Add default initializaiton of the member pointer
Add default initializaiton of the member pointer

alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,alexkernphysiker/j-pet-framework,JPETTomography/j-pet-framework,JPETTomography/j-pet-framework,JPETTomography/j-pet-framework,alexkernphysiker/j-pet-framework