Fig. 2: CR39 measurements and results.
From: A multi-MeV alpha particle source via proton-boron fusion driven by a 10-GW tabletop laser
a Example of the unfiltered CR39 region at 0° in the case of CH-BN target after 3 h of etching, showing tracks from various particles emitted from plasma. The total number of accumulated shots is 670. b Example of the irradiated CR39 detector located at 39° and filtered by a 2.4-μm thick Al foil in the case of CH-BN target after 3 h of etching. All the dots are ascribable to alpha particles of different energies (larger dots correspond to low-energy alpha particle loosing most of their energy in the Al filter). c Example of the CR39 detector irradiated and etched under similar conditions as in a) in the case of reference PMMA (polymethyl methacrylate) target (no boron content). The total number of shots on the target was 104. The two tracks visible in the image are within the background level. d Histogram showing the area distribution of the detected particle tracks for all the CR39 samples under conditions described in a). The background influence is highlighted in red and is considered as 10 particles per statistics. e Angular distribution comparison of particles detected by CR39 in the unfiltered (blue solid line) and filtered (red dashed line) regions. The error bars are given by the standard deviation error. The background (80 particles/sr/shot) is already subtracted from the data.
