Silicon Drift Chamber Research Articles

Elemental mapping in a contemporary miniature by full-field X-ray fluorescence imaging with gaseous detector vs. scanning X-ray fluorescence imaging with polycapillary optics

Energy dispersive X-ray imaging can be used in several research fields and industrial applications. Elemental mapping through energy dispersive X-ray imaging technique has become a promising method to obtain positional distribution of specific elements in a non-destructive way. To obtain the elemental distribution of a sample it is necessary to use instruments capable of providing a precise positioning together with a good energy resolution. Polycapillary beams together with silicon drift chamber detectors are used in several commercial systems and are considered state-of-the-art spectrometers, however they are usually very costly. A new concept of large energy dispersive X-ray imaging systems based on gaseous radiation detectors emerged in the last years enabling a promising 2D elemental detection at a very reduced price. The main goal of this work is to analyze a contemporary Indian miniature with both X-ray fluorescence imaging systems, the one based on a gaseous detector 2D-THCOBRA and the state-of-the-art spectrometer M4 Tornado, from Bruker. The performance of both systems is compared and evaluated in the context of the sample's analysis.

Beyond the Great Wall: Gold of the Silk Roads and the First Empire of the Steppes

Fingerprinting ancient gold work requires the use of nondestructive techniques with high spatial resolution (down to 25 μm) and good detection limits (micrograms per gram level). In this work experimental setups and protocols for synchrotron radiation induced X-ray fluorescence (SRXRF) at the BAMline of the Berlin electron storage ring company for synchrotron radiation (BESSY) in Berlin for the measurement of characteristic trace elements of gold are compared considering the difficulties, shown in previous works, connected to the quantification of Pt. The best experimental conditions and calculation methods were achieved by using an excitation energy of 11.58 keV, a silicon drift chamber detector (SDD) detector, and pure element reference standards. A detection limit of 3 μg/g has been reached. This newly developed method was successfully applied to provenancing the Xiongnu gold from the Gol Mod necropolis, excavated under the aegis of the United Nations Educational, Scientific and Cultural Organization (UNESCO). The composition of the base alloys and the presence of Pt and Sn showed that, contrary to what is expected, the gold foils from the first powerful empire of the steppes along the Great Wall were produced with alluvial gold from local placer deposits located in Zaamar, Boroo, and in the Selenga River.

Keeping Capacitance Small: The Quest to Integrate Electronics on High-Resistivity, Fully Depleted Detectors

It was 1983 when the first experimental result proved that it was possible to produce a semiconductor detector of virtually any area (even as big as a wafer) and sensitive throughout the whole volume but with a tiny, low-capacitance collecting electrode. The device was fully depleted of carriers, as in a reverse junction single diode but through the full wafer thickness, and the generated carriers are drifted in a controlled way toward the collecting electrode. At that time, the device was called a silicon drift chamber (SDC), and it was the realization of a long-pursued dream of the scientists working in the detector field: to create a large detector, simple in operation, but still able to take advantage of the highest possible energy resolution obtainable through such a low-capacitance contact. This class of detectors, allowing position reconstruction of the interaction event with micrometer position resolution and precise charge reconstruction of the released energy within a few electrons, is indeed one of the greatest achievements of the career of Emilio Gatti and the best product of his deep and fruitful scientific and personal collaboration with Pavel Rehak of Brookhaven National Laboratory in Upton, New York.

MIXS on BepiColombo and its DEPFET based focal plane instrumentation

Focal plane instrumentation based on DEPFET Macropixel devices, being a combination of the Detector–Amplifier structure DEPFET with a silicon drift chamber (SDD), has been proposed for the MIXS (Mercury Imaging X-ray Spectrometer) instrument on ESA's Mercury exploration mission BepiColombo. MIXS images X-ray fluorescent radiation from the Mercury surface with a lightweight X-ray mirror system on the focal plane detector to measure the spatially resolved element abundance in Mercury's crust. The sensor needs to have an energy resolution better than 200 eV FWHM at 1 keV and is required to cover an energy range from 0.5 to 10 keV, for a pixel size of 300 × 300 μ m 2 . Main challenges for the instrument are radiation damage and the difficult thermal environment in the mercury orbit. The production of the first batch of flight devices has been finished at the MPI semiconductor laboratory. Prototype modules have been assembled to verify the electrical properties of the devices; selected results are presented here. The prototype devices, Macropixel prototypes for the SIMBOL-X focal plane, are electrically fully compatible, but have a pixel size of 0.5×0.5 mm 2. Excellent homogeneity and near Fano-limited energy resolution at high readout speeds have been observed on these devices.

