Initial Charge Cloud Diameter Estimation

1

Hello all I am looking into determining the initial charge cloud diameter. I plotted the propagation of electrons and holes but I wanted to know if I can extract the location of the charges that are propagated. Thank you!

[AllPix]
log_level = "WARNING"
log_format = "LONG"
number_of_events = 1
detectors_file = "detector.conf"
model_paths = ./
multithreading = true
random_seed = 1234

[GeometryBuilderGeant4]
world_material = "air"

[DepositionGeant4]
physics_list = FTFP_BERT_LIV
particle_type = "gamma"
source_energy = 122keV
source_position = 0 0 -20mm
source_type = "beam"
beam_direction = 0 0 1
number_of_particles = 1

[ElectricFieldReader]
model="linear"
bias_voltage=-500V
depletion_voltage=-100V

[GenericPropagation]
mobility_model = "constant"
mobility_electron = 1090cm*cm/V/s
mobility_hole = 110cm*cm/V/s
temperature = 293K
charge_per_step = 1
integration_time = 750ns
max_charge_groups = 0
propagate_holes = true
output_plots = 1
output_linegraphs = true
output_linegraphs_collected = true
output_plots_align_pixels = true


[SimpleTransfer]
max_depth_distance = 5um
output_plots = true

[DefaultDigitizer]
threshold = 600e
output_plots = true
2

Hi @oobie2142

this information is available from the DepositedCharge object’s getLocalPosition().

If you want to know for a given PixelHit, where the charges came from, you traverse the Monte Carlo history backwards

PixelHit::getPixelCharge()::getPropagatedCharges()::getDepositedCharge()

Cheers,
Simon

3

@simonspa Thank you! If I include the DepositedCharge in the RootObjectWriter Module can I plot the distribution of local x and y coordinates and that would be the same thing?

Sorry I have yet to try and use allpix outside the scripting method.

4

Hi @oobie2142

it really depends what you want to look at, the information is all there. If you just want the initial charge distribution, plotting DepositedCharge positions is what you want.

/Simon

5

Thanks! For the units does it change depending on the ROOT Object?

Or is local and global positions always in mm?

6

Always base units: