A Comparative Study of Silicon Drift Detectors With Photomultipliers, Avalanche Photodiodes and PIN Photodiodes in Gamma Spectrometry With LaBr$_{3}$ Crystals

The investigated dual-range photon detector consists of an SDD which is optically coupled with a lanthanum bromide crystal. In contrast to similar configurations investigated by Fiorini et al. [6], the SDD side, not the scintillator side, points to the radiation source. Low-energy gammas or X rays are therefore absorbed in the bulk silicon and the SDD acts as a high-resolution detector on its own (Figure 1, left). siswitch detectors operate on this basis [CsI(TI) scintillator plus photodiode) [7], as well the dual-range photon detectors with CsI(TI) scintillators and photodiode [8] or SDD readout [9]. The proposed detector configuration combines for the first time a fast scintillator and a slow silicon detector. However, the pulse shape discrimination is successfully applied due to the long time required to collect the charge in the SDD, when the charge carriers are formed opposite to the anode (geometry effect). t Fig. 1: Scheme of the dual-range photon detector (DRPD) and illustration of the underlying detection modes. Low-energy gammas or X rays are absorbed in the SDD (l). The absorption process generates a local cloud of charge carriers. Electrons drift towards the anode (drift time to). The anode (A) signal is delayed just by to but shows a steep rise if the electron cloud arrives at the anode. Energetic gamma radiation mostly passes the SDD but might be absorbed in the scintillator (2).The SDD detects scintillation light. Photoelectrons are generated along the crystal-SDD contact zone. The superposition of contributions representing different drift paths and drift times results in a shallow anode signal. Pulse shape discrimination (PSD) separates the distinct detection mechanisms.This process is referred as to direct detection (SDD mode). More energetic radiation mostly passes the silicon layer but may be absorbed in the scintillator.The SDD then acts as an efficient photo detector for the scintillation light of those events. The scintillation flash illuminates the full contact area of SDD and crystal. The '1 (2) A '1 (1) qr toC, Abstract-Homeland security applications demand compact, high resolution detectors for gamma and X rays identification. Most commercial instruments use scintillating crystals or CdZnTe detectors. The identification performance is therefore intrinsically linked with the progress in developing crystals with a very high light output (LaBr3Ce or SrI 2 ) and with the manufacturing of the CdZnTe detectors. A new detector concept is proposed, which essentially improves on the existing resolution limits. It combines two distinct detection mechanisms in a compact, state-of-the-art solid-state detector, providing complementary information in different but overlapping energy ranges. The dual-range detector consists of a LaBr3(Ce3+) scintillator coupled to a silicon drift detector (SDD). The SDD serves as a high-resolution X-rayon its own, and in parallel as a light readout device for the LaBr3(Ce31 scintillator ensuring best possible resolution at higher energies.

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“…[10]. This is evidenced in Table II which compares experimental data obtained with the SDD-LaBr3 and with corresponding LaBr3-PMT combinations.…”

Section: - --------mentioning

confidence: 78%

“…The full potential of the SDD-LaBr3 crystal system was however not reached [10]. The continuous curves in the graph of the energy resolution versus energy in Fig.…”

Section: - --------mentioning

confidence: 96%

Prospects of a dual range photon detector with SDD and LaBr<inf>3</inf>(Ce) scintillator

Plettner¹,

Pausch²,

Herbach³

et al. 2008

2008 IEEE Nuclear Science Symposium Conference Record

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“…This is apparently correlated with the optical coupling, i.e., with the accuracy of the crystal mounting and the optical contact. An estimate of the effective quantum efficiency according to (3) with the absolute light output taken from Table I results in a value of about 55% for the best coupling [14], [19].…”

Section: B Signal Shaping Ballistic Deficit and Energy Resolutionmentioning

confidence: 99%

“…The reduced noise contribution of the SDD obviously over-compensates the worse photoelectron statistics due to incomplete charge collection. A detailed analysis is given in [14], [19].…”

Section: B Signal Shaping Ballistic Deficit and Energy Resolutionmentioning

confidence: 99%

Demonstration of a Dual-Range Photon Detector With SDD and ${\hbox {LaBr}}_{3}({\hbox {Ce}}^{3+})$ Scintillator

Pausch

Plettner

Herbach

et al. 2009

IEEE Trans. Nucl. Sci.

