Detailed Description

Calculate elastic scattering spectra in specific detectors of a multidetector array ,.

KVElasticScatter can be used to simulate elastic and inelastic scattering of projectile nuclei in experimental targets, and calculate the energy spectra of the scattered projectile- or target-like nuclei in all detectors on a given trajectory through the array.

See also: KVElasticCountRates

To begin, build the geometry of the multidetector array for a given dataset:

KVMultiDetArray::MakeMultiDetector("name_of_dataset")

KVMultiDetArray::MakeMultiDetector

static KVMultiDetArray * MakeMultiDetector(const Char_t *dataset_name, Int_t run=-1, TString classname="KVMultiDetArray", KVExpDB *db=nullptr)

Definition: KVMultiDetArray.cpp:845

Then initialise a KVElasticScatter with the required run number which will be used to define the default kinematics and the target properties (for energy loss calculations before and after the scattering occurs), e.g.

KVElasticScatter es(31);

KVElasticScatter

Calculate elastic scattering spectra in specific detectors of a multidetector array ,...

Definition: KVElasticScatter.h:190

To define the trajectory for the scattering, give the name of a detector in the array:

es.SetDetector("SI2-111");

Info in <SetDetector>: Using trajectory: CSI-111/SI2-111/SI1-111/

Info

void Info(const char *location, const char *fmt,...)

All particles in the simulation will be scattered into random \(\theta,\phi\) angles corresponding to the direction of these detectors.

Call the Print() method to see the current definitions that will be used by the simulation:

es.Print();
 
Info in <Print>: CALCULATION DETAILS:
Info in <Print>: Entrance channel is: 12C + 1H 11.0 MeV/A
Info in <Print>: Target used is:
Target CH2[193], Target for experiment
Collection name='KVSeqCollection_1269', embedded list class='TList', size=1
 KVMaterial: Polyethylene (CH2)
 Thickness 0.000205319 cm
 Area density 0.000193 g/cm**2
-----------------------------------------------
 Z = 2.66667 atomic mass = 4.66667
 Density = 0.94 g/cm**3
-----------------------------------------------
Info in <Print>: Scattering will be calculated for outgoing PROJECTILE_LIKE
Info in <Print>: We will use the HIGH ENERGY kinematic solutions
Info in <Print>: Particles scattered towards SI2-111: theta:[3.330839,5.169196] phi:[22.297653,46.662894]

If all is correct, run the simulation for a given number of events by calling:

es.CalculateScattering(1000);

Afterwards, you can retrieve the histograms of energy loss in each of the detectors on the chosen trajectory using the label (not the type) of each detector:

es.GetEnergy("SI1")->GetMean();
(double) 120.07858
es.GetEnergy("SI2")->Draw();

etc. etc.

Setting/changing the target nucleus for the kinematics

In the previous example with a carbon beam and polyethylene target, you can see that of the two possible target nuclei in this compound target, it is the protons which are used by default: this has been defined for the systemm corresponding to the chosen run in the database. If you want to change the target nucleus to use for the kinematics, for example to scatter on carbon nuclei, do

es.SetTargetNucleusForScattering("12C");

You can call the Print() method at any moment to check the updated details of the simulation:

es.Print();
 
Info in <Print>: CALCULATION DETAILS:
Info in <Print>: Entrance channel is: 12C + 12C 11.0 MeV/A
...

If the physical target for the chosen run has several layers, by default the scattering will take place in different layers from one event to the next. In this case a different target nucleus can be used for each scattering, depending on the interaction point in the target, if you call:

es.GetTargetNucleusFromTargetLayer(kTRUE);
es.Print()
 
Info in <Print>: CALCULATION DETAILS:
Info in <Print>: Projectile is 12C 11.0 MeV/u; target nucleus depends on scattering layer.

Note: In this case, each layer of the target must be made of a single element, not a compound!

