  A new method for determining plasma parameters from beam current transients
resulting from short pulse 1+ injection into a Charge Breeder Electron
Cyclotron Resonance Ion Source (CB-ECRIS) has been developed. The proposed
method relies on few assumptions, and yields the ionisation times
$1/n_e\left\langle\sigma v\right\rangle^{\text{inz}}_{q\to q+1}$, charge
exchange times $1/n_0\left\langle\sigma v\right\rangle^{\text{cx}}_{q\to q-1}$,
the ion confinement times $\tau^q$, as well as the plasma energy contents
$n_e\left\langle E_e\right\rangle$ and the plasma triple products $n_e
\left\langle E_e\right\rangle \tau^q$. The method is based on fitting the
current balance equation on the extracted beam currents of high charge state
ions, and using the fitting coefficients to determine the postdictions for the
plasma parameters via an optimisation routine.
  The method has been applied for the charge breeding of injected K$^+$ ions in
helium plasma. It is shown that the confinement times of K$^{q+}$ charge states
range from 2.6$^{+0.8}_{-0.4}$ ms to 16.4$^{+18.3}_{-6.8}$ ms increasing with
the charge state. The ionisation and charge exchange times for the high charge
state ions are 2.6$^{+0.5}_{-0.5}$ ms--12.6$^{+2.6}_{-3.2}$ ms and
3.7$^{+5.0}_{-1.6}$ ms--357.7$^{+406.7}_{-242.4}$ ms, respectively. The plasma
energy content is found to be $2.5^{+4.3}_{-1.8}\times 10^{15}$ eV/cm$^3$.
