Presentation on theme: "" Sampling the Universe above 10 keV""— Presentation transcript:
1 " Sampling the Universe above 10 keV" The Extreme Sky" Sampling the Universe above 10 keV" October 2009 OtrantoRecent Trends in the Development of CdTe and CdZnTe Semiconductor Detectors for Astrophysical ApplicationsS. Del Sordo1, L. Abbene1,2, N. Auricchio 1 ,E. Caroli1, M. Quadrini1, J.B. Stephen1 , A. Zappettini3, R.M. Curado Da Silva4, O. Limousin5, A. Meuris5 and P. Ubertini11IASF-INAF, Italy2DiFTeR Università di Palermo, Palermo, Italy3IMEM-CNR, Parma, Italy4Departmento de Física, Universidade de Coimbra, Coimbra, Portugal5CEA – DSM - Irfu - Service d’Astrophysique, Saclay, France
2 Outline Scenario (projects and collaborations) CdTe / CdZnTe X-ray and gamma ray detectorsDetector prototypesWork in progress and future developmentsConclusions
3 The Italian collaboration Projects and CollaborationsProgetto ASI Alte Energie (Study for the Gamma Ray Imager mission)Progetto PRIN INAF SGRIP (funded by INAF)Development of an high efficiency wide band 3D CZT detector prototype for Laue telescope focal planeProgetto PRIN (funded by MIUR)Growth technologies and spectroscopic optimization for X and Gamma ray detectors based on CdTe/CdZnTe.International collaborationsThe Italian collaborationESRF GrenobleLeicester UniversityDTU Space CopenaghenCoimbra UniversityCEA Saclay ParisICE-CSIC BarcelonaIASF-INAF (Milano Bologna Roma Palermo)IMEM-CNR di Parma (crystal growth)Università di Lecce (crystal growth and bonding)IMM-CNR di Lecce (bonding and electrical characterization)DIFTER Università di Palermo (medical applications)3
4 CdTe and CdZnTe I High Z semiconductors (Zmax = 52) Wide band gap semiconductorsDel Sordo S. et al., Sensors, Vol. 9, , 2009.
5 CdTe and CdZnTe II Critical Issues Poor transport properties of the charge carriers:hh ~ cm2/ Vee ~ cm2/V)Small electrical signals at the electrodesSmall crystal size: typically < 2 cm3Development of single charge carrier sensing detectors (pixel, strip, Frisch grid, multiple electrodes) to overcome the poor transport properties of the holes is mandatory.1 mmL. Abbene et al., NIM A 583 (2007)
6 A. Zappettini et al., IEEE Nucl. Sci. Symp. Conf. Rec. 2008, 118-121. CdTe and CdZnTe IIISuppliers of Spectrometer grade crystalsItalian group at IMEM-CNR (A. Zappettini): CdZnTe crystals grown by the boron oxide encapsulated vertical Bridgman technique1.1 mmA. Zappettini et al., IEEE Nucl. Sci. Symp. Conf. Rec. 2008,2-inch CdZnTe crystal
7 DETECTORS CHARACTERISTICS CdZnTe detector prototypesCZT pixel detectorsDETECTORS CHARACTERISTICSPixel detectorsCZT (eV Products)Geometric surface10×10 mm2Active area8×8 mm2Thickness1 mm and 2 mmNumber of pixels256Pitch0.5 mm(0.45 mm anodes, 0.05 mm gap)focal plane detector prototypes for Hard X-ray multilayer telescopes ( keV)
8 CZT pixel detectors performance CdZnTe detector prototypesCZT pixel detectors performanceEnergy (keV)Energy resolution (%)Peak to valley ratio (2 x FWHM)59.55.80 ± 0.1628.1 ± 1.188,13.9 ± 0.219.5 ± 1.1L. Abbene et al., JAP, Vol. 105, 2009.
9 CdZnTe detector prototypes CZT pixel detectors performance2 mm thick detector vs 1 mmthickness1 mm2 mmenergy resolution (%) (59.5 keV)5.80 ± 0.165.50 ± 0.10energy resolution (%) (88.1 keV)3.9 ± 0.23.50 ± 0.13deviation of the FW.1M/FWHM ratio from the Gaussian ratio (1.82) (59.5 keV)8 %5 %deviation of the FW.1M/FWHM ratio from the Gaussian ratio (1.82) (88.1 keV)16 %10 %“Small pixel effect”H. Barrett, J. Eskin, H. Barber, Phys. Rev. Lett. 75 (1995) 156
10 CdZnTe detector prototypes CZT pixel detector for the POLCA II Experiment (POLarimetry with CdZnTe Arrays)DetectorCZT Imarad4x4 cm2, 5 mm thickHV = -600 V16x16 pix with 2.5 mm pitch11x pix usedReadout Electronics8 eV products ASIC16 channels/chip33/50/100/200 sel. Gain0.6/1.2/2.4/4 μs shaping timeThe POLCA quick look S/W user interface (LABVIEW)
11 Counts maps (scattered events) CdZnTe detector prototypesPolca experiment: Set-up at ESRF beam line ID15B and ResultsCounts maps (scattered events)pixel 186, Energy 200 keV, Angle 0, 45 degree
12 CdZnTe detector prototypes Small 3D CZT position sensitive spectrometer (SmallGRIPrototype)3D detector prototype packaging scheme:The detector assembly is built with 8 identical modules packed together (64 anodes and 32 cathodes).I/O padsAlumina supportBasic sensitive CZT unit▶External Dimensions: 10×10×2.5 mm3Anode side: 8 anodes strips 0.15 mm wide(pitch=2.5 mm)correcting field strips 0.15 mm widegap between strips=0.15 mmCathode side: 4 cathodes strips 2.4 mm widegap between strips=0.10 mmFront end electronics boardRedout Electronics NOVARAD Rena3data handling and logic boardSee Poster E. Caroli et al. SGRIP …
14 Energy resolution 1.5 % (FWHM) @ 59.5 keV Future Developments The POLCaliste experimentPOLCaliste Experiment (POLarimetry with Caliste)Caliste module performanceEnergy resolution 1.5 % 59.5 keVT = -15 °CPolarimetric measurements at ESRF with the PolCaliste prototype are foreseen in We foresee to use in a first run the 64 ch device and in a next step the new 256 ch device. The device thickness will be 0.5, 1, 2 mm
15 Conclusions (I)Italian CZT detector development (crystal growth and detectors assembly) activities are in progress with quite good expectations.Experimental activities devoted to characterize imaging spectrometer operative in the keV energy band are in progress.The SGRIP experiment (considered as a pathfinder for GRI) is in an advanced realization phase. The study of the prototype performances, foreseen in the 2010, will allow the optimization of the main operative parameters for a detector operative up to 800 keV in stack configuration.The polarimetric performances of the POLCAII experiment are under evaluation. Measurements with the improved POLCaliste experiment are foreseen in the 2010 at ESRF.
16 Conclusions (II)Very recently ASI funded a technological project named :“LAUE - A Gamma Ray Lens”. In this project our collaboration has the responsibility of the focal plane detector (4 x 4 cm2 , 0.5 mm spatial resolution, good energy resolution) for the test of the lens prototypes. In this framework one of the most appealing possibilities will be the use of an array of Calliste detectors in the new 256 channel version.