PTW 30013 - Page 22

Farmer Chamber
Ionization Chamber
Type 30010, 30011, 30012, 30013
Technical Manual - Technical Specifications
22 D596.131.00/05 en
Device designation Farmer chambers
ionization chambers, types 30010, 30013
Dimensions refer to Figure 4 and Figure 5
Response 20 nC/Gy
Chamber voltage nominal +400 V
maximal ±500 V
Leakage current ≤ ±4 fA
Cable leakage ≤ 1 pC/(Gy∙cm)
Cable length T30010: 1 m
T30013: 1.3 m
min. bending radius 20 mm (static)
min. bending radius 50 mm (for up to a maximum of 50 repetitions)
Maximum dose rate during
continuous radiation
(at nominal voltage)
99.0 % saturation
10 Gy/s
99.5% saturation
5 Gy/s
Maximum dose per radiation
pulse (at nominal voltage)
99.0 % saturation
0.91 mGy
99.5 % saturation
0.46 mGy
Ion collection time (at nomi-
nal voltage)
140 µs
Polarity effect ≤ ±0.5 % at
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Directional response ≤ ±0.5 % for rotation around the detector axis
≤ ±0.5 % for tilting by ±5° perpendicular to the detector axis
Energy response ≤ ±2 % (70 ... 280) kV, reference 200 kV
≤ ±4 % (200 kV ...
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Transient periods for
temperature equilibrium
pressure equilibrium
(2 ... 3) min/K
≤ 10 s
Pre-irradiation none
Stabilization time The response after 15 minutes and 2 hours differs by less than ±0.5 %
from the value after 1 hour.
Post irradiation leakage signal drops to < 0.5 % within 5 s after irradiation
Stability long-term stability: ≤ ±0.5 % per year
dose stability: ≤ ±1 % per 10 kGy
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