CALIBRATION OF CURRENT INTEGRATORS USED WITH IONIZATION CHAMBERS. V. Spasić Jokić , I. Župunski , B. Vujičić , Z. Mitrović , V. Vujičić , Lj.Župunski Faculty of Technical Sciences, University of Novi Sad. Specific aims.
CALIBRATION OF CURRENT INTEGRATORS USED WITH IONIZATION CHAMBERS
V. SpasićJokić, I. Župunski, B. Vujičić, Z. Mitrović, V. Vujičić, Lj.Župunski
Faculty of Technical Sciences, University of Novi Sad
low as 1fA may be detected
using this function
IC self capacitance = 100 pF
Low current source
For current measurement
For charge measurement
Good reason for separate calibrations is that, one integrator is used with a number of chambers, so it would be inconvenient to calibrate it with every chamber.
corrected instrument reading at Q
Calibration method for a current-measuring feedback-controlled integrator
The output impedance of the current source must be large compared to R.
Verification of dosimeters used in health care and radiation protection is a legal requirement in Serbia
EUROMET Project n. 830, “Comparison of small current sources”
Laboratory for metrology at the Faculty of Technical Sciences, University of Novi Sad is accredited in terms of SRPS/ISO 17025 for verification of current integrators
Calibration uncertainty for current integrator can be expressed as
distribution was assumed
Preliminary uncertainty assessment for the current
generated by the source
Only type B evaluation has been considered
p(x)=C for I- Δ x I+Δ
p(x)= 0 in all other cases
The expanded uncertainty U with the coverage factor k = 2, corresponding
to the 95% confidence level, is often used to represent the
overall uncertainty, which relates to the accuracy of the measurement of
the quantity Q.