Study of cadmium zinc telluride (CZT) radiation detector modules under moderate and long-term variations of temperature and humidity

Mashlum, G.; Dietzel, Knut Ingvald; Meier, Dirk; Szawłowski, M.; Sundal, B.; Vandehei, T.; Wagenaar, Douglas J.; Patt, Bradley E.

doi:10.1109/nssmic.2007.4437315

Cited by 6 publications

(5 citation statements)

References 4 publications

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“…The 241 Am spectrum has a photo peak at 59.5 keY and entries about 23 keY and 27 keY below the photo peak due to x-ray escape from Cd and Te, respectively. For the 59.5-keV photo peak we measure about 4-keV full-width-half-maximum (FWHM) , which is better than previous measurements with the same type of CZT but different readout [17]. A measurement with all CZT pixels connected to the readout but without any charge from radiation gives the pedestal [ Fig.…”

Section: Tra Nsformation Of Random Numbersmentioning

confidence: 95%

Interpolation in a pixellated CZT γ-radiation detector

Meier¹,

Gheorghe²,

Johansen³

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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We describe a method of interpolation for a pixel lated ,,(-radiation detector made of cadmium zinc telluride (CZT) with the goal to optimize its intrinsic spatial resolution. A similar method is known from silicon strip sensors where the interpolation improves the intrinsic spatial resolution over the single-strip digital resolution.We used a CZT crystal with a 2-dimensional matrix of anodes (pixels) on one side and a cathode on the other side. Each anode was electrically connected to a charge sensitive amplifier/shaper, which provided a pulse height output proportional to the amount of the electrical charge induced at the anodes. The amplifiers were implemented in a custom made application specific integrated circuit (ASIC) that allowed us to read out the charge from the triggering pixel and, in addition, the charge from its nearest neighbour pixels. We used 241 Am, 57 Co and 22 Na radiation sources to acquire energy spectra and shadow images from a tungsten metal edge.We observed charge sharing between pixels in about 10%and 24% of the photon interactions for 59.5 keV and 122 keV, respectively. We found that the method of interpolation did not improve the intrinsic spatial resolution in the CZT detector used, presumably due to the very small gap between pixels.Nevertheless, we consider interpolation important, since it has the potential to improve intrinsic spatial resolution either with a different method or with an anode layout that allows for more charge sharing, e.g., with larger gaps between pixels. Like in silicon sensors the method may benefit from additional electrodes in the gaps between the readout pixels.

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Section: Tra Nsformation Of Random Numbersmentioning

confidence: 95%

Interpolation in a pixellated CZT γ-radiation detector

Meier¹,

Gheorghe²,

Johansen³

et al. 2011

2011 IEEE Nuclear Science Symposium Conference Record

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“…The use of soft bonds, such as indium bump bonds, has been fairly successful, though an underfill of epoxy seems necessary to prevent eventual delamination. The long-term stability of CZT detectors with temperature and humidity variations has been studied, and not found to be a problem under moderate conditions (Maehlum et al, 2007). …”

Section: Advances In Semiconductor Readoutmentioning

confidence: 99%

SPECT detectors: the Anger Camera and beyond

2011

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The development of radiation detectors capable of delivering spatial information about gamma-ray interactions was one of the key enabling technologies for nuclear medicine imaging and, eventually, single-photon emission computed tomography (SPECT). The continuous NaI(Tl) scintillator crystal coupled to an array of photomultiplier tubes, almost universally referred to as the Anger Camera after its inventor, has long been the dominant SPECT detector system. Nevertheless, many alternative materials and configurations have been investigated over the years. Technological advances as well as the emerging importance of specialized applications, such as cardiac and preclinical imaging, have spurred innovation such that alternatives to the Anger Camera are now part of commercial imaging systems. Increased computing power has made it practical to apply advanced signal processing and estimation schemes to make better use of the information contained in the detector signals. In this review we discuss the key performance properties of SPECT detectors and survey developments in both scintillator and semiconductor detectors and their readouts with an eye toward some of the practical issues at least in part responsible for the continuing prevalence of the Anger Camera in the clinic.

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“…The cross-strip electrode pattern was chosen to provide high spatial resolution for x – y localization of photon interactions while using fewer electronic channels compared to standard square pixel designs e.g. Mashlum et al (2007), that is, 2 n versus n 2 .…”

Section: The Czt Detector Designmentioning

confidence: 99%

“…localization of photon interactions while using fewer electronic channels compared to standard square pixel designs e.g. Mashlum et al (2007), that is, 2n versus n 2 . In the prototype, seven cathodes span the one face of the CZT crystal (figure 2(a)).…”

Section: Cadmium Zinc Telluride Crystal As An Annihilation Photon Det...mentioning

confidence: 99%

Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET

Matteson

Skelton

et al. 2011

Phys. Med. Biol.

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This paper investigates the performance of 1 mm resolution Cadmium Zinc Telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3-D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06±0.39% at 511 keV throughout most the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44±0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78±0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes – as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system.

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Study of cadmium zinc telluride (CZT) radiation detector modules under moderate and long-term variations of temperature and humidity

Cited by 6 publications

References 4 publications

Interpolation in a pixellated CZT γ-radiation detector

Interpolation in a pixellated CZT γ-radiation detector

SPECT detectors: the Anger Camera and beyond

Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET

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Study of cadmium zinc telluride (CZT) radiation detector modules under moderate and long-term variations of temperature and humidity

Cited by 6 publications

References 4 publications

Interpolation in a pixellated CZT &#x03B3;-radiation detector

Interpolation in a pixellated CZT &#x03B3;-radiation detector

SPECT detectors: the Anger Camera and beyond

Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET

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Product

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Interpolation in a pixellated CZT γ-radiation detector

Interpolation in a pixellated CZT γ-radiation detector