Setting/changing the outgoing nucleus of interest

As you can see above, by default the spectra of energy losses in the different detectors are calculated for the outgoing projectile-like nuclei: to change this, i.e. to calculate for outgoing target-like nuclei, do

es.SetNucleusOfInterest(KV2Body::target_like);

KV2Body::target_like

@ target_like

Definition: KV2Body.h:267

Choice of kinematic solution

As also indicated above, in case there are 2 kinematic solutions for the chosen kinematics and lab angle (detector), by default the high-energy solution corresponding to the most forward centre-of-mass angle solution is used. To change, you can do either

es.SetKinematicSolution(KV2Body::low_E_branch);

KV2Body::low_E_branch

@ low_E_branch

Definition: KV2Body.h:271

to use the solution for backward centre-of-mass angles, or

es.SetKinematicSolution(KV2Body::both_branches);

KV2Body::both_branches

@ both_branches

Definition: KV2Body.h:272

to randomly choose, event by event, one of the two solutions according to the ratio of the corresponding (Rutherford scattering) cross-sections.

Multilayer targets

When multilayer targets are used, the user can restrict the scattering calculation to one specific layer. Energy losses before and after the scattering in the other layers of the target are of course still taken into account. To set the part of the target where scattering takes place use e.g.

es.SetTargetScatteringLayer("Ni")

with the name of the layer you require (this is normally the name of the element making up the layer - see KVTarget for details).

Inelastic scattering

Calculations can also be performed for inelastic scattering e.g. when either the outgoing projectile- or target-like nucleus is left in an excited state (N.B. we still use the Rutherford elastic scattering cross-section for weighting the energy loss distributions). In order to do this, call

es.SetExcitation(4.438);

with the excitation energy after inelastic scattering.

Definition at line 190 of file KVElasticScatter.h.

#include <KVElasticScatter.h>

Inheritance diagram for KVElasticScatter:

[legend]

Public Member Functions
	KVElasticScatter (Int_t run)
	Default constructor. More...

virtual	~ KVElasticScatter ()

void	CalculateScattering (Int_t N)
	Perform scattering 'N' times. More...

TH1F *	GetDepth ()
	Return pointer to histogram of 'depth' of scattering point in target (in mg/cm2) More...

Int_t	GetEbinning (void)
	Returns the number of bins of the GetEnergy histogram. More...

TH1F *	GetEnergy ()
	Return pointer to energy loss histogram for chosen detector (in MeV) More...

TH1F *	GetEnergy (const Char_t *label)
	Energy loss in detector with given 'label' through which scattered particle passes. More...

TH1F *	GetEnergy (Int_t index)

auto	GetKinematics ()

Int_t	GetNDets () const
	Returns the number of detectors crossed by the scattered particle. More...

void	GetTargetNucleusFromTargetLayer (Bool_t yes=kTRUE)

TH1F *	GetTheta ()
	Return pointer to polar angle distribution of scattered particle (in degrees) More...

void	Print () const
	Print details of calculation to be performed. More...

void	SetBeamDirection (const TVector3 &beam_dir)

void	SetDetector (const Char_t *det)

void	SetEbinning (Int_t nbins)

void	SetExcitation (Double_t ex)

void	SetKinematicSolution (KV2Body::kinematic_solution ik)

void	SetNucleusOfInterest (KV2Body::nucleus_of_interest noi)

void	SetOutGoingProjectileLike (const KVNucleus &opl)

void	SetTargetNucleusForScattering (const KVNucleus &tn)

void	SetTargetScatteringLayer (const Char_t *name)

Private Member Functions
virtual void	detect_particle_fill_histograms (KVNucleus *ejectile, double theta, double phi, double xsec)

virtual void	end_of_run ()

virtual std::pair< double, double >	get_random_angles_for_scattering (const KV2Body &scattering_kinematics)

virtual bool	initial_checks_and_reset ()

virtual void	reset_before_new_scattering ()

void	SetRun (Int_t run)

Private Attributes
TList	fAlignedDetectors
	all aligned detectors More...

Double_t	fAtomicDensity
	number of atoms per barn (10^-24 cm2) in target More...

TVector3	fBeamDirection {0, 0, 1}

Int_t	fBinE = 100

TH1F *	fDepth = nullptr

KVDetector *	fDetector = nullptr

KVNameValueList	fDetInd
	detector type-index association More...

Double_t	fExx = 0.0

Bool_t	fGetTargFromLay = false

TObjArray	fHistos
	energy loss histograms for all hit detectors More...

Int_t	fIntLayer = 0

KV2Body *	fKinematics = nullptr

KV2Body::kinematic_solution	fKineSol = KV2Body::kinematic_solution::high_E_branch

Bool_t	fMultiLayer = false

Int_t	fNDets
	number of aligned detectors More...

