Manual Fine-Tuning Iterations

Introduction

These are the starting conditions of the Calibrate Manually tab following simulated annealing of the radionuclide source strength distribution in the Surface Measurements tab.

CGD282ManualPass0
CGD282ProfilePass0

Step 1

Begin by adjusting the Dose Calibration slider until the dose profile curve passes through the 5 mm measurement point.

CGD282ManualStep1
CGD282ProfileStep1

Step 2

By inspection, adjust the Crossover, Nearfield slope and other Nearfield sliders to make the dose profile curve a smooth fit to the nearfield points (range 0 to 2 mm).

CGD282ManualStep2
CGD282ProfileStep2

Step 3

By inspection, adjust the Farfield power and Farfield threshold sliders until the dose profile curve passes through the farfield points (range 7 to 10 mm).

CGD282ManualStep3
CGD282ProfileStep3

Iterations 2,3,4 etc...
  1. Next, adjust the Crossover field to minimize the RMS error in the range 0..5 mm.
  2. Next, adjust the Nearfield slope field to minimize the RMS error in the range 0..5 mm.
  3. Next, adjust the Anisotropy shift field to minimize the RMS error in the range 0..5 mm.
  4. Next, adjust the Anisotropy threshold field to minimize the RMS error in the range 0..5 mm.
  5. Next, adjust the Farfield power field to minimize the RMS error in the range 0..10 mm.
  6. Next, adjust the Farfield threshold field to minimize the RMS error in the range 0..10 mm.
  7. Next, adjust the Dose Calibration field to minimize the RMS error in the range 0..5 mm.

Repeat steps 2-8 above until the RMS error over the range 0..10 mm can no longer be reduced. The bumper buttons change the parameter value by increments of .001. Use the bumpers to fine tune the fit when the slider increments become ineffective.

Optionally, return to the surface measurements tab and re-solve using the current starting parameters (i.e. do NOT click the distribute uniformly button, just click the solve button, and then repeat the manual fine tuning process). A second annealing can occasionally improve the surface and axis curve fit by a fraction of a %.

CGD282FinalManual

RMS % error (0 to 10.0 mm) = 1.723

CGD282FinalDoseProfile