Development of fIREBall

Kevin Lee
Graduate Student
University of Notre Dame

Measurement of conversion electrons in coincidence with gamma rays is an important aspect of nuclear structure studies. We are building on the current existing Internal Conversion Electron Ball (ICEBall) mini-orange array of Si(Li) detectors to construct an improved fInternal ConveRsion Electron Ball (fIREBall) array with improved efficiency and performance. The current array of six mini-orange Si(Li) detectors will be replaced with six new, thicker Si(Li) detectors and the magnet filters will be replaced with new, optimized designs. The magnetic elements are used to create a field that the electrons follow after being produced in nuclear reactions. Using a combination of FreeCAD, COMSOL, and Geant4, we created an efficient, working simulation to identify magnet shapes that would improve the absolute efficiency of ICEBall. We have also commissioned a new pair of Bismuth Germanate (BGO) Compton Suppression shields to use with either the GEORGINA or Clover HPGe detectors. Preliminary experimental tests of the new magnet shapes and the BGO shields have been completed. Once fIREBall is fully assembled, we will proceed onto repeating a previous experiment on ICEBall, a ^152,154Sm(α,2n)^154,156Gd reaction, to confirm/determine the improvements achieved, specifically in coincidence measurements. Details about the development work, the preliminary results, and the challenges encountered will be discussed.

Hosted by Prof. Aprahamian

Presented both in person and via zoom. Please email nsladmin@nd.edu for zoom link.