Measurement of the Current Related Damage Rate at ${-}50^\circ$C and Consequences on Macropixel Detector Operation in Space Experiments

A diode irradiation with 10-MeV protons was performed to measure the silicon current related damage rate at a temperature of -50°C. This measurement was fundamental to predict the performance of the detectors which will be used in the X-ray spectrometers of the Simbol-X and BepiColombo space missions. These detectors consist of arrays of large area silicon drift chambers with integrated depleted p-channel field effect transistors. The leakage current increase due to radiation damage and its consequent energy resolution degradation can be critical for these missions, specially for BepiColombo. These effects cannot be predicted because, during the whole missions, the sensors will be kept at temperatures below -40°C, and the existing models are based on measurements on structures which underwent annealing at higher temperatures. An irradiation experiment was performed to measure the current related damage rate at - 50°C, and the obtained value was (11.1 ± 0.2) X 10-17 A/cm. This result implies that it will be possible to achieve the Simbol-X energy resolution, whereas some annealing strategies will be needed for the BepiColombo mission. The annealing behaviour at 60°C was studied as well and the results are in agreement with the already available measurements.

A pulse shape discrimination gamma-ray detector based on a silicon drift chamber coupled to a CsI(Tl) scintillator: prospects for a 1 keV-1 MeV monolithic detector

In this paper, an X- and gamma-ray detector based on a silicon drift detector (SDD) coupled to a CsI(Tl) scintillating crystal is presented. The SDD is operated both as a direct X-ray detector for photons interacting in silicon and as an indirect detector for photons interacting in the scintillator. As interactions in silicon and in CsI yield different amounts of charge per unit energy deposited, discrimination of the place of interaction is necessary to obtain the correct energy. Discrimination of the interaction type is carried out by means of pulse shape discrimination performed with two parallel processing chains with different shaping times. The performance of the detectors are described and discussed. Pulse shape discrimination is possible throughout the detector energy range.

Preliminary results from the 2000 run of CERES on low-mass e+e− pair production in Pb–Au collisions at 158 A GeV

CERES has measured low-mass e+e− pairs in Pb–Au collisions at 158 A GeV in the year 2000 Pb run at the SPS with the goal of shedding more light on the origin of the previously observed low-mass pair enhancement. The spectrometer was upgraded with a radial TPC to improve the mass resolution. A very effective rejection of the combinatorial background is achieved using the combined information of the two RICH detectors, the dE/dx signal of the doublet of silicon drift chambers, and the TPC track dE/dx information. Various steps and the current status of the data analysis are presented.Corrigendum. Table 1 and figures 3 and 4, as originally published, represent an earlier version of the data analysis. The corrected table and figures have been published as a Corrigendum (see below). The Corrigendum has also been appended at the end of the PDF file linked to this page.

Analysis of Limoges painted enamels from the 16th to 19th centuries by using a portable micro x‐ray fluorescence spectrometer

AbstractMaterial analysis of Limoges painted enamels was undertaken by using an x‐ray fluorescence spectrometer equipped with a low‐power x‐ray tube, polycapillary x‐ray optics and a silicon drift chamber detector. The spectrometer, which includes helium purging for detecting elements down to sodium, can easily be assembled and dismantled within 1 h. A quantification method for enamel and glass objects was developed and verified using standard materials. The layer arrangement and possible influence on the XRF measurements were especially considered in theoretical calculations. Over 160 painted enamels from the late Renaissance and Revival periods in the 19th century in various collections were investigated. Comparison of the quantitative results from objects which are securely dated and attributed by art historians allowed a more reliable attribution of pieces with doubted authenticity. Copyright © 2004 John Wiley & Sons, Ltd.

