Commit d630b01e authored by Whitney Armstrong's avatar Whitney Armstrong
Browse files

modified: part2/adding_detectors.md

parent f4847131
......@@ -2,20 +2,6 @@
title: 'Tutorial Part 2: Modifying and Adding Detectors '
---
* [Introduction](#introduction)
* [How to build a detector from scratch](#how-to-build-a-detector-from-scratch)
+ [Compiling a new detector](#compiling-a-new-detector)
+ [Building the geometry](#building-the-geometry)
- [Compact detector description entry element](#compact-detector-description-entry-element)
- [Geometry Construction](#geometry-construction)
* [XML Parsing Tip : Provide good default values](#xml-parsing-tip--provide-good-default-values)
- [Critical parts of build_detector](#critical-parts-of-build_detector)
* [The Readout and Bit Fields](#the-readout-and-bit-fields)
* [Simple Reconstruction Overview of scripts](#simple-reconstruction-overview-of-scripts)
+ [Dependencies](#dependencies)
+ [Running the scripts](#running-the-scripts)
+ [To Do](#to-do)
## Setup
Note all these commands assume you are in an `eic-shell` singularity session.
......@@ -315,4 +301,157 @@ And have a look at the detector part of the compact file.
Here you see a different strategy: build a module, then build layers constructed from the module.
Here is the detector constructor function
```cpp
static Ref_t create_detector(Detector& description, xml_h e, SensitiveDetector sens) {
typedef vector<PlacedVolume> Placements;
xml_det_t x_det = e;
Material vacuum = description.vacuum();
int det_id = x_det.id();
string det_name = x_det.nameStr();
bool reflect = x_det.reflect(false);
DetElement sdet(det_name, det_id);
Assembly assembly(det_name);
Volume motherVol = description.pickMotherVolume(sdet);
int m_id = 0, c_id = 0, n_sensor = 0;
map<string, Volume> modules;
map<string, Placements> sensitives;
PlacedVolume pv;
assembly.setVisAttributes(description.invisible());
sens.setType("tracker");
// Loop over and build modules
for (xml_coll_t mi(x_det, _U(module)); mi; ++mi, ++m_id) {
xml_comp_t x_mod = mi;
string m_nam = x_mod.nameStr();
xml_comp_t trd = x_mod.trd();
double posY;
double x1 = trd.x1();
double x2 = trd.x2();
double z = trd.z();
double y1, y2, total_thickness = 0.;
xml_coll_t ci(x_mod, _U(module_component));
for (ci.reset(), total_thickness = 0.0; ci; ++ci)
total_thickness += xml_comp_t(ci).thickness();
y1 = y2 = total_thickness / 2;
Volume m_volume(m_nam, Trapezoid(x1, x2, y1, y2, z), vacuum);
m_volume.setVisAttributes(description.visAttributes(x_mod.visStr()));
for (ci.reset(), n_sensor = 1, c_id = 0, posY = -y1; ci; ++ci, ++c_id) {
xml_comp_t c = ci;
double c_thick = c.thickness();
auto comp_x1 = getAttrOrDefault(c, _Unicode(x1), x1);
auto comp_x2 = getAttrOrDefault(c, _Unicode(x2), x2);
auto comp_height = getAttrOrDefault(c, _Unicode(height), z);
Material c_mat = description.material(c.materialStr());
string c_name = _toString(c_id, "component%d");
Volume c_vol(c_name, Trapezoid(comp_x1, comp_x2, c_thick / 2e0, c_thick / 2e0, comp_height), c_mat);
// use the module vis attributes if not set for component.
auto comp_vis = x_mod.visStr();
if(( c.visStr().size() >0 ) ) {
comp_vis = c.visStr();
}
c_vol.setVisAttributes(description.visAttributes(comp_vis));
pv = m_volume.placeVolume(c_vol, Position(0, posY + c_thick / 2, 0));
if (c.isSensitive()) {
sdet.check(n_sensor > 2, "SiTrackerEndcap2::fromCompact: " + c_name + " Max of 2 modules allowed!");
pv.addPhysVolID("sensor", n_sensor);
c_vol.setSensitiveDetector(sens);
sensitives[m_nam].push_back(pv);
++n_sensor;
}
posY += c_thick;
}
// Modules are stored here
modules[m_nam] = m_volume;
}
// Construct each layer
for (xml_coll_t li(x_det, _U(layer)); li; ++li) {
xml_comp_t x_layer(li);
int l_id = x_layer.id();
int mod_num = 1;
for (xml_coll_t ri(x_layer, _U(ring)); ri; ++ri) {
xml_comp_t x_ring = ri;
double r = x_ring.r();
double phi0 = x_ring.phi0(0);
double zstart = x_ring.zstart();
double dz = x_ring.dz(0);
int nmodules = x_ring.nmodules();
string m_nam = x_ring.moduleStr();
Volume m_vol = modules[m_nam];
double iphi = 2 * M_PI / nmodules;
double phi = phi0;
Placements& sensVols = sensitives[m_nam];
for (int k = 0; k < nmodules; ++k) {
string m_base = _toString(l_id, "layer%d") + _toString(mod_num, "_module%d");
double x = -r * std::cos(phi);
double y = -r * std::sin(phi);
DetElement module(sdet, m_base + "_pos", det_id);
pv = assembly.placeVolume(m_vol,
Transform3D(RotationZYX(0, -M_PI / 2 - phi, -M_PI / 2), Position(x, y, zstart + dz)));
pv.addPhysVolID("barrel", 1).addPhysVolID("layer", l_id).addPhysVolID("module", mod_num);
module.setPlacement(pv);
for (size_t ic = 0; ic < sensVols.size(); ++ic) {
PlacedVolume sens_pv = sensVols[ic];
DetElement comp_elt(module, sens_pv.volume().name(), mod_num);
comp_elt.setPlacement(sens_pv);
}
if (reflect) {
pv = assembly.placeVolume(
m_vol, Transform3D(RotationZYX(M_PI, -M_PI / 2 - phi, -M_PI / 2), Position(x, y, -zstart - dz)));
pv.addPhysVolID("barrel", 2).addPhysVolID("layer", l_id).addPhysVolID("module", mod_num);
DetElement r_module(sdet, m_base + "_neg", det_id);
r_module.setPlacement(pv);
for (size_t ic = 0; ic < sensVols.size(); ++ic) {
PlacedVolume sens_pv = sensVols[ic];
DetElement comp_elt(r_module, sens_pv.volume().name(), mod_num);
comp_elt.setPlacement(sens_pv);
}
}
dz = -dz;
phi += iphi;
++mod_num;
}
}
}
pv = motherVol.placeVolume(assembly);
pv.addPhysVolID("system", det_id);
sdet.setPlacement(pv);
return sdet;
}
// clang-format off
DECLARE_DETELEMENT(TrapEndcapTracker, create_detector)
DECLARE_DETELEMENT(MyGEMTrackerEndcap, create_detector)
```
![gem tracker](../gem_tracker_part2.png)
## Hands on challenges
### Update gem tracker
Swap out the gem tracker from part 1 with the detailed construction.
### Add top and bottom support for the GEM foil frame.
There is a side currently there
### Make the modules overlap
Currently the modules do not overlap much. Can you come up with a way to modify to get a nice overlap?
### What bug exists with the negative endcap?
If you uncomment the negative endcap, can you find out what is wrong with the construction?
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