23/07/2010 1Student Practice in JINR Fields of Research - HPGe detectors technologies
Participants:• Agnieszka Kapelak , UAM Poznań• Michalina Komorowska, UW Warszawa• Paulina Staszewska, UAM Poznań
Supervisor:mgr inż. Dariusz Borowicz, IFJ PAN Kraków, DLNP JINR
Experimental Research Department of Nuclear Spectroscopy and
Radiochemistry
23/07/2010 2Student Practice in JINR Fields of Research - HPGe detectors technologies
• ƴ - ray spectroscopy • Nuclear medicine• Environmental
monitoring
• Very good energy resolution
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Variety of HPGe cryostats and Dewar vessels
• For detecting low energies• ≤ 150 keV
• Applied for polarization measurments
• Small electrical capacitance• example 2 pF for X-rays
detectors (typically 16 mm diameter and 5 mm thick)
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• For higher energies, up to several MeV
• Larger values of electrical capacitance ̴20 pF
• Commonly used crystal size - 6 cm in diameter
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Cutting the crystal, making of the p-n junction
Cutting out the protecion ring
Evaporation of Au on p-n juntion side
23/07/2010 8Student Practice in JINR Fields of Research - HPGe detectors technologies
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Etching and oxidizing for an ohmic contact.
Temperature evaporation of Pd and Au upon a prepared surface.
Final etching and protecting the surface from the environment.
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• The higher possible voltage value, the better charge collection and better time resolution
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Voltage – Current characteristic
Voltage – Capacity characteristic
• U₀ - voltage value for which the full volume of the detector is active
Energy resolution measurments for HPGe
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241Am
FWHM 238eV
0
500
1000
1500
2000
2500
3000
5 10 15 20 25 30
E[keV]
l.zliczen
23/07/2010 13Student Practice in JINR Fields of Research - HPGe detectors technologies
• Dr Stanislav Z. Pakuliak (BLTP JINR, Dubna) • Dr Władysław Chmielowski (JINR, Dubna)• Dr hab. Roman Zawodny (UAM, Poznań)• mgr inż. Dariusz Borowicz (IFJ, Kraków / JINR, Dubna)
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