Therapy Detectors Roos Chamber - JRT Associatesjrtassociates.com/pdfs/ptw_roos.pdf · Therapy...
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Therapy Detectors 21 Roos Chamber Type 34001 Waterproof plane parallel chamber for absolute dosimetry in high-energy electron and proton beams Features Perturbation-free, minimized polarity effect Waterproof, wide guard ring design Sensitive volume 0.35 cm 3 , vented to air Radioactive check device (option) The 34001 Roos chamber is the golden standard for absolute dose measurements in high-energy electron beams. Modern dosimetry protocols refer to the cham- ber's design and provide dosimetric correction factors. Its waterproof design allows the chamber to be used in water or in solid state phantoms. The Roos chamber is also well suited for the measurement of high-energy photon depth dose curves up to 2.5 mm below the water surface. The chamber can be used for dose meas- urements of proton beams. Specification Type of product vented plane parallel ionization chamber acc. IEC 60731 Application absolute dosimetry in high-energy electron and proton beams Measuring quantity absorbed dose to water Reference radiation 60 Co quality Nominal sensitive 0.35 cm 3 volume Design waterproof, vented Reference point in chamber center, 1.12 mm below surface Direction of incidence perpendicular to chamber plane, see label 'Focus' Nominal response 12 nC/Gy Long-term stability ≤ 0.5 % per year Chamber voltage 200 V nominal ± 400 V maximal Polarity effect < 0.5 % Directional response in ≤ ± 0.1 % for chamber water tilting ≤ ± 10° Leakage current ≤ ± 4 fA Cable leakage ≤ 1 pC/(Gy·cm) Materials and measures: Entrance window 1 mm PMMA, 1.19 g/cm 3 0.02 mm graphite, 0.82 g/cm 3 0.1 mm varnish, 1.19 g/cm 3 Total window area density 132 mg/cm 2 Water-equivalent window 1.3 mm thickness Sensitive volume radius 7.5 mm depth 2 mm Guard ring width 4 mm Ion collection efficiency at nominal voltage: Ion collection time 125 μs Max. dose rate for ≥ 99.5 % saturation 5.2 Gy/s ≥ 99.0 % saturation 10.4 Gy/s Max. dose per pulse for ≥ 99.5 % saturation 0.46 mGy ≥ 99.0 % saturation 0.93 mGy Useful ranges: Chamber voltage ± (50 ... 300) V Radiation quality (2 ... 45) MeV electrons 60 Co ... 25 MV photons (50 ... 270) MeV protons Field size (4 x 4) cm 2 ... (40 x 40) cm 2 Temperature (10 ... 40) °C (50 ... 104) °F Humidity (10 ... 80) %, max 20 g/m 3 Air pressure (700 ... 1060) hPa Ordering Information TN34001 Roos electron chamber 0.35 cm 3 , connecting system BNT TW34001 Roos electron chamber 0.35 cm 3 , connecting system TNC TM34001 Roos electron chamber 0.35 cm 3 , connecting system M Options T48010 Radioactive check device 90 Sr T48004 Chamber holding device for check device
Transcript of Therapy Detectors Roos Chamber - JRT Associatesjrtassociates.com/pdfs/ptw_roos.pdf · Therapy...
Therapy Detectors
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Roos ChamberType 34001
Waterproof plane parallel chamber forabsolute dosimetry in high-energy electron and proton beams
FeaturesPerturbation-free, minimized polarity effect
Waterproof, wide guard ring design
Sensitive volume 0.35 cm3, vented to air
Radioactive check device (option)
The 34001 Roos chamber is the golden standard forabso lute dose measurements in high-energy electronbeams. Modern dosimetry protocols refer to the cham-ber's design and provide dosimetric correction factors. Itswaterproof design allows the chamber to be used inwater or in solid state phantoms. The Roos chamber isalso well suited for the measurement of high-energyphoton depth dose curves up to 2.5 mm below thewater surface. The chamber can be used for dose meas-urements of proton beams.
SpecificationType of product vented plane parallel
ionization chamber acc. IEC 60731
Application absolute dosimetry in high-energy electron andproton beams
Measuring quantity absorbed dose to water
Reference radiation 60Coquality
Nominal sensitive 0.35 cm3
volume
Design waterproof, vented
Reference point in chamber center, 1.12 mm below surface
Direction of incidence perpendicular to chamberplane, see label 'Focus'
Nominal response 12 nC/Gy
Long-term stability ≤ 0.5 % per year
Chamber voltage 200 V nominal± 400 V maximal
Polarity effect < 0.5 %
Directional response in ≤ ± 0.1 % for chamber water tilting ≤ ± 10°
Leakage current ≤ ± 4 fA
Cable leakage ≤ 1 pC/(Gy·cm)
Materials and measures:Entrance window 1 mm PMMA, 1.19 g/cm3
0.02 mm graphite, 0.82 g/cm3
0.1 mm varnish, 1.19 g/cm3
Total window area density 132 mg/cm2
Water-equivalent window 1.3 mmthickness
Sensitive volume radius 7.5 mmdepth 2 mm
Guard ring width 4 mm
Ion collection efficiency at nominal voltage:Ion collection time 125 µs
Max. dose rate for≥ 99.5 % saturation 5.2 Gy/s≥ 99.0 % saturation 10.4 Gy/s
Max. dose per pulse for≥ 99.5 % saturation 0.46 mGy≥ 99.0 % saturation 0.93 mGy
Useful ranges:Chamber voltage ± (50 ... 300) V
Radiation quality (2 ... 45) MeV electrons60Co ... 25 MV photons(50 ... 270) MeV protons
Field size (4 x 4) cm2 ... (40 x 40) cm2
Temperature (10 ... 40) °C(50 ... 104) °F
Humidity (10 ... 80) %, max 20 g/m3
Air pressure (700 ... 1060) hPa
Ordering InformationTN34001 Roos electron chamber 0.35 cm3,
connecting system BNT
TW34001 Roos electron chamber 0.35 cm3,connecting system TNC
TM34001 Roos electron chamber 0.35 cm3,connecting system M
OptionsT48010 Radioactive check device 90Sr T48004 Chamber holding device for check device
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This product is available through JRT Associates 800-221-0111
