320    (20   ) keV ; Jpi: 3+   ; lifetime = 350     (30   ) keV

, or using its energy (the closest level in energy will be returned):

tknucleus nuc("8B");
nuc.get_level_scheme()->get_level(3000.)->print();

[ INFO     ] Level energy = 3500    (500  ) keV ; Jpi: 2-   ; lifetime = 8       (4    ) MeV

The get_level(...) methods return a tkn::tklevel object, and the get_levels(...) methods return a vector of tkn::tklevel objects.

In some cases, a level or a full band is known only relatively to an offset X because the bandhead energy is not known. The level energy in this case is its energy related to the bandhead offset (ex: X+100). The default method get_energy() in this case will return a "nan" value to avoid confusions. To test is a level is known only with an offset, use the method is_energy_offset(). To obtain its relative energy, use the get_energy() with the _with_offset option.

Here are the main method that can be applied on a tklevel:

method name	description
get_energy()	returns the energy in keV
is_energy_offset()	to know is the level is only known relatively to an offset
get_offset_bandhead()	returns the band offset value
get_lifetime()	to get the lifetime in seconds
get_spin_parity()	to get the spin and parity as a tkn::tkspin_parity object
get_spin_parity_str()	to get the spin and parity as a string
is_stable()	returns true is the level is stable
is_isomer()	returns true is the level is an isomer
get_isomer_level()	returns the isomer level (1st, second,...)
is_yrast()	returns true is the level yrast
get_decays_up()	returns the list of decays that populate this level
get_decays_down()	returns the list of decays that depopulate this level
has_comment()	returns true if a comment on this level exists
get_comment()	returns the comment on this level
is_uncertain()	returns true if a the level is uncertain
print()	prints the main level informations (as already used above)

The above methods giving access to a measure (ex: get_lifetime() ), are directly returning the value as a double. Dedicated methods allows to access the tkn::tkmeasure to access to units, uncertainties... etc (see Measures and units).

For exemple, for the lifetime, the method get_lifetime_measure() returns the tkmeasure object.