Introduction
Persint 1 is an interactive visualization program developed for ATLAS. The program has been operational for many years and was used for:
- Designing the muon spectrometer
- Debugging the successive detector layouts, in particular resolving volume clashes
in the GeoModel
- Optimizing the reconstruction software
- Analysing cosmic ray data in the commissioning phase
- Analysing collision events (data and Monte Carlo)
The new version described in this manual retains all the functionalities of the original package and features a modern graphic user interface (GUI) and an easy to use ?le management system. The new interface, which uses the Qt library from Trolltech, makes it easy to interact with objects or applications.
Persint has many remarkable features, which can be used to visualize events in their most intricate detail. It is currently running on Linux , Mac OS and Windows operating systems and is interfaced with ATHENA, the general framework for data analysis in ATLAS. The package is being used with simulated events and with real data:
cosmic
ray events and events from collisions.
Persint is particularly well suited for understanding complicated events, when the visual representation of the detector's response becomes crucial.
1 Main features of Persint
The Persint program is designed for the three-dimensional representation of objects. It visualizes detector geometries using an interface with AMDB2, an ASCII ?le containing the primary numbers used to build the muon spectrometer geometry. It also accesses AGDD3, an XML-based geometry description language for the Atlas generic detector, mainly concerned with the inert material in the spectrometer. Persint interfaces with a variety of independent applications, in a fully interactive way. These applications include visualization of active detectors, inactive material, and the magnetic ?eld map, as well as the detection of volume clashes, the display of event hits from ?les of physics events
(simulated or data). It is possible to display events reconstructed with any reconstruction program active in ATHENA. Furthermore it is also possible to interactively run the
embedded muon reconstruction program MuonBoy, and display the results.
For spatial navigation, one can set the desired perspective for the 3D-view and display
2D-projections along various axes (Fig. 1). It is possible to change the viewpoint in order
to best visualize the desired region, to displace the viewed objects with operations like
translation, rotation and zoom.
The remarkable features o?ered by Persint are:
- 3-dimentional representation of objects in full volumes or wire mode" using the
computation of hidden faces
- Spatial navigation with real time displacements
- Focal length adjustment, from isometry to wide angle
1Persint: PERSpectively INTeractive
2Atlas Muon Data Base
3Atlas Generic Detector Description
13 1 MAIN FEATURES OF PERSINT
- Interfaces with numerous applications
- Display of magnetic ?eld map; tracking in magnetic ?eld of generated muons
- Displays can be exported as .png, .jpg, .bmp, or .svg ?les.
- Highlight of volume edges; adjustable light intensity on volume faces
- Detection of clashing volumes and highlight of intersections
- Boolean volume operations (addition, subtraction, intersection).
CONTENTS (TABLE DES MATIERES)
4 CONTENTS
Contents
1 Main features of Persint 12
2 Architecture 14
3 Installation on supported platforms 14
4 Starting Persint 15
5 The Graphic User Interface 17
5.1 Items of the Graphic User Interface . . . . . . . . . . . . . . . . . . . . . . 17
5.2 Online help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3 Speeding up Persint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.4 Toolbars or Menus ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6 Exercise 1: Setting the stage 19
6.1 Necessary ?les . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1.1 Detector description and magnetic ?eld . . . . . . . . . . . . . . . 19
6.1.2 Example" ?les for Event 4023 . . . . . . . . . . . . . . . . . . . . 21
6.2 Interfaces to applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.3 Displaying detector layouts and events . . . . . . . . . . . . . . . . . . . . 22
6.4 Save, Export, and Print views . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.5 Dressing the display with captions, logos, and pictures . . . . . . . . . . . 26
7 Exercise 2: Muon tracks in your own layout 29
7.1 Generate muon tracks at the IP . . . . . . . . . . . . . . . . . . . . . . . . 29
7.2 Display the detector using the AMDB interface . . . . . . . . . . . . . . . 30
7.2.1 Draw MDT muon chambers . . . . . . . . . . . . . . . . . . . . . . . 30
7.2.2 Draw RPC muon chambers . . . . . . . . . . . . . . . . . . . . . . . 30
7.2.3 Draw Inner Detector . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.2.4 Optimizing the view: a ?rst try at navigation . . . . . . . . . . . . 31
