Radiation Safety

Provides functions for radiation safety, also known as "radiation protection" and "radiological control". The science of radiation protection is called "health physics" and its engineering functions are called "radiological engineering". Functions in this package cover many of the computations needed by radiation safety professionals. Examples include: obtaining updated calibration and source check values for radiation monitors to account for radioactive decay in a reference source, simulating instrument readings to better understand measurement uncertainty, correcting instrument readings for geometry and ambient atmospheric conditions. Many of these functions are described in Johnson and Kirby (2011, ISBN-13: 978-1609134198). Utilities are also included for developing inputs and processing outputs with radiation transport codes, such as MCNP, a general-purpose Monte Carlo N-Particle code that can be used for neutron, photon, electron, or coupled neutron/photon/electron transport (Werner et. al. (2018) ).

radsafer

Overview

The radsafer package was developed to provide:

• general functions helpful in the practice of radiation safety, for example, decay-corrections

• easy access to radionuclide data from the RadData package

• functions for instrumentation and radiation transport modeling

Families of functions

Related functions are identified as members of these families:

• decay corrections

• radionuclides

• radiation measurements

• mcnp tools

• and a few stand alone functions

Decay Correction Functions

Radsafer includes several functions to manage radioactive decay corrections:

dk_correct provides decay-correction of single radionuclides. (Radioactive in-growth is not accounted for.)

Usage Examples

Use the radionuclide library to find the half-life

dk_correct(RN_select = "Sr-90",
           date1 = "2015-01-01", #Original activity date
           date2 = c("2025-01-01","2035-01-01"), #Decay to these dates
           A1 = 10000) #Original activity (arbitrary units)
#>     RN half_life units decay_mode
#>  Sr-90     28.79     y         B-
#> 
#>     RN RefValue    RefDate   TargDate dk_value
#>  Sr-90    10000 2015-01-01 2025-01-01 7860.079
#>  Sr-90    10000 2015-01-01 2035-01-01 6178.491

Enter your own half-life

dk_correct(half_life = 10, #10 something - need unit
           time_unit = "y",#unit is years
           date1 = "2010-01-01") #original date is identified 
#>  half_life RefValue    RefDate   TargDate  dk_value
#>         10        1 2010-01-01 2026-07-14 0.3179556
# Since date2 is not identified, it defaults to the computer's system date "today".

Reverse usage is no problem - find out activity at a past date

dk_correct(RN_select = "Cs-137", 
           date1 = "2026-01-01", #known activity on this date
           date2 = c("2016-01-01","2006-01-01"), #find activity on these earlier dates
           A1 = 3000) #original activity (arbitrary units)
#>      RN half_life units decay_mode
#>  Cs-137   30.1671     y         B-
#> 
#>      RN RefValue    RefDate   TargDate dk_value
#>  Cs-137     3000 2026-01-01 2016-01-01 3775.032
#>  Cs-137     3000 2026-01-01 2006-01-01 4749.991

Other decay functions:

• How long does it take to decay something with a given activity, or how old is a sample if it has decayed from?

dk_time(half_life = 5730, A0 = 14, A1 = 1)
#> [1] 21816.14
  
RN_find_parent("Po-210")
#>       RN
#> 1 At-210
#> 2 Bi-210

Extract radionuclide data from RadData

Plot an emission spectrum

RN_plot_spectrum(
  desired_RN = c("Pu-238", "Pu-239", "Am-241"), rad_type = "A",
  photon = FALSE, prob_cut = 0.01, log_plot = 0)

RN_plot_spectrum(
     desired_RN = c("Sr-90", "Y-90"), rad_type = "B-")

RN_plot_spectrum(desired_RN = c("Co-60", "Ba-137m"), rad_type = "G")

Search by alpha, beta, photon or use the general screen option.

# tight energy limits around 1 MeV
search_results <- RN_search_phot_by_E(E_min = 0.99, 
                    E_max = 1.01, 
# half-life between 13 and 15 minutes (convert from seconds)
                    min_half_life_seconds = 13 * 60, 
                    max_half_life_seconds = 15 * 60, 
# only branches with probabilities >= 10%
                    min_prob = 0.1)

RN_plot_spectrum(desired_RN = search_results$RN, rad_type = "G", prob_cut = 0.1)
#> [1] "No matches"

radiation monitoring

disk_to_disk_solid_angle(r.source = 45/2, gap = 20, r.detector = 12.5, runs = 1e4, plot.opt = "2d")

#>    mean_eff         SEM
#>  0.05132699 0.002208406

scaler_sim(true_bkg = 50, true_samp = 10, ct_time = 20, trials = 1e5)

rate_meter_sim(cpm_equilibrium = 270, meter_scale_increments = seq(100, 1000, 20))

functions to help with radiation transport modeling

mcnp_sdef_erg_line("Co-60", photon = TRUE, cut = 0.01, erg.dist = 13)
#> # A tibble: 6 × 6
#>   RN    code_AN E_MeV     prob code_num is_photon
#>   <chr> <chr>   <dbl>    <dbl>    <dbl> <lgl>    
#> 1 Co-60 G       0.347 0.000075        1 TRUE     
#> 2 Co-60 G       0.826 0.000076        1 TRUE     
#> 3 Co-60 G       1.17  0.998           1 TRUE     
#> 4 Co-60 G       1.33  1.000           1 TRUE     
#> 5 Co-60 G       2.16  0.000012        1 TRUE     
#> # ℹ 1 more row

mcnp_matrix_rotations("z", 30)
#> [1]  0.8660254  0.5000000  0.0000000 -0.5000000  0.8660254  0.0000000
#> [7]  0.0000000  0.0000000  1.0000000

Getting help

If you encounter a clear bug, please file an issue with a minimal reproducible example on GitHub.