///////////////////////////////////////////////////////////////////////////////
// //
// Time Projection Chamber version 3 -- detailed TPC and slow simulation //
// //
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// //
// //
///////////////////////////////////////////////////////////////////////////////
#include
#include
#include "AliTPCv3.h"
#include "AliRun.h"
#include "AliConst.h"
ClassImp(AliTPCv3)
//_____________________________________________________________________________
AliTPCv3::AliTPCv3(const char *name, const char *title) :
AliTPC(name, title)
{
//
// Standard constructor for Time Projection Chamber version 2
//
SetBufferSize(128000);
}
//_____________________________________________________________________________
void AliTPCv3::CreateGeometry()
{
//
// Create the geometry of Time Projection Chamber version 3
//
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Int_t *idtmed = fIdtmed->GetArray()-399;
Float_t tana, rlsl, wlsl, rssl, rlsu, wssl, wlsu,
rssu, wssu, alpha, x, y, sec_thick;
Float_t x1, z0, z1, x2, theta1, theta2, theta3, dm[21];
Int_t il, iu;
Float_t z_side;
Int_t idrotm[100];
Float_t x0l, x0u;
Int_t idr;
//Float_t thl, thu;
Float_t opl, opu, phi1, phi2, phi3;
// ----------------------------------------------------
// FIELD CAGE WITH ENDCAPS - CARBON FIBER
// THIS IS ALSO A TPC MOTHER VOLUME
// ----------------------------------------------------
dm[0] = 76.;
dm[1] = 278.;
dm[2] = 275.;
gMC->Gsvolu("TPC ", "TUBE", idtmed[407], dm, 3);
// -------------------------------------------------------
// drift gas Ne/CO2 (90/10 volume) - sensitive
// field cage thickness = 0.52% X0
// ----------------------------------------------------
dm[0] = 76.+0.09776;
dm[1] = 257.;
dm[2] = 250.;
gMC->Gsvolu("TGAS", "TUBE", idtmed[403], dm, 3);
// ------------------------------------------------------
// "side" gas volume (the same as drift gas)
// here the readout chambers are positioned
// ------------------------------------------------------
dm[2] = 0.5*(275.-250.);
z_side = dm[2];
gMC->Gsvolu("TPSG", "TUBE", idtmed[401], dm, 3);
// ------------------------------------------------------
// HV midplane - 20 microns of mylar
// -----------------------------------------------------
dm[2] = .001;
gMC->Gsvolu("TPHV", "TUBE", idtmed[405], dm, 3);
// ====================================================
// lower and upper readout chambers
// ====================================================
// sectros opening angles in degrees
// ---------------------------------------------------
opl = 30.;
opu = 15.;
//thl = TMath::Tan(opl * .5 * kDegrad);
//thu = TMath::Tan(opu * .5 * kDegrad);
// ---------------------------------------------------
// S and L-sectors radii
// ---------------------------------------------------
rssl = 88.;
rssu = 136.;
rlsl = 142.;
rlsu = 250.;
// --------------------------------------------------
// Sectors widths
// --------------------------------------------------
wssl = 46.5;
wssu = 72.2;
wlsl = 37.;
wlsu = 65.4;
// ---------------------------------------------------
// Sector thickness 25% of X0 (Al)
// ---------------------------------------------------
sec_thick = 2.225;
// ---------------------------------------------------
// S-sectors readout chambers (lower sectors)
// ---------------------------------------------------
dm[0] = wssl * .5;
dm[1] = wssu * .5;
dm[2] = sec_thick * .5;
dm[3] = (rssu - rssl) * .5;
x0l = rssl + dm[3];
gMC->Gsvolu("TRCS", "TRD1", idtmed[399], dm, 4);
// ---------------------------------------------------
// L-sectors readout chambers (upper sectors)
// ---------------------------------------------------
dm[0] = wlsl * .5;
dm[1] = wlsu * .5;
dm[2] = sec_thick * .5;
dm[3] = (rlsu - rlsl) * .5;
x0u = rlsl + dm[3];
gMC->Gsvolu("TRCL", "TRD1", idtmed[399], dm, 4);
// ----------------------------------------------------
// positioning of the S-sector readout chambers
// rotation matices 1-12
// ----------------------------------------------------
z1 = -z_side + sec_thick * .5;
for (il = 1; il <= 12; ++il) {
phi1 = (il - 1) * opl + 270.;
if (phi1 > 360.) {
phi1 += -360.;
}
theta1 = 90.;
phi2 = 90.;
theta2 = 180.;
phi3 = (il - 1) * opl;
theta3 = 90.;
idr = il;
alpha = (il - 1) * opl * kDegrad;
x = x0l * TMath::Cos(alpha);
y = x0l * TMath::Sin(alpha);
AliMatrix(idrotm[idr], theta1, phi1, theta2, phi2, theta3, phi3);
gMC->Gspos("TRCS", il, "TPSG", x, y, z1, idrotm[idr], "ONLY");
}
// ----------------------------------------------------
// positioning of the L-sector readout chambers
// rotation matices 13-36
// ----------------------------------------------------
for (iu = 1; iu <= 24; ++iu) {
phi1 = (iu - 1) * opu + 270.;
if (phi1 > 360.) {
phi1 += -360.;
}
theta1 = 90.;
phi2 = 90.;
theta2 = 180.;
phi3 = (iu - 1) * opu;
theta3 = 90.;
idr = iu + 12;
AliMatrix(idrotm[idr], theta1, phi1, theta2, phi2, theta3, phi3);
alpha = (iu - 1) * opu * kDegrad;
x = x0u * TMath::Cos(alpha);
y = x0u * TMath::Sin(alpha);
gMC->Gspos("TRCL", iu, "TPSG", x, y, z1, idrotm[idr], "ONLY");
}
// --------------------------------------------------------
// Spoke wheel structures
// --------------------------------------------------------
gMC->Gsvolu("TSWS", "TUBE", idtmed[399], dm, 0);
z0 = -z_side + 2.;
dm[0] = 82.;
dm[1] = 86.;
dm[2] = 1.;
gMC->Gsposp("TSWS", 1, "TPSG", 0, 0, z0, 0, "ONLY", dm, 3);
dm[0] = 253.;
dm[1] = 257.;
gMC->Gsposp("TSWS", 2, "TPSG", 0, 0, z0, 0, "ONLY", dm, 3);
dm[0] = 140.9;
dm[1] = 141.9;
gMC->Gsposp("TSWS", 3, "TPSG", 0, 0, z0, 0, "ONLY", dm, 3);
// -------------------------------------------------------
// this volumes are to avoid overlaping
// -------------------------------------------------------
z0 = 253.;