7.2.5 Starting anew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.3 Place the calorimeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.4 Save ?les for future use . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.5 Place inert material using the AGDD interface . . . . . . . . . . . . . . . 33
7.6 The Dead material function . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.6.1 Preparing the working view . . . . . . . . . . . . . . . . . . . . . . 34
7.6.2 Use of the Dead material function . . . . . . . . . . . . . . . . . . 34
7.7 Look at the event in detail . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.7.1 Show ATLAS coordinate system . . . . . . . . . . . . . . . . . . . 35
7.7.2 View the event in the X-projection . . . . . . . . . . . . . . . . . . 35
7.7.3 Zoom-in on muon chambers . . . . . . . . . . . . . . . . . . . . . . 36
8 Exercise 3: Practicing Navigation 37
8.1 Preparing the working view . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.2 The Default mode: a magic wand . . . . . . . . . . . . . . . . . . . . . . . 38
8.3 Single functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8.4 More functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9 Exercise 4: Exploring more features 41
9.1 Volume information labels . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.1.1 Volume identi?cation with information boxes . . . . . . . . . . . . 41
9.1.2 Label maker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.2 Hide/Displace volumes or super-volumes . . . . . . . . . . . . . . . . . . . 43
9.2.1 Hide volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.2.2 Hiding volumes, the fast way . . . . . . . . . . . . . . . . . . . . . 44
9.2.3 Displacements of volumes . . . . . . . . . . . . . . . . . . . . . . . 44
9.3 Compare geometries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.4 Detect volume clashes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
9.5 Animation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
9.6 Wire mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.7 Magnetic Field Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.7.1 Loading a Magnetic Field ?le . . . . . . . . . . . . . . . . . . . . . 49
9.7.2 Display B-?eld lines . . . . . . . . . . . . . . . . . . . . . . . . . . 50
9.7.3 Display B-?eld maps . . . . . . . . . . . . . . . . . . . . . . . . . . 51
9.8 X0 map: Distribution of material . . . . . . . . . . . . . . . . . . . . . . . 54
9.9 Map of the expected number of crossed muon stations . . . . . . . . . . . 55
10 Exercise 5: ATLAS Physics Events (1) 56
10.1 Input ?les . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
10.1.1 Files loaded by the user . . . . . . . . . . . . . . . . . . . . . . . . 56
10.1.2 Event dependent ?les . . . . . . . . . . . . . . . . . . . . . . . . . 56
10.2 Display physics events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
10.3 Select Sectors to be displayed . . . . . . . . . . . . . . . . . . . . . . . . . 58
10.4 Dressing the event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
10.5 Save the view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
10.6 Changing the event ?le . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
10.7 Scanning events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
10.7.1 Manual scanning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.7.2 Automatic scanning . . . . . . . . . . . . . . . . . . . . . . . . . . 62
10.7.3 Visualization properties . . . . . . . . . . . . . . . . . . . . . . . . 62
10.7.4 Using 2D projections . . . . . . . . . . . . . . . . . . . . . . . . . . 64
11 Exercise 6: ATLAS Physics events (2) 65
11.1 Muon spectrometer data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
11.1.1 Map (?; ') of expected number of stations . . . . . . . . . . . . . . 65
11.1.2 ATHENA reconstructed segments and tracks . . . . . . . . . . . . 66
11.1.3 Simulated muon tracks . . . . . . . . . . . . . . . . . . . . . . . . . 70
11.1.4 Interactive reconstruction with Muonboy . . . . . . . . . . . . . . 70
11.1.5 Color code for MDT hits . . . . . . . . . . . . . . . . . . . . . . . 73
11.2 Vertex display and Inner Detector data . . . . . . . . . . . . . . . . . . . 75
11.2.1 Vertex display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
11.2.2 Histogram of d0 (primary vertex) . . . . . . . . . . . . . . . . . . . 76
11.3 Calorimeter data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
11.3.1 Display calorimeter hits . . . . . . . . . . . . . . . . . . . . . . . . 77
11.3.2 Display calorimeter hits with increased thresholds . . . . . . . . . 78
11.3.3 Histogram of calorimeter hits . . . . . . . . . . . . . . . . . . . . . 81
12 Persint: a versatile tool 83
12.1 An analysis tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
12.2 Study of the geometry and dead material . . . . . . . . . . . . . . . . . . 85
6 CONTENTS
13 Selected event displays 86
14 Useful hints 96