Hybrid photon detectors

Abstract Hybrid photon detectors detect light via vacuum photocathodes and accelerate the emitted photoelectrons by an electric field towards inversely polarized silicon anodes, where they are absorbed, thus producing electron–hole pairs. These, in turn, are collected and generate electronic signals on their ohmic contacts. This review first describes the characteristic properties of the main components of hybrid photon detectors: light entrance windows, photocathodes, and silicon anodes. Then, essential relations describing the trajectories of photoelectrons in electric and magnetic fields and their backscattering from the silicon anodes are derived. Depending on their anode configurations, three families of hybrid photon detectors are presented: hybrid photomultiplier tubes with single anodes for photon counting with high sensitivity and for gamma spectroscopy; multi-anode photon detector tubes with anodes subdivided into square or hexagonal pads for position-sensitive photon detection; imaging silicon pixel array tubes with finely segmented anodes for photon-sensitive imaging devices. Some of the hybrid photon detectors’ applications and achievements in radiation detection are discussed and compared with competing devices such as photomultipliers, image intensifiers, photodiodes, silicon drift chambers, charge coupled devices, visible light photon counters, and photographic emulsions.

Position and energy resolution of a new gamma-ray detector based on a single CsI(Tl) scintillator coupled to a silicon drift chamber array

We have developed a first prototype of gamma-ray detector for imaging and spectroscopy which is based on a single CsI(Tl) scintillator coupled to a linear array of silicon drift chambers (SDCs). The detector performs the measurement of the position of interaction in one coordinate, by the centroid method, and the measurement of the /spl gamma/ photon energy, by summing the signals of all the single units. The small size and the compactness of the CsI(Tl)-SDC assembly make this detector scheme an interesting solution for the realization of small scintillation cameras for nuclear medicine. Moreover, the low electronics noise offered by the SDC allows to reach good performances in both position and energy resolution. The first experimental results obtained on the prototype are reported in this work. A position resolution better than 1 mm FWHM and an energy resolution of about 16% FWHM at 122 keV have been measured. A comparison of the experimental results with the results of Monte Carlo simulations is also reported.

Performances of a silicon drift chamber as fast scintillator photodetector for gamma-ray spectroscopy

The performances of a Silicon Drift Chamber (SDC), having a diameter of 3 mm, as scintillation light photodetector have been experimentally evaluated on a prototype of /spl gamma/-ray detector employing a GSO crystal of similar cross-section. This detector presents a minimum energy threshold of about 50 keV at room temperature (20/spl deg/C) or 25 keV at 0/spl deg/C. The measured energy resolution at room temperature is 22.65% and 8.73% FWHM at 122 keV and 662 keV respectively. These performances were obtained by using a shaping time of 0.5 /spl mu/s which allows to operate at high /spl gamma/-ray interaction rate. The effect of the SDC drift-time on the detector gain has been also evaluated.

First experimental results of a new gamma-ray detector based on a Silicon Drift Chamber coupled to a Scintillator

A γ-ray detector consisting in a CsI(Tl) scintillator coupled to a Silicon Drift Chamber (SDC), has been realized and tested. Experimental results, obtained with a prototype based on a scintillator of 3mm diameter and 5mm thickness and on a SDC of the same diameter with on-chip electronics, are reported here. The peculiar noise characteristics of the SDC allow this γ-ray detector to operate on a wide energy range with high resolution. An energy threshold of about 10keV at room temperature and of few keV at 0°C has been measured. At 662keV the detector shows an energy resolution of 4.34% FWHM at room temperature, to our knowledge the best result ever obtained with a scintillator.

