AG Hofsäss - II- Institute of Physics
Gamma spectroscopy
We have several Germanium semiconductor detectors available for high resolution energy resolved gamma spectroscopy.
We can identify most gamma radiation emitting radioactive isotopes using professional data acquisition hardware and analysis software.
We have a number of large NaI(Tl) scintillation detectors available which allow the detection of low level radioactivity.
Ge- Detectors:
- ORTEC GEM-70205-P-S PopTop, rel efficiency 65%, 10 cm lead shielding, sample volume 250-750 cm3
- ORTEC GMX-15190-S , rel efficiency 15%, 10 cm lead shielding, sample volume 100 cm3
- Canberra 7229 P Model 7600SL, rel. efficiency 15%
- ORTEC GEM coaxial P-type HPGE GEM70, rel. efficiency 15%
- ORTEC GEM-18180, rel efficiency 21 %
- ORTEC 2112-09190.S, rel efficiency 9 %
(the relative efficiency is given in comparison to a 3x3 inch NaI detector)
Low level measurements of environmental radioactivity and radioactive contaminations
Examples:
analysis of Cs-137 (661 keV) and I-131 (364 keV) sensitivity 0.15 Bq/liter
unrestricted clearance limit 100 Bq/kg
limit for food < 600 Bq/kg
analysis of Co-60 (1100-1300 keV) sensitivity: 0.01 Bq per sample
unrestricted clearance limit: 0.1 Bq/g
analysis of natural potassium K-40 (1461 keV)sensitivity 15-40 Bq/liter
1 kg Soy flour: 1450 Bq
daily recommended potassium intake: 4 g potassium or 2580 Bq
analysis of Pb-210 (46 keV)
analysis of decay products from Uranium and Thorium decay
Our large NaI(Tl) scintillation detectors are used for the detection of low level radioactivity
- down to 2.5 Bq/l or 0.002 Bq per gramm for Co-60 in steel or iron
- down to 0.1 Bq per kilogramm or liter for Cs-137 , I-131 and K-40
We use:
- One 5x5 inch NaI(Tl) borehole detector for 25 cm3 volume samples,
rel. efficiency 460%, 10 cm lead shielding
- One 4x4 inch NaI(Tl) borehole detector for 15 cm3 volume samples,
rel. efficiency 226%, 10 cm lead shielding
- Two 4x4 inch NaI(Tl) detectors with up to 3 liter Marinelli cups for analysis of liquid samples,
rel. efficiency 237 %, 10 cm lead shielding
- One 2x2 inch NaI(Tl) detector with 750 ml Marinelli cup for analysis of liquid samples
rel efficiency 30 %, 10 cm lead shielding
- One 6x8 inch inch NaI(Tl) borehole detector for 750 cm3 volume samples,
rel. efficiency 1200 %, 10 cm lead shielding
- Three 5x5 inch NaI(Tl) detectors, rel. efficiency 460 %
Detection of cosmic muons using six large 6x9 inch NaI scintillation detectors
- Each of the scintillators detecs between 6 and 10 Muons/second.
- Energy loss of muons can be measured
- Angular distribution of incoming muons can be measured
- Data acquisition using a PC sound card
