Optimization of the marinelli beaker dimensions using genetic algorithm

- A sensitivity analysis of the optimum dimensions of marinelli beaker to different parameters of HPGe detector was performed.
- A genetic algorithm (GA) was developed using matlab software to solve optimization process.
- Monte Carlo MCNPX computational code was used to simulate the HPGe detector and couple with the GA.
- Optimum values of the beaker for HPGe in different Ge sizes and different beaker volumes was calculated.
- Two functions were suggested to calculate r and h1 (parameters of the beaker) based on fitting method.

A computational code, based on the genetic algorithm and MCNPX version 2.6 code was developed and used to investigate the effects of some important parameters of HPGe detector (such as Al cap thickness, dead-layer thickness and Ge hole size) on optimum dimensions of marinelli beaker. In addition, the effects of detector material on optimal beaker dimensions were also investigated. Finally, the optimized beaker dimensions at various beaker volumes (300, 500, 700, 1000 and 1500 cm3) were determined for some conventional Ge detectors with different crystal sizes (16 sizes). These sets of data then were used to drive mathematical formulas (obtained by best fitting to data sets).The results showed that, there is no meaningful correlation between the optimum dimensions of the beaker and each of the dead-layer thickness, Al cap thickness and the Ge-crystal hole size. On the other hand, the optimum beaker radius increases with decreasing the density of the detector material while the beaker height decreases.