1. V. Chepel, V. Domingos, R. Martins, A. Morozov, F. Neves and
LIP-Coimbra 2014
ANTS 2: Simulation and data processing package for Anger camera-type detectors
V. Chepel, V. Domingos, R. Martins, A. Morozov, F. Neves and
V. Solovov

2. Anger camera-type detectors
Optical
photons
Electrical
signals
Array of
optical sensors
Event position (or track) reconstruction
Detection
medium
Particle
Interaction of particle with detection medium
Localized emission of light (primary or secondary scintillation)

3. Motivation LIP: three types of Anger camera-type detectors
Medical gamma cameras (our current project)
GSPC neutron detectors (FP7-NMI3 collaboration)
LXe dark matter detectors (ZEPLIN, LUX, LZ)
Simulations are required for:
Detector design and optimization
Development of new reconstruction algorithms
Processing of experimental data

4. Package highlights Simple tools to define detector geometry (3D)
Solid, liquid and gaseous scintillators
Primary and secondary scintillation
Detailed model of optical sensors
Statistical reconstruction of event position (3D); track reconstruction
Large set of tools to analyze data and to test reconstruction quality

5. Package highlights Open source (C++)
Multiplatform (Windows, Linux; Mac soon)
Graphical interface (fully interactive) + batch mode
Extensive use of CERN ROOT (3D navigation, visualization, math libraries)
FANN library for artificial neural networks

6. Fully custom detector geometry
CERN ROOT TGeoManager class
is used for 3D navigation and visualization

7. Simulation modes Direct mode: Simulation of an experiment:
An event is simulated by generating light emission from one or several point sources
Simulation of an experiment:
User defines a radiation source (or several ones), and provides its characteristics.
Energy deposition due to interaction of primary and secondary particles with detector media lead to light emission.

8. Event reconstruction algorithms
Center of Gravity
Statistical reconstruction
3D position reconstruction with one plane of sensors!
Possibility to reconstruct double events!
Adaptive algorithms (work in progress)
Artificial neural networks (work in progress)

9. Compact gamma camera
Optical photon tracks are shown with teal lines

10. Neutron detectors
Neutron “tracks” (red) ending with emission of p and t

11. Dark matter detectors
LZ detector design optimization: 217 or 271 PMTs?

12. Track reconstruction Blue track: simulated (alpha particle)
Red track: reconstructed using time-
resolved secondary scintillation
PMT2
PMT1
PMT signals vs time
Ionization cloud drifts to the region where secondary scintillation is generated
Photons have emission time stamp!
Signal
PMT1
PMT2
Time
Time

13. Gamma camera + pinhole collimator
LYSO crystal
Pinhole
Phantom
Lead block
with two conical holes
Co-57 gamma source is positioned behind the phantom (mask)
Red dots are reconstructed positions of interaction of gammas with LYSO scintillator

14. Experimental data processing
Processing of first dataset obtained at the detector prototype.
Center of
Gravity
Statistical:
Least Squares
Sum signal spectrum
Simulated LRFs

15. Current work and future plans
Parameterization of response of optical sensors in 3D
3D reconstruction of events with low number of photons (~5000)
Application of adaptive reconstruction algorithms for medical gamma cameras
Real-time event reconstruction