Construction of the CLEOIII tracking system: Silicon vertex detector and drift chamber

The CLEO III group is constructing a tracking system (4-layer silicon vertex detector and 47-layer central drift chamber) to be compatible with the interaction region to be installed as part of the staged luminosity upgrade program at the Cornell Electron Storage Ring. Compared to CLEO II, the double-sided silicon detector will have improved signal-to-noise due to long integration times and improvements in the p-type implant barrier on the n-type side. Diamond beams will provide a low mass rigid support system. Although having less radial extent than the current CLEO II tracking system, CLEO III will have equivalent momentum resolution because of material reduction in the drift chamber inner wall and gas. Helium based gas provides further improvements in the spatial resolution.

Results of R&D for the proposed intermediate fiber tracker for CDF

A fine granularity scintillating fiber tracking system was proposed for the inetermediate radial range of CDF between silicon vertex detector and central drift chamber. Detailed study of the expected performance especially under high radiation dose showed that the system is highly efficient for the intergrated luminosity of 2 fb −1 to be accumulated in Run II, the run after the Main Injector is completed. Rate capability study was conducted on SSPM and it was found that the high efficiency is well maintained up to several MHz that is expected in Run II.

Scintillation detection using a silicon drift chamber with on-chip electronics

The performances of a Silicon Drift Chamber (SDC), having a diameter of 3 mm, as scintillation light photodetector have been experimentally evaluated on a prototype of hard X-ray spectrometer employing a Csl(Tl) crystal of the same diameter and 5 mm thick. The SDC, with on-chip electronics, is characterized by an electronics noise considerably lower than that exhibited by a conventional photodiode of equal area and thickness. Consequently, the present hard X-ray detector may operate on a wide energy range, with a minimum energy threshold of about 10 keV at room temperature or lower than 5 keV below 10°C. The measured energy resolution at room temperature is 7.49% FWHM at 122 keV and 4.34% FWHM at 662 keV. The same SDC photodetector has been also used together with a Csl(Tl) crystal having a thickness of 10 mm and, consequently, a useful energy range extending up to soft γ-ray energies. While at room temperature the energy resolutions of the two detector configurations are substantially identical, below 10°C the configuration using the smaller crystal shows appreciably better performances.

Gamma ray spectroscopy with CsI(Tl) scintillator coupled to silicon drift chamber

A /spl gamma/-ray detector, designed around a silicon drift chamber having a diameter of 3 mm and coupled to a CsI(Tl) scintillator of the same diameter and 10 mm thick, has been realized and extensively tested. This detector may operate over a wide energy band with a minimum energy threshold that may be set around 10 keV at room temperature or at around 4 keV at 0/spl deg/C. At the typical energy of 662 keV used to characterize a /spl gamma/-ray spectrometer, an energy resolution of 4.4% full-width at half-maximum has been measured at room temperature. This detector shows high energy resolution over the full energy range explored, 6 keV-1.27 MeV, and to our knowledge the results reported are the best ever obtained with a scintillator.

Conceptual development of a new ultraviolet detector

The concept of a new bidimensional photon-counting, MCPbased detector is presented together with estimates of imaging and dynamic range performances. The first results of tests on the position readout system, a silicon drift chamber, are also presented.

Simulation and modelling of a new silicon X-ray drift detector design for synchrotron radiation applications

In this paper we describe the design of a new type of detector based on silicon drift chamber (SDC) detectors for near-room temperature X-ray absorption fine structure (EXAFS) applications. Theoretical analysis shows that these devices are capable of electronic noise levels that are competitive with cryogenic detectors at significantly higher count rates. Novel field-plate electrodes and integration of the FET with the use of a secondary epitaxial layer will be discussed. Results of modelling and simulation of the new SDC structures will be presented.

A study of the silicon drift chamber

A proto-type silicon drift chamber has been tested mainly by using an LED. The characteristic behavior of the detector is discussed through the measurement of electron drift time. Under a special situation the anode signal showed the increasing rise time and the decreasing amplitude with the drift distance. The former is understood at least by the electro-static repulsion of the electron cloud, while the latter is suggestive of the trapping of electron to some impurity levels.

Designing a linear silicon drift detector

The design and 2D simulation results of a Silicon Drift Chamber with a rectangular configuration are presented. The proposed structure is intended to allow a test of the technology used in the production of the device and serve as a basis to verify different solutions in the design of drift detectors. >