dm[0] = 76.;
dm[1] = 76.+0.09776;
gMC->Gsposp("TSWS", 4, "TPC ", 0, 0, z0, 0, "ONLY", dm, 3);
gMC->Gsposp("TSWS", 5, "TPC ", 0, 0, -z0,0, "ONLY", dm, 3);
z0 += 21.;
gMC->Gsposp("TSWS", 6, "TPC ", 0, 0, z0, 0, "ONLY", dm, 3);
gMC->Gsposp("TSWS", 7, "TPC ", 0, 0, -z0, 0, "ONLY", dm, 3);
dm[0] = 257.;
dm[1] = 257.+0.09776;
dm[2] = 11.5;
z0 = 263.5;
gMC->Gsposp("TSWS", 8, "TPC ", 0, 0, z0, 0, "ONLY", dm, 3);
gMC->Gsposp("TSWS", 9, "TPC ", 0, 0, -z0, 0, "ONLY", dm, 3);
// ==========================================================
// wheels
// ==========================================================
// ----------------------------------------------------------
// Large wheel -> positioned in the TPC
// ----------------------------------------------------------
dm[0] = 257.+0.09776;
dm[1] = 278.;
dm[2] = 11.5;
gMC->Gsvolu("TPW1", "TUBE", idtmed[399], dm, 3);
dm[0] = 259.;
dm[1] = 278.;
dm[2] = 9.5;
gMC->Gsvolu("TPW2", "TUBE", idtmed[498], dm, 3);
gMC->Gspos("TPW2", 1, "TPW1", 0, 0, 0, 0, "ONLY");
gMC->Gspos("TPW1", 1, "TPC ", 0, 0, z0, 0, "ONLY");
gMC->Gspos("TPW1", 2, "TPC ", 0, 0, -z0, 0, "ONLY");
// -----------------------------------------------------------
// Small wheel -> positioned in the TPSG
// -----------------------------------------------------------
dm[0] = 76.+0.09776;
dm[1] = 82.;
dm[2] = 11.5;
gMC->Gsvolu("TPW3", "TUBE", idtmed[399], dm, 3);
dm[0] = 76.+0.09776;
dm[1] = 80.;
dm[2] = 9.5;
gMC->Gsvolu("TPW4", "TUBE", idtmed[401], dm, 3);
gMC->Gspos("TPW4", 1, "TPW3", 0, 0, 0, 0, "ONLY");
z0 = 1.;
gMC->Gspos("TPW3", 1, "TPSG", 0, 0, z0, 0, "ONLY");
// ---------------------------------------------------------
// spokes, inner and outer, also the inner ring
// ---------------------------------------------------------
dm[0] = 0.5*(135.9-82.1);
dm[1] = 3.;
dm[2] = 2.;
x1 = dm[0] + 82.;
gMC->Gsvolu("TSPI", "BOX ", idtmed[399], dm, 3);
dm[1] = 2.;
dm[2] = 1.;
gMC->Gsvolu("TSP1", "BOX ", idtmed[498], dm, 3);
gMC->Gspos("TSP1", 1, "TSPI", 0, 0, 0, 0, "ONLY");
dm[0] = 0.5*(256.9-142.1);
dm[1] = 3.;
dm[2] = 2.;
x2 = dm[0] + 142.;
gMC->Gsvolu("TSPO", "BOX ", idtmed[399], dm, 3);
dm[1] = 2.;
dm[2] = 1.;
gMC->Gsvolu("TSP2", "BOX ", idtmed[498], dm, 3);
gMC->Gspos("TSP2", 1, "TSPO", 0, 0, 0, 0, "ONLY");
// --------------------------------------------------------
dm[0] = 136.;
dm[1] = 142.;
dm[2] = 2.;
gMC->Gsvolu("TSWH", "TUBE", idtmed[399], dm, 3);
dm[0] = 137.;
dm[1] = 141.;
dm[2] = 1.;
gMC->Gsvolu("TSW1", "TUBE", idtmed[498], dm, 3);
gMC->Gspos("TSW1", 1, "TSWH", 0, 0, 0, 0, "ONLY");
z0 = z_side - .16168 - 2.;
// --------------------------------------------------------
gMC->Gspos("TSWH", 1, "TPSG", 0, 0, z0, 0, "ONLY");
// -------------------------------------------------------
// posiioning of the inner spokes
// -------------------------------------------------------
for (il = 1; il <= 6; ++il) {