Double_t	fNtirages

KV2Body::nucleus_of_interest	fNucleusOfInterest = KV2Body::nucleus_of_interest::projectile_like

std::optional< KVNucleus >	fOutgoingPL
	optional different nucleus for outgoing projectile-like More...

KVTarget *	fTarget = nullptr

std::optional< KVNucleus >	fTargetNuc
	optional different target nucleus for scattering More...

TH1F *	fTheta = nullptr

Constructor & Destructor Documentation

◆ KVElasticScatter()

KVElasticScatter::KVElasticScatter ( Int_t run )

Default constructor.

Definition at line 28 of file KVElasticScatter.cpp.

◆ ~ KVElasticScatter()

virtual KVElasticScatter::~ KVElasticScatter ( )

virtual

Member Function Documentation

◆ CalculateScattering()

void KVElasticScatter::CalculateScattering ( Int_t N )

Perform scattering 'N' times.

Definition at line 244 of file KVElasticScatter.cpp.

◆ detect_particle_fill_histograms()

void KVElasticScatter::detect_particle_fill_histograms	(	KVNucleus *	ejectile,
		double	theta,
		double	phi,
		double	xsec
	)

privatevirtual

Reimplemented in KVElasticCountRates.

Definition at line 224 of file KVElasticScatter.cpp.

◆ end_of_run()

virtual void KVElasticScatter::end_of_run ( )

inlineprivatevirtual

Reimplemented in KVElasticCountRates.

Definition at line 220 of file KVElasticScatter.h.

◆ get_random_angles_for_scattering()

std::pair< double, double > KVElasticScatter::get_random_angles_for_scattering ( const KV2Body & scattering_kinematics )

privatevirtual

Reimplemented in KVElasticCountRates.

Definition at line 199 of file KVElasticScatter.cpp.

◆ GetDepth()

TH1F* KVElasticScatter::GetDepth ( )

inline

Return pointer to histogram of 'depth' of scattering point in target (in mg/cm2)

Definition at line 293 of file KVElasticScatter.h.

◆ GetEbinning()

Int_t KVElasticScatter::GetEbinning ( void )

inline

Returns the number of bins of the GetEnergy histogram.

Definition at line 315 of file KVElasticScatter.h.

◆ GetEnergy() [1/3]

TH1F* KVElasticScatter::GetEnergy ( )

inline

Return pointer to energy loss histogram for chosen detector (in MeV)

Definition at line 298 of file KVElasticScatter.h.

◆ GetEnergy() [2/3]

TH1F * KVElasticScatter::GetEnergy ( const Char_t * label )

Energy loss in detector with given 'label' through which scattered particle passes.

Definition at line 409 of file KVElasticScatter.cpp.

◆ GetEnergy() [3/3]

TH1F * KVElasticScatter::GetEnergy ( Int_t index )

Energy loss in any detector through which scattered particle passes.

The index corresponds to the order in which detectors are crossed by the particle, beginning with 0 for the first detector, and ending with (GetNDets()-1)

Definition at line 426 of file KVElasticScatter.cpp.

◆ GetKinematics()

auto KVElasticScatter::GetKinematics ( )

inline

Definition at line 319 of file KVElasticScatter.h.

◆ GetNDets()

Int_t KVElasticScatter::GetNDets ( ) const

inline

Returns the number of detectors crossed by the scattered particle.

Definition at line 310 of file KVElasticScatter.h.

◆ GetTargetNucleusFromTargetLayer()

void KVElasticScatter::GetTargetNucleusFromTargetLayer ( Bool_t yes = kTRUE )

inline

Call with yes=kTRUE if you have a multilayer target with random sampling of interaction point, and you want to calculate the scattering from the different target nucleus in each layer.

Note: this will only work if all layers of the target are single elements (i.e. a single type of nucleus in each layer), not compounds.

Definition at line 275 of file KVElasticScatter.h.

◆ GetTheta()

TH1F* KVElasticScatter::GetTheta ( )

inline

Return pointer to polar angle distribution of scattered particle (in degrees)

Definition at line 303 of file KVElasticScatter.h.

◆ initial_checks_and_reset()

bool KVElasticScatter::initial_checks_and_reset ( )

privatevirtual

Reimplemented in KVElasticCountRates.

Definition at line 177 of file KVElasticScatter.cpp.

◆ Print()

void KVElasticScatter::Print ( void ) const

Print details of calculation to be performed.

Definition at line 441 of file KVElasticScatter.cpp.

