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

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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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