phi1 = opl * .5 + (il - 1) * 2. * opl;
theta1 = 90.;
phi2 = opl * .5 + 90. + (il - 1) * 2. * opl;
if (phi2 > 360.) {
phi2 += -360.;
}
theta2 = 90.;
phi3 = 0.;
theta3 = 0.;
alpha = phi1 * kDegrad;
x = x1 * TMath::Cos(alpha);
y = x1 * TMath::Sin(alpha);
idr = il + 36;
AliMatrix(idrotm[idr], theta1, phi1, theta2, phi2, theta3, phi3);
gMC->Gspos("TSPI", il, "TPSG", x, y, z0, idrotm[idr], "ONLY");
}
for (iu = 1; iu <= 12; ++iu) {
phi1 = opu * .5 + (iu - 1) * 2. * opu;
theta1 = 90.;
phi2 = opu * .5 + 90. + (iu - 1) * 2. * opu;
if (phi2 > 360.) {
phi2 += -360.;
}
theta2 = 90.;
phi3 = 0.;
theta3 = 0.;
alpha = phi1 * kDegrad;
x = x2 * TMath::Cos(alpha);
y = x2 * TMath::Sin(alpha);
idr = iu + 42;
AliMatrix(idrotm[idr], theta1, phi1, theta2, phi2, theta3, phi3);
gMC->Gspos("TSPO", iu, "TPSG", x, y, z0, idrotm[idr], "ONLY");
}
// --------------------------------------------------------
// endcap cover (C, 0.86% X0)
// --------------------------------------------------------
dm[0] = 76.+0.09776;
dm[1] = 257.;
dm[2] = 0.16168*0.5;
gMC->Gsvolu("TCOV", "TUBE", idtmed[407], dm, 3);
z0 = z_side - dm[2];
gMC->Gspos("TCOV", 1, "TPSG", 0, 0, z0, 0, "ONLY");
// --------------------------------------------------------
// put the readout chambers into the TPC
// --------------------------------------------------------
theta1 = 90.;
phi1 = 0.;
theta2 = 90.;
phi2 = 270.;
theta3 = 180.;
phi3 = 0.;
AliMatrix(idrotm[55], theta1, phi1, theta2, phi2, theta3, phi3);
z0 = z_side + 250.;
gMC->Gspos("TPSG", 1, "TPC ", 0, 0, z0, 0, "ONLY");
gMC->Gspos("TPSG", 2, "TPC ", 0, 0, -z0, idrotm[55], "ONLY");
// ---------------------------------------------------------
// outer gas insulation (CO2)
// ---------------------------------------------------------
dm[0] = 257.+0.09776;
dm[1] = 278.-0.25004;
dm[2] = 275.-23.;
gMC->Gsvolu("TPOI", "TUBE", idtmed[406], dm, 3);
gMC->Gspos("TPHV", 1, "TGAS", 0, 0, 0, 0, "ONLY");
gMC->Gspos("TGAS", 1, "TPC ", 0, 0, 0, 0, "ONLY");
gMC->Gspos("TPOI", 1, "TPC ", 0, 0, 0, 0, "ONLY");
gMC->Gspos("TPC ", 1, "ALIC", 0, 0, 0, 0, "ONLY");
// ======================================================
// all volumes below are positioned in ALIC
// ======================================================
// ------------------------------------------------------
// the last parts of the smaller wheel (TSWS)
// ------------------------------------------------------
dm[0] = 74.;
dm[1] = 76.;
dm[2] = 1.;
z0 = 253.;
gMC->Gsposp("TSWS", 10, "TPC ", 0, 0, z0, 0, "ONLY", dm, 3);
gMC->Gsposp("TSWS", 11, "TPC ", 0, 0, -z0, 0, "ONLY", dm, 3);
dm[0] = 70.;
z0 += 21.;
gMC->Gsposp("TSWS", 12, "TPC ", 0, 0, z0, 0, "ONLY", dm, 3);
gMC->Gsposp("TSWS", 13, "TPC ", 0, 0, -z0, 0, "ONLY", dm, 3);
// ----------------------------------------------------
// Inner vessel (PCON)
// This volume is to be positioned directly in ALIC