◆ reset_before_new_scattering()

virtual void KVElasticScatter::reset_before_new_scattering ( )

inlineprivatevirtual

Reimplemented in KVElasticCountRates.

Definition at line 217 of file KVElasticScatter.h.

◆ SetBeamDirection()

void KVElasticScatter::SetBeamDirection ( const TVector3 & beam_dir )

inline

Use to change alignment of beam (default is {0,0,1})

Definition at line 226 of file KVElasticScatter.h.

◆ SetDetector()

void KVElasticScatter::SetDetector ( const Char_t * det )

Give name of detector towards which elastic scattering will occur.

Note: this does not necessarily mean that the particle will actually arrive in the given detector (it may stop before it), but the aim is to define the trajectory of the particle in the array.

Definition at line 91 of file KVElasticScatter.cpp.

◆ SetEbinning()

void KVElasticScatter::SetEbinning ( Int_t nbins )

Set binning of the GetEnergy histogram Default value is 500

Definition at line 166 of file KVElasticScatter.cpp.

◆ SetExcitation()

void KVElasticScatter::SetExcitation ( Double_t ex )

inline

To simulate inelastic scattering use this method to set the total excitation energy (in MeV).

This value will be used for all subsequent calculations.

Use SetExcitation(0) to return to elastic scattering.

Definition at line 260 of file KVElasticScatter.h.

◆ SetKinematicSolution()

void KVElasticScatter::SetKinematicSolution ( KV2Body::kinematic_solution ik )

inline

Except for projectile-like nuclei in direct kinematics, for almost every other case the kinematics of outgoing nuclei is double-valued, i.e. to each c.m. scattering angle corresponds 2 lab scattering angles, with different energies.

The case with the smallest (most forward) c.m./lab angles is referred to as the 'high energy branch', while the solution at more backward angles has lower energies.

By default we use the high energy branch; you can choose the low energy here.

Definition at line 244 of file KVElasticScatter.h.

◆ SetNucleusOfInterest()

void KVElasticScatter::SetNucleusOfInterest ( KV2Body::nucleus_of_interest noi )

inline

Define the the nucleus of interest in the outgoing channel of the reaction

PROJECTILE + TARGET -> PROJECTILE_LIKE + TARGET_LIKE

Note that the identity of the outgoing PROJECTILE_LIKE can be changed with method SetOutgoingProjectileLike() which will of course change TARGET_LIKE to conserve mass and charge.

Definition at line 232 of file KVElasticScatter.h.

◆ SetOutGoingProjectileLike()

void KVElasticScatter::SetOutGoingProjectileLike ( const KVNucleus & opl )

inline

Definition at line 269 of file KVElasticScatter.h.

◆ SetRun()

void KVElasticScatter::SetRun ( Int_t run )

private

Set beam, detector parameters, target, etc. for run

The default reaction kinematics is that of the KVDBSystem associated to the run.

The default scattering position in the target is random.

Definition at line 63 of file KVElasticScatter.cpp.

◆ SetTargetNucleusForScattering()

void KVElasticScatter::SetTargetNucleusForScattering ( const KVNucleus & tn )

inline

call this method to change the default target nucleus of the kinematics for the run

Definition at line 284 of file KVElasticScatter.h.

◆ SetTargetScatteringLayer()

void KVElasticScatter::SetTargetScatteringLayer ( const Char_t * name )

For multilayer targets, use this method to choose in which layer the scattering will take place.

If name="", reset any previous choice so that scattering can take place in any layer

Definition at line 141 of file KVElasticScatter.cpp.

Member Data Documentation

◆ fAlignedDetectors

TList KVElasticScatter::fAlignedDetectors

private

all aligned detectors

Definition at line 197 of file KVElasticScatter.h.

◆ fAtomicDensity

Double_t KVElasticScatter::fAtomicDensity

private

number of atoms per barn (10^-24 cm2) in target

Definition at line 215 of file KVElasticScatter.h.

◆ fBeamDirection

TVector3 KVElasticScatter::fBeamDirection {0, 0, 1}

private

Definition at line 202 of file KVElasticScatter.h.

◆ fBinE

Int_t KVElasticScatter::fBinE = 100

private

Definition at line 194 of file KVElasticScatter.h.

◆ fDepth

TH1F* KVElasticScatter::fDepth = nullptr

private

Definition at line 192 of file KVElasticScatter.h.

