run_MC_TL_TUN {RLumCarlo}

Run Monte-Carlo Simulation for TL (tunnelling transitions)

Description

Runs a Monte-Carlo (MC) simulation of thermoluminescence (TL) caused by tunnelling (TUN) transitions. Tunnelling refers to quantum mechanical tunnelling processes from the excited state of the trap into a recombination centre. The heating rate in this function is assumed to be 1 K/s.

Usage

run_MC_TL_TUN(
  s,
  E,
  rho,
  r_c = 0,
  times,
  b = 1,
  clusters = 10,
  N_e = 200,
  delta.r = 0.1,
  method = "par",
  output = "signal",
  ...
)

Arguments

s

list (required): The effective frequency factor for the tunnelling process (s^-1)

E

numeric (required): Thermal activation energy of the trap (eV)

rho

numeric (required): The dimensionless density of recombination centres (defined as \rho' in Huntley 2006)

r_c

numeric (with default): Critical distance (>0) that is to be used if the sample has been thermally and/or optically pretreated. This parameter expresses the fact that electron-hole pairs within a critical radius r_c have already recombined.

times

numeric (required): The sequence of temperature steps within the simulation (s). The default heating rate is set to 1 K/s. The final temperature is max(times) * b

b

numeric (with default): the heating rate in K/s

clusters

numeric (with default): The number of created clusters for the MC runs. The input can be the output of create_ClusterSystem. In that case n_filled indicate absolute numbers of a system.

N_e

numeric (with default): The total number of electron traps available (dimensionless). Can be a vector of length(clusters), shorter values are recycled.

delta.r

numeric (with default): The increments of the dimensionless distance r'

method

character (with default): Sequential 'seq' or parallel 'par'processing. In the parallel mode the function tries to run the simulation on multiple CPU cores (if available) with a positive effect on the computation time.

output

character (with default): output is either the 'signal' (the default) or 'remaining_e' (the remaining charges/electrons in the trap)

...

further arguments, such as cores to control the number of used CPU cores or verbose to silence the terminal

Details

The model

I_{TUN}(r',t) = -dn/dt = (s * exp(-E/(k_{B} * T))) * exp(-(\rho')^{-1/3} * r') * n(r',t)

Where in the function:
s := frequency for the tunnelling process (s^-1)
E := thermal activation energy (eV)
k_{B} := Boltzmann constant (8.617 x 10^-5 eV K^-1)
T := temperature (°C)
r' := the dimensionless tunnelling radius
\rho' := ⁠rho'⁠, the dimensionless density of recombination centres (see Huntley (2006))
t := time (s)
n := the instantaneous number of electrons at distance r'

Value

This function returns an object of class RLumCarlo_Model_Output which is a list consisting of an array with dimension length(times) x length(r) x clusters and a numeric time vector.

Function version

0.1.0

How to cite

Friedrich, J., Kreutzer, S., 2022. run_MC_TL_TUN(): Run Monte-Carlo Simulation for TL (tunnelling transitions). Function version 0.1.0. In: Friedrich, J., Kreutzer, S., Pagonis, V., Schmidt, C., 2022. RLumCarlo: Monte-Carlo Methods for Simulating Luminescence Phenomena. R package version 0.1.9. https://CRAN.R-project.org/package=RLumCarlo

Author(s)

Johannes Friedrich, University of Bayreuth (Germany), Sebastian Kreutzer, Geography & Earth Sciences, Aberystwyth University (United Kingdom)

References

Huntley, D.J., 2006. An explanation of the power-law decay of luminescence. Journal of Physics: Condensed Matter, 18(4), 1359.

Pagonis, V. and Kulp, C., 2017. Monte Carlo simulations of tunneling phenomena and nearest neighbor hopping mechanism in feldspars. Journal of Luminescence 181, 114–120. doi:10.1016/j.jlumin.2016.09.014

Pagonis, V., Friedrich, J., Discher, M., Müller-Kirschbaum, A., Schlosser, V., Kreutzer, S., Chen, R. and Schmidt, C., 2019. Excited state luminescence signals from a random distribution of defects: A new Monte Carlo simulation approach for feldspar. Journal of Luminescence 207, 266–272. doi:10.1016/j.jlumin.2018.11.024

Further reading

Aitken, M.J., 1985. Thermoluminescence dating. Academic Press.

Jain, M., Guralnik, B., Andersen, M.T., 2012. Stimulated luminescence emission from localized recombination in randomly distributed defects. Journal of Physics: Condensed Matter 24, 385402.

Examples

## the short example
run_MC_TL_TUN(
 s = 1e12,
 E = 0.9,
 rho = 1,
 r_c = 0.1,
 times = 80:120,
 b = 1,
 clusters = 50,
 method = 'seq',
 delta.r = 1e-1) %>%
plot_RLumCarlo()

## Not run: 
## the long (meaningful example)
results <- run_MC_TL_TUN(
 s = 1e12,
 E = 0.9,
 rho = 0.01,
 r_c = 0.1,
 times = 80:220,
 clusters = 100,
 method = 'par',
 delta.r = 1e-1)

## plot
plot_RLumCarlo(results)

## End(Not run)