// ----------------------------------------------------
dm[0] = 0.;
dm[1] = 360.;
dm[2] = 4.;
dm[3] = -250.;
dm[4] = 75.;
dm[5] = 76.;
dm[6] = -64.5;
dm[7] = 50.;
dm[8] = 76.;
dm[9] = 64.5;
dm[10] = 50.;
dm[11] = 76.;
dm[12] = 250.;
dm[13] = 75.;
dm[14] = 76.;
gMC->Gsvolu("TPIV", "PCON", idtmed[407], dm, 15);
// --------------------------------------------------------
// fill the inner vessel with CO2, (HV kDegrader)
// cone parts have different thickness
// than the central barrel, according to the TP
// --------------------------------------------------------
tana = 75./185.5;
dm[0] = 0.;
dm[1] = 360.;
dm[2] = 6.;
dm[3] = -(250.-0.2162);
dm[4] = (185.5-0.2126)*tana+0.2126;
dm[5] = 76-0.001;
dm[6] = -64.5;
dm[7] = 50.+0.2162;
dm[8] = 76-0.001;
dm[9] = -64.5;
dm[10] = 50+0.05076;
dm[11] = 76-0.001;
dm[12] = 64.5;
dm[13] = 50+0.05076;
dm[14] = 76-0.001;
dm[15] = 64.5;
dm[16] = 50.+0.2162;
dm[17] = 76-0.001;
dm[18] = (250.-0.2162);
dm[19] = (185.5-0.2126)*tana+0.2126;
dm[20] = 76-0.001;
gMC->Gsvolu("TPVD", "PCON", idtmed[406], dm, 21);
gMC->Gspos("TPVD", 1, "TPIV", 0, 0, 0, 0, "ONLY");
gMC->Gspos("TPIV", 1, "ALIC", 0, 0, 0, 0, "ONLY");
// ---------------------------------------------------
// volumes ordering
// ---------------------------------------------------
gMC->Gsord("TPSG", 6);
}
//_____________________________________________________________________________
void AliTPCv3::DrawDetector()
{
//
// Draw a shaded view of the Time Projection Chamber version 1
//
// Set everything unseen
gMC->Gsatt("*", "seen", -1);
//
// Set ALIC mother transparent
gMC->Gsatt("ALIC","SEEN",0);
//
// Set the volumes visible
gMC->Gsatt("TPC","SEEN",0);
gMC->Gsatt("TGAS","SEEN",0);
gMC->Gsatt("TPSG","SEEN",0);
gMC->Gsatt("TPHV","SEEN",1);
gMC->Gsatt("TRCS","SEEN",1);
gMC->Gsatt("TRCL","SEEN",1);
gMC->Gsatt("TSWS","SEEN",1);
gMC->Gsatt("TPW1","SEEN",1);
gMC->Gsatt("TPW2","SEEN",1);
gMC->Gsatt("TPW3","SEEN",1);
gMC->Gsatt("TPW4","SEEN",1);
gMC->Gsatt("TSPI","SEEN",1);
gMC->Gsatt("TSP1","SEEN",0);
gMC->Gsatt("TSPO","SEEN",1);
gMC->Gsatt("TSP2","SEEN",0);
gMC->Gsatt("TSWH","SEEN",1);
gMC->Gsatt("TSW1","SEEN",1);
gMC->Gsatt("TPOI","SEEN",1);
gMC->Gsatt("TPIV","SEEN",1);
gMC->Gsatt("TPVD","SEEN",1);
//
gMC->Gdopt("hide", "on");
gMC->Gdopt("shad", "on");
gMC->Gsatt("*", "fill", 7);
gMC->SetClipBox(".");
gMC->SetClipBox("*", 0, 1000, -1000, 1000, -1000, 1000);
gMC->DefaultRange();
gMC->Gdraw("alic", 40, 30, 0, 12, 9.5, .025, .025);
gMC->Gdhead(1111, "Time Projection Chamber");
gMC->Gdman(18, 4, "MAN");
gMC->Gdopt("hide","off");
}
//_____________________________________________________________________________
void AliTPCv3::CreateMaterials()
{
//
// Define materials for version 2 of the Time Projection Chamber
//
//
// Increase maximum number of steps
gMC->SetMaxNStep(30000);
//
AliTPC::CreateMaterials();
}
//_____________________________________________________________________________
void AliTPCv3::Init()
{
//
// Initialises version 3 of the TPC after that it has been built
//
Int_t *idtmed = fIdtmed->GetArray()-399;
AliTPC::Init();
fIdSens1=gMC->VolId("TGAS"); // drift gas as a sensitive volume
gMC->SetMaxNStep(30000); // max. number of steps increased
gMC->Gstpar(idtmed[403],"LOSS",5);
printf("*** TPC version 3 initialized ***\n");
printf("Maximum number of steps = %d\n",gMC->GetMaxNStep());
//
}
//_____________________________________________________________________________
void AliTPCv3::StepManager()
{
//
// Called for every step in the Time Projection Chamber
//
//
// parameters used for the energy loss calculations
//
const Float_t prim = 14.35; // number of primary collisions per 1 cm
const Float_t poti = 20.77e-9; // first ionization potential for Ne/CO2
const Float_t w_ion = 35.97e-9; // energy for the ion-electron pair creation
const Float_t big = 1.e10;
Int_t id,copy;
TLorentzVector pos;
Float_t hits[4];
Int_t vol[2];
TClonesArray &lhits = *fHits;
vol[1]=0;
vol[0]=0;
//
gMC->SetMaxStep(big);
if(!gMC->IsTrackAlive()) return; // particle has disappeared
Float_t charge = gMC->TrackCharge();
if(TMath::Abs(charge)<=0.) return; // take only charged particles
id=gMC->CurrentVolID(copy);
// Check the sensitive volume
if (id != fIdSens1) return;
//
// charged particle is in the sensitive volume
//
if(gMC->TrackStep() > 0) {
Int_t nel = (Int_t)(((gMC->Edep())-poti)/w_ion) + 1;
nel=TMath::Min(nel,300); // 300 electrons corresponds to 10 keV
gMC->TrackPosition(pos);
hits[0]=pos[0];
hits[1]=pos[1];
hits[2]=pos[2];
//
// check the selected side of the TPC
//
if(fSide && fSide*hits[2]<=0.) return;
hits[3]=(Float_t)nel;
// Add this hit
new(lhits[fNhits++]) AliTPChit(fIshunt,gAlice->CurrentTrack(),vol,hits);
}
// Stemax calculation for the next step
Float_t pp;
TLorentzVector mom;
gMC->TrackMomentum(mom);
Float_t ptot=mom.Rho();
Float_t beta_gamma = ptot/gMC->TrackMass();
if(gMC->TrackPid() <= 3 && ptot > 0.002)
{
pp = prim*1.58; // electrons above 20 MeV/c are on the plateau!
}
else
{
pp=prim*BetheBloch(beta_gamma);
if(TMath::Abs(charge) > 1.) pp *= (charge*charge);
}
Float_t random[1];
gMC->Rndm(random,1); // good, old GRNDM from Geant3
Double_t rnd = (Double_t)random[0];
gMC->SetMaxStep(-TMath::Log(rnd)/pp);
}
//_____________________________________________________________________________
Float_t AliTPCv3::BetheBloch(Float_t bg)
{
//
// Bethe-Bloch energy loss formula
//
const Double_t p1=0.76176e-1;
const Double_t p2=10.632;
const Double_t p3=0.13279e-4;
const Double_t p4=1.8631;
const Double_t p5=1.9479;
Double_t dbg = (Double_t) bg;
Double_t beta = dbg/TMath::Sqrt(1.+dbg*dbg);
Double_t aa = TMath::Power(beta,p4);
Double_t bb = TMath::Power(1./dbg,p5);
bb=TMath::Log(p3+bb);
return ((Float_t)((p2-aa-bb)*p1/aa));
}