Primary standard measuring facilities for the realization of the unit of 
air kerma:
A: Free-air ionization chambers for X-radiations between 7.5 kV and 400 kV
| Designation | Type | Energy range | Expanded uncertainty (k = 2) |
| PK100 | Parallel-plate ionization chamber | 7.5 kV - 150 kV | 0.62 % |
| FK | Cylindrical ionization chamber | 30 kV -300 kV | 0.60 % |
| PK 400 | Parallel-plate ionization chamber | 50 kV - 400 kV | 0.65 % |
B: Cavity ionization chambers for 137Cs- and 60Co gamma radiation
| Designation | Type | Measurement volume | Expanded uncertainty (k = 2) | |
| 60Co | 137Cs | |||
| HRK-1 | Cylindrical chamber | 0.5539 cm3 | 0.46 % | 0.44 % |
| HRK-2 | Cylindrical chamber | 1.5190 cm3 | 0.42 % | 0.40 % |
| HRK-3 | Flat chamber | 6.138 cm3 | 0.45 % | 0.42 % |