PANDASimSD: A GEANT4 simulation of plastic scintillator antineutrino detector array

Requirements

• GEANT4: 11.2.1
• CRY: 1.7

Run the Simulation

1. Execute the biniary file directly after compilement to run in interactive mode. init_vis.mac will be loaded automatically in this situation.

2. Execute the biniary file with input *.mac files to run in batch mode. Three *.mac files at most, refer to detector and physics in Customized macro commands.

Spectra

spectra directory is for energy spectra storing. Refer to /source/spectra in Customized macro commands.

The spectrum format is showing below:

   Energy (MeV) | Relative intensity

e.g. 0.0253 eV monoenergetic particle

   2.53E-08  1

Data Saving

output directory is for data storing.

6 numbers in file names denote 6 optical-related parameters: absorptionLength, sigmaAlpha, rReflectivity, scintResol, PMTReflectivity and birksConstant. Refer to detector in Customized macro commands.

I. Detector module numbering:

e.g. 4 × 4 array

II. Binary (.data) files format (double of 8 bytes):

0 1 2 ... 14 15 0 1 2 ... 14 15 0 ...

• Files whos names contain Right or Left are the photo-electron data. The *Right*.data is exactly the same with the *Left*.data, in which both right and left PMT data are stored.

  0R 0L 1R 1L ... 14R 14L 15R 15L 0R 0L ...

• The data shown below are not stored in form of the detector array.

  betaKEHe8, betaKELi9, decayTimeHe8, decayTimeLi9, neutronGT, neutronKE, capTimeH, capTimeGd, muonKEPrimary, neutronKEPrimary

III. Unit

• Time: μs
• Energy deposition: MeV
• Kenitic energy: keV
• Primary kenitic energy: GeV
• Track length: mm

Customized macro commands

I. detector

Use this command before /run/initialize.
Use this command in the second or third input *.mac file, the first should be the one with /run/initialize and /run/beamOn.
This *.mac file is optional. Without this file default detector setup wil be used.

/detector/arraySize
/detector/detectorX
/detector/detectorY
/detector/detectorZ
/detector/moduleDistance
/detector/gdFilmThickness
/detector/addLabRoom
/detector/sigmaAlpha
/detector/rReflectivity
/detector/scintResol
/detector/PMTReflectivity
/detector/birksConstant
/detector/absorptionLength

1. /detector/arraySize

   • Detector array size, a positive integer.
   • Default value: 4.

2. /detector/detectorX

   • Detector X dimension, a positive double with unit (cm by default).
   • Default value: 10. cm.

3. /detector/detectorY

   • Detector Y dimension, a positive double with unit (cm by default).
   • Default value: 10. cm.

4. /detector/detectorZ

   • Detector Z dimension, a positive double with unit (cm by default).
   • Default value: 100. cm.

5. /detector/moduleDistance

   • Distance between modules, a positive double with unit (cm by default).
   • Default value: 2. cm.

6. /detector/gdFilmThickness

   • Gd film thickness, a positive double with unit (um, μm, by default).
   • Default value: 30. um.

7. /detector/addLabRoom

   • Available values: true/false.
   • Adding/removing lab room.
   • Default value: true.

8. /detector/sigmaAlpha

   • sigma_alpha of scintillator-reflector/PMT boundary, a non-negative double.
   • Default value: 0.

9. /detector/rReflectivity

   • Reflection probability of scintillator-reflector boundary, range: [0, 1].
   • Default value: 1.

10. /detector/scintResol

    • Scintillation yield resolution scale of the scintillator, a non-negative double.
    • Default value: 0.

11. /detector/PMTReflectivity

    • Reflection probability of scintillator-PMT boundary, range: [0, 1].
    • Default value: 1.

12. /detector/birksConstant

    • Birk's constant, a non-negative double in mm/MeV.
    • Default value: 0.

13. /detector/absorptionLength

    • Absorption length of plastic scintillator, a positive double with unit (cm by default).
    • Default value: 380.

II. source

Use this command after /run/initialize

/source/type              
/source/spectra     
/source/position          
/source/neutrinoPosition

1. /source/type

   • Available values: Cs137/Co60/Na22/Cs137g/Co60g/Am-Be-n/GUN/He8/Li9/NEUTRINO/MUON/COSMICNEUTRON/CRY (Linux only)/GPS.
   • Cs137/Co60/Na22/Cs137g/Co60g/Am-Be-n/GUN with position CENTER/EDGE;
     GUN with position INSIDE or COMMAND (means defined by UI command /gun/position). Energy, momentum, particle etc. must be defined with source GUN using UI command /gun/**.
     Position, momentum, particle etc. must be defined with source GPS using UI command /gps/**.
   • Default value: NEUTRINO.

2. /source/spectra

   • Spectra of neutron and positron, two strings at most. See spectra directory.
     First one should be spectrum of neutron.
     Second one, if there is, should be spectrum of positron.
   • Command is valid only for NEUTRINO, Am-Be-n and COSMICNEUTRON.
   • Default value: IBDNeutron.spec IBDPositron.spec.

3. /source/position

   • Available values: CENTER/EDGE/INSIDE/COMMAND
   • Position for Cs137/Co60/Na22/Cs137g/Co60g/Am-Be-n/GUN
     Direction must be defined for GUN with position CENTER/EDGE.
     Direction and position must be defined for GUN with position COMMAND.
     Direction is isotropic for GUN with position INSIDE.
   • Default value: CENTER.

4. /source/neutrinoPosition

   • Position for NEUTRINO, two positive integers [0 - size × size, 0 - 5].
     First integer is position in the detector array, size × size means random.
     Second integer is position in the detector module, 5 means random.
     Second integer is valid only when arrayPosition < size × size.
   • Default value: size × size 5.

III. physics

Use this command in the second or third input *.mac file, the first should be the one with /run/initialize and /run/beamOn.
This *.mac file is optional. Without this file optical process and muonic atom decay process will be off.

/physics/optical
/physics/muonicDecay

1. /physics/optical

   • Available values: true/false.
   • Turning on/off optical process.
   • Default value: true.

2. /physics/muonicDecay

   • Available values: true/false.
   • Turning on/off muonic atom decay process.
   • Default value: true.

IV. time

Use this command after /run/initialize

/time/timeInterval

1. /time/timeInterval
   • Time interval between parent particle and secondaries, a positive double with unit (us, μs, by default).
   • If time interval between parent particle and secondaries is bigger than this value, they will be treated as two signals.
   • Default value: 1. us.