Digital fast pulse shape and height analysis on cadmium-zinc-telluride arrays for high-flux energy-resolved X-ray imaging.

Title Digital fast pulse shape and height analysis on cadmium-zinc-telluride arrays for high-flux energy-resolved X-ray imaging.
Authors L. Abbene; F. Principato; G. Gerardi; M. Bettelli; P. Seller; M.C. Veale; N. Zambelli; G. Benassi; A. Zappettini
Journal J Synchrotron Radiat
DOI 10.1107/S1600577517015697
Abstract

Cadmium-zinc-telluride (CZT) arrays with photon-counting and energy-resolving capabilities are widely proposed for next-generation X-ray imaging systems. This work presents the performance of a 2?mm-thick CZT pixel detector, with pixel pitches of 500 and 250?µm, dc coupled to a fast and low-noise ASIC (PIXIE ASIC), characterized only by the preamplifier stage. A custom 16-channel digital readout electronics was used, able to digitize and process continuously the signals from each output ASIC channel. The digital system performs on-line fast pulse shape and height analysis, with a low dead-time and reasonable energy resolution at both low and high fluxes. The spectroscopic response of the system to photon energies below (109Cd source) and above (241Am source) the K-shell absorption energy of the CZT material was investigated, with particular attention to the mitigation of charge sharing and pile-up. The detector allows high bias voltage operation (>5000?V?cm-1) and good energy resolution at moderate cooling (3.5% and 5% FWHM at 59.5?keV for the 500 and 250?µm arrays, respectively) by using fast pulse shaping with a low dead-time (300?ns). Charge-sharing investigations were performed using a fine time coincidence analysis (TCA), with very short coincidence time windows up to 10?ns. For the 500?µm pitch array (250?µm pitch array), sharing percentages of 36% (52%) and 60% (82%) at 22.1 and 59.5?keV, respectively, were measured. The potential of the pulse shape analysis technique for charge-sharing detection for corner/border pixels and at high rate conditions (250?kcps?pixel-1), where the TCA fails, is also shown. Measurements demonstrated that significant amounts of charge are lost for interactions occurring in the volume of the inter-pixel gap. This charge loss must be accounted for in the correction of shared events. These activities are within the framework of an international collaboration on the development of energy-resolved photon-counting systems for high-flux energy-resolved X-ray imaging (1-140?keV).

Citation L. Abbene; F. Principato; G. Gerardi; M. Bettelli; P. Seller; M.C. Veale; N. Zambelli; G. Benassi; A. Zappettini.Digital fast pulse shape and height analysis on cadmium-zinc-telluride arrays for high-flux energy-resolved X-ray imaging.. J Synchrotron Radiat. 2018;25(Pt 1):257271. doi:10.1107/S1600577517015697

Related Elements

Cadmium

See more Cadmium products. Cadmium (atomic symbol: Cd, atomic number: 48) is a Block D, Group 12, Period 5 element with an atomic weight of 112.411. Cadmium Bohr ModelThe number of electrons in each of Cadmium's shells is 2, 8, 18, 18, 2 and its electron configuration is [Kr]4d10 5s2. The cadmium atom has a radius of 151 pm and a Van der Waals radius of 230 pm. Cadmium was discovered and first isolated by Karl Samuel Leberecht Hermann and Friedrich Stromeyer in 1817. In its elemental form, cadmium has a silvery bluish gray metallic appearance. Cadmium makes up about 0.1 ppm of the earth's crust. Elemental CadmiumNo significant deposits of cadmium containing ores are known, however, it is sometimes found in its metallic form. It is a common impurity in zinc ores and is isolated during the production of zinc. Cadmium is a key component in battery production and particular pigments and coatings due to its distinct yellow color. Cadmium oxide is used in phosphors for television picture tubes. The name Cadmium originates from the Latin word 'cadmia' and the Greek word 'kadmeia'.

Zinc

See more Zinc products. Zinc (atomic symbol: Zn, atomic number: 30) is a Block D, Group 12, Period 4 element with an atomic weight of 65.38. The number of electrons in each of zinc's shells is 2, 8, 18, 2, and its electron configuration is [Ar] 3d10 4s2. Zinc Bohr ModelThe zinc atom has a radius of 134 pm and a Van der Waals radius of 210 pm. Zinc was discovered by Indian metallurgists prior to 1000 BC and first recognized as a unique element by Rasaratna Samuccaya in 800. Zinc was first isolated by Andreas Marggraf in 1746. In its elemental form, zinc has a silver-gray appearance. It is brittle at ordinary temperatures but malleable at 100 °C to 150 °C.Elemental Zinc It is a fair conductor of electricity, and burns in air at high red producing white clouds of the oxide. Zinc is mined from sulfidic ore deposits. It is the 24th most abundant element in the earth's crust and the fourth most common metal in use (after iron, aluminum, and copper). The name zinc originates from the German word "zin," meaning tin.

Tellurium

See more Tellurium products. Tellurium (atomic symbol: Te, atomic number: 52) is a Block P, Group 16, Period 5 element with an atomic radius of 127.60. Tellurium Bohr ModelThe number of electrons in each of tellurium's shells is 2, 8, 18, 18, 6 and its electron configuration is [Kr] 4d10 5s2 5p4. Tellurium was discovered by Franz Muller von Reichenstein in 1782 and first isolated by Martin Heinrich Klaproth in 1798. In its elemental form, tellurium has a silvery lustrous gray appearance. The tellurium atom has a radius of 140 pm and a Van der Waals radius of 206 pm. Elemental TelluriumTellurium is most commonly sourced from the anode sludges produced as a byproduct of copper refining. The name Tellurium originates from the Greek word Tellus, meaning Earth.

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