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PAN is a scientific instrument suitable for deep space and interplanetary missions. It can precisely measure and monitor the flux, composition, and direction of highly penetrating particles ( >∼ 100 MeV/nucleon) in deep space, over at least one full solar cycle (11 years). The science program of PAN is multi- and cross-disciplinary, covering cosmic ray physics, solar physics, space weather and space travel. PAN will fill an observation gap of galactic cosmic rays in the GeV region, and provide precise information of the spectrum, composition and emission time of energetic particle originated from the Sun. The precise measurement and monitoring of the energetic particles is also a unique contribution to space weather studies. PAN will map the flux and composition of penetrating particles, which cannot be shielded effectively, precisely and continuously, providing valuable input for the assessment of the related health risk, and for the development of an adequate mitigation strategy. PAN has the potential to become a standard on-board instrument for deep space human travel. PAN is based on the proven detection principle of a magnetic spectrometer, but with novel layout and detection concept. It will adopt advanced particle detection technologies and industrial processes optimized for deep space application. The device will require limited mass (20 kg) and power (20 W) budget. Dipole magnet sectors built from high field permanent magnet Halbach arrays, instrumented in a modular fashion with high resolution silicon strip detectors, allow to reach an energy resolution better than 10% for nuclei from H to Fe at 1 GeV/n. The charge of the particle, from 1 (proton) to 26 (Iron), can be determined by scintillating detectors and silicon strip detectors, with readout ASICs of large dynamic range. Silicon pixel detectors used in a low power setting will maintain the detection capabilities for even the strongest solar events. A fast scintillator with silicon photomultiplier (SiPM) readout will provide timing information to determine the entering direction of the particle, as well as a high rate particle counter. Low noise, low power and high density ASIC will be developed to satisfy the stringent requirement of the position resolution and the power consumption of the tracker. PAN is a scientific instrument suitable for deep space and interplanetary missions. It can precisely measure and monitor the flux, composition, and direction of highly penetrating particles ($> \sim$100 MeV/nucleon) in deep space, over at least one full solar cycle (~11 years). The science program of PAN is multi- and cross-disciplinary, covering cosmic ray physics, solar physics, space weather and space travel. PAN will fill an observation gap of galactic cosmic rays in the GeV region, and provide precise information of the spectrum, composition and emission time of energetic particle originated from the Sun. The precise measurement and monitoring of the energetic particles is also a unique contribution to space weather studies. PAN will map the flux and composition of penetrating particles, which cannot be shielded effectively, precisely and continuously, providing valuable input for the assessment of the related health risk, and for the development of an adequate mitigation strategy. PAN has the potential to become a standard on-board instrument for deep space human travel. PAN is based on the proven detection principle of a magnetic spectrometer, but with novel layout and detection concept. It will adopt advanced particle detection technologies and industrial processes optimized for deep space application. The device will require limited mass (~20 kg) and power (~20 W) budget. Dipole magnet sectors built from high field permanent magnet Halbach arrays, instrumented in a modular fashion with high resolution silicon strip detectors, allow to reach an energy resolution better than 10\% for nuclei from H to Fe at 1 GeV/n.

The IDEAS IDE3380 mixed-signal SiPM readout ASIC and ADC technology for space in AMS 0.35μm CMOS shows no relevant change below 340 krad(Si) TID, no latch-up below 137 MeV cm2/mg, and no SEU/SETs below 18 MeV cm2/mg.

Archaologische Funde aus der Romischen Kaiserzeit belegen, dass man bereits in den ersten nachchristlichen Jahrhunderten immer wieder nach Losungen fur die Wasserversorgungsprobleme in den Marschengebieten der Nordseekuste suchte. Die Bewaltigung dieser Problematik bestand aus einfachen Anlagen in Form von naturlichen Wasserkuhlen bis hin zu komplizierten Konstruktionen wie Schachtbrunnen aus Holz mit Sodentrichter, Flechtwandkorben und Ablaufgraben. Besonders aufwandig war die Wasserversorgung mit Fething und Sod auf den nordfriesischen Halligen. Erst die Flutkatastrophe von 1962 verursachte einen radikalen Wandel. Da durch den Orkan Salzwasser in die historischen Versorgungsanlagen eingedrungen war, konnten diese nicht mehr fur die Trinkwasserzwecke genutzt werden und wurden durch Trinkwasserleitungen vom Festland ersetzt. Lediglich die Wasserkuhlen und einige Fethinge haben die Zeit uberdauert und haben eine Aussicht auf zukunftige Nutzung.

SIPHRA is a low-power (30 mW) application specific integrated circuit (ASIC) recently developed by IDEAS, Norway for readout of photomultiplier tubes (PMTs) and silicon photomultipliers (SiPMs). The ASIC has 16 input channels and one summing channel. Each channel can be used for timing and pulse height spectroscopy with a programmable shaping time of 200 ns, 400 ns, 800 ns, or 1600 ns. The current mode input stage (CMIS) is designed for