Abstract
The influence of preionization around the insulator sleeve by a mesh-type
β
source
(
Ni
63
28
)
for the x-ray emission from a (2.3-3.9 kJ) plasma focus device is investigated. Quantrad Si
p
-
i
-
n
diodes along with suitable filters are employed as time-resolved x-ray detectors and a multipinhole camera with absorption filters is used for time-integrated analysis. X-ray emission in
4
π
geometry is measured as a function of argon and hydrogen gas filling pressures with and without
β
source at different charging voltages. It is found that the pressure range for the x-ray emission is broadened, x-ray emission is enhanced, and shot to shot reproducibility is improved with the
β
source. With argon, the
Cu
K
α
emission is estimated to be 27.14 J with an efficiency of 0.7% for
β
source and 21.5 J with an efficiency of 0.55% without
β
source. The maximum x-ray yield in
4
π
geometry is found to be about 68.90 J with an efficiency of 1.8% for
β
source and 54.58 J with an efficiency of 1.4% without
β
source. With hydrogen,
Cu
K
α
emission is 11.82 J with an efficiency of 0.32% for
β
source and 10.07 J with an efficiency of 0.27% without
β
source. The maximum x-ray yield in
4
π
geometry is found to be 30.20 J with an efficiency of 0.77% for
β
source and 25.58 J with an efficiency of 0.6% without
β
source. The x-ray emission with Pb insert at the anode tip without
β
source is also investigated and found to be reproducible and significantly high. The maximum x-ray yield is estimated to be 46.6 J in
4
π
geometry with an efficiency of 1.4% at 23 kV charging voltage. However, degradation of x-ray yield is observed when charging voltage exceeds 23 kV for Pb insert. From pinhole images it is observed that the x-ray emission due to the bombardment of electrons at the anode tip is dominant in both with and without
β
source.