Characterize the grid inefficiency correction of Frisch grid ionization chamber with Garfield and SRIM

Abstract

Grid inefficiency (GI) correction is critically important to accurately determine the energy and emission angle of charged particles in Frisch grid ionization chambers (FGIC). Presently, three correction methods have been proposed in the literature. All these three methods rely strongly on the accurate and stable calibration between two different electrical chain gains in experiments. To avoid these challenges, they are firstly investigated with Monte Carlo method by using Garfield and SRIM toolkit. Two types of grid wire (diameter 90 and 180 μm) were simulated to investigate the impacts of GI correction on energy correction, and ten different emission angles were adopted to estimate the effects of these correction methods on the angle reconstruction. The simulation results clearly distinguished the differences among these correction methods in energy determination. The correlation analysis (R = 0.99) among these different correction methods indicated that the impact of either correction approach is small on the determination of emission angle. The present work firstly investigates the effects of GI correction on emission angle with Monte Carlo methods, which is the basis of future work to measure the total kinetic energy and mass distribution of Fission Fragment (FF).

Detection of correlated fission fragments with a twin Frisch-grid ionization chamber

“…The pulse height of the grid signal was obtained by fitting the difference between the tail and baseline of the waveform without considering the bipolar structure at the center of the waveform. As discussed in our previous work [37], the grid inefficiency (GI) must be considered to accurately determine the emission angle and energy of fission fragments, and the Shockley-Ramo [33] method was adopted to correct GI. After GI correction, the emission angles were calculated by using a dual-parameter of anode and grid signals, which could be expressed as:…”

“…More detail of this process could be found in ref. [37,38]. Figure 6(a) shows the quality of the calculation by plotting the top side angle vs the bottom side angle.…”