◆ fDetector

KVDetector* KVElasticScatter::fDetector = nullptr

private

Definition at line 196 of file KVElasticScatter.h.

◆ fDetInd

KVNameValueList KVElasticScatter::fDetInd

private

detector type-index association

Definition at line 205 of file KVElasticScatter.h.

◆ fExx

Double_t KVElasticScatter::fExx = 0.0

private

Definition at line 206 of file KVElasticScatter.h.

◆ fGetTargFromLay

Bool_t KVElasticScatter::fGetTargFromLay = false

private

Definition at line 201 of file KVElasticScatter.h.

◆ fHistos

TObjArray KVElasticScatter::fHistos

private

energy loss histograms for all hit detectors

Definition at line 204 of file KVElasticScatter.h.

◆ fIntLayer

Int_t KVElasticScatter::fIntLayer = 0

private

Definition at line 203 of file KVElasticScatter.h.

◆ fKinematics

KV2Body* KVElasticScatter::fKinematics = nullptr

private

Definition at line 195 of file KVElasticScatter.h.

◆ fKineSol

KV2Body::kinematic_solution KVElasticScatter::fKineSol = KV2Body::kinematic_solution::high_E_branch

private

Definition at line 211 of file KVElasticScatter.h.

◆ fMultiLayer

Bool_t KVElasticScatter::fMultiLayer = false

private

Definition at line 200 of file KVElasticScatter.h.

◆ fNDets

Int_t KVElasticScatter::fNDets

private

number of aligned detectors

Definition at line 198 of file KVElasticScatter.h.

◆ fNtirages

Double_t KVElasticScatter::fNtirages

private

Definition at line 214 of file KVElasticScatter.h.

◆ fNucleusOfInterest

KV2Body::nucleus_of_interest KVElasticScatter::fNucleusOfInterest = KV2Body::nucleus_of_interest::projectile_like

private

Definition at line 210 of file KVElasticScatter.h.

◆ fOutgoingPL

std::optional<KVNucleus> KVElasticScatter::fOutgoingPL

private

optional different nucleus for outgoing projectile-like

Definition at line 207 of file KVElasticScatter.h.

◆ fTarget

KVTarget* KVElasticScatter::fTarget = nullptr

private

Definition at line 199 of file KVElasticScatter.h.

◆ fTargetNuc

std::optional<KVNucleus> KVElasticScatter::fTargetNuc

private

optional different target nucleus for scattering

Definition at line 208 of file KVElasticScatter.h.

◆ fTheta

TH1F* KVElasticScatter::fTheta = nullptr

private

Definition at line 193 of file KVElasticScatter.h.

Detailed Description

Setting/changing the target nucleus for the kinematics

Setting/changing the outgoing nucleus of interest

Choice of kinematic solution

Multilayer targets

Inelastic scattering

Public Member Functions

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ KVElasticScatter()

◆ ~ KVElasticScatter()

Member Function Documentation

◆ CalculateScattering()

◆ detect_particle_fill_histograms()

◆ end_of_run()

◆ get_random_angles_for_scattering()

◆ GetDepth()

◆ GetEbinning()

◆ GetEnergy() [1/3]

◆ GetEnergy() [2/3]

◆ GetEnergy() [3/3]

◆ GetKinematics()

◆ GetNDets()

◆ GetTargetNucleusFromTargetLayer()

◆ GetTheta()

◆ initial_checks_and_reset()

◆ Print()

◆ reset_before_new_scattering()

◆ SetBeamDirection()

◆ SetDetector()

◆ SetEbinning()

◆ SetExcitation()

◆ SetKinematicSolution()

◆ SetNucleusOfInterest()

◆ SetOutGoingProjectileLike()

◆ SetRun()

◆ SetTargetNucleusForScattering()

◆ SetTargetScatteringLayer()

Member Data Documentation

◆ fAlignedDetectors

◆ fAtomicDensity

◆ fBeamDirection

◆ fBinE

◆ fDepth

◆ fDetector

◆ fDetInd

◆ fExx

◆ fGetTargFromLay

◆ fHistos

◆ fIntLayer

◆ fKinematics

◆ fKineSol

◆ fMultiLayer

◆ fNDets

◆ fNtirages

◆ fNucleusOfInterest

◆ fOutgoingPL

◆ fTarget

◆ fTargetNuc

◆ fTheta