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A novel concept for improving gamma ray spectroscopy in compact instruments is presented. The dual-range photon detector (DRPD) consists of a silicon drift detector (SDD) which is optically coupled with a LaBr 3 (Ce 3+ ) crystal. In contrast to similar configurations investigated so far the SDD points to the radiation source. Pulse shape discrimination allows separating the distinct detection mechanisms which correspond to gamma absorption in the SDD or in the scintillator, respectively. This arrangement combines for the first time the excellent performance of an SDD as X-ray detector on its own with the striking energy resolution of a LaBr 3 (Ce 3+ ) scintillator read out by an SDD. The concept was successfully demonstrated with two experimental SDD-LaBr 3 (Ce 3+ ) systems. An energy resolution (FWHM) of 2.7% and 2.9% at 662 keV was measured with the two distinct systems operated in scintillator mode whereas scintillator-photomultiplier combinations with the same crystals yielded only 3.3% and 3.1%, respectively. The SDD mode provided an energy resolution surpassing the scintillator resolution by about one order of magnitude in the limited energy range up to 100 keV. Measurements with various radioactive sources demonstrated that this mode uncovers line structures which could never be resolved with scintillators or CZT detectors. Homeland security programs could profit from the proposed detector concept.

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“…This feature allows reaching a low electronics noise, making it an ideal device for X-ray spectroscopy applications [2], but also a competitive device for scintillator readout representing a valid alternative to conventional photomultiplier tube (PMT) [3][4][5][6][7]. SDDs show high quantum efficiency and a low intrinsic electronics noise.…”

Section: Introductionmentioning

confidence: 99%

New development of Silicon Drift Detectors for gamma-ray spectroscopy

Fiorini

Bombelli

Busca

et al. 2012

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)

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In this work, we report on a new development of Silicon Drift Detectors (SDDs) for gamma-ray spectroscopy for astronomy applications, within a research project supported by the European Space Agency. The final goal of the development is the realization of monolithic arrays of SDDs which will be assembled to readout large (2″×2″ and 3″×3″) LaBr3 scintillators. We report on the development of a new single SDD prototype, with 8×8 mm2 active area, produced at FBK semiconductor laboratories. For the readout of the SDD signals,we have adopted a CMOS charge preamplifier (CUBE) recently developed at Politecnico di Milano. This preamplifier has allowed to achieve state-of-the-art noise performance using a relatively standard SDD technology process. A quantum efficiency of about 80% has been measured on the SDD at the emission wavelengths of LaBr3 (360–380 nm). In first experimental measurements irradiating the SDD, without scintillator, with a 55Fe source we achieved an energy resolution of 140eV and 129eV, respectively, at −20°C and −43°C. By coupling the SDD with a LaBr3 scintillator (9mm diameter), we have measured an energy resolution of 5.6% FWHM and 2.6% FWHM respectively at 122keV and 662keV

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A Comparative Study of Silicon Drift Detectors With Photomultipliers, Avalanche Photodiodes and PIN Photodiodes in Gamma Spectrometry With LaBr$_{3}$ Crystals

Cited by 26 publications

References 23 publications

Prospects of a dual range photon detector with SDD and LaBr<inf>3</inf>(Ce) scintillator

Prospects of a dual range photon detector with SDD and LaBr<inf>3</inf>(Ce) scintillator

Demonstration of a Dual-Range Photon Detector With SDD and ${\hbox {LaBr}}_{3}({\hbox {Ce}}^{3+})$ Scintillator

New development of Silicon Drift Detectors for gamma-ray spectroscopy

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