BeamEnergies Namespace Reference

The beam's energy at each anode strip, from the simulated unreacted beam. More...

Functions
TString	SimPath ()
	Path to the dataset's beam simulation file.
Bool_t	Profile (const TString &path, Double_t *dE, Double_t &e_strip0)
	Read the per-strip energy loss profile from a beam simulation.
Double_t	LabAtStrip (const Double_t *dE, Double_t e_strip0, Int_t reac)
	Lab energy entering a given strip.
Double_t	CmFraction ()
	Centre-of-mass energy fraction for this dataset's reaction.

Detailed Description

The beam's energy at each anode strip, from the simulated unreacted beam.

The simulation's stopping model (SRIM, catima, or mean of SRIM and catima) is chosen so that the beam's Bragg peak falls in the strip where the data puts it. Its per-strip level can therefore differ from the data's by several percent; what it fixes is where along the detector the beam is, which is what the energy at each strip depends on. So each strip's centre-of-mass energy is the simulation's own rather than a nominal dE/dx table's, and its uncertainty is that of the peak position, about half a strip.

The energy entering strip 0 is what came through the entrance window minus what the upstream dead layer of gas took. MUSIC has 3.6 cm of gas ahead of the first anode strip so starting the bookkeeping at the window instead puts every strip a full strip and a half too high.

Shared by the cross-section calculation, which reports at these energies, and by talys-xs, which computes over them.

Function Documentation

CmFraction()

Double_t BeamEnergies::CmFraction

(

)

Centre-of-mass energy fraction for this dataset's reaction.

Returns

A_t / (A_b + A_t), from the dataset's configuration. Multiply a lab energy by this to get the centre-of-mass energy.

Definition at line 63 of file BeamEnergies.cpp.

Referenced by main().

LabAtStrip()

Double_t BeamEnergies::LabAtStrip	(	const Double_t *	dE,
		Double_t	e_strip0,
		Int_t	reac )

Lab energy entering a given strip.

What entered strip 0, less the mean loss of every strip before reac.

Parameters

dE	Per-strip losses from Profile().
e_strip0	Energy entering strip 0, from Profile().
reac	Strip index, 0 to 17.

Returns

The lab-frame energy entering that strip, in MeV.

Definition at line 56 of file BeamEnergies.cpp.

Referenced by main().

Profile()

Bool_t BeamEnergies::Profile	(	const TString &	path,
		Double_t *	dE,
		Double_t &	e_strip0 )

Read the per-strip energy loss profile from a beam simulation.

Parameters

	path	Beam simulation file, normally from SimPath().
[out]	dE	Mean energy deposited in each of the 18 strips, in MeV. Must point at 18 elements.
[out]	e_strip0	Lab energy entering strip 0, in MeV — already net of the upstream gas dead layer.

Returns

kFALSE if the file or the trees inside it are missing, in which case the outputs are not meaningful.

Definition at line 16 of file BeamEnergies.cpp.

Referenced by main().

SimPath()

TString BeamEnergies::SimPath

(

)

Path to the dataset's beam simulation file.

Returns

CROSS_SECTION_CONFIG.BEAM_SIM_FILE, resolved under sim_root_files.

Definition at line 11 of file BeamEnergies.cpp.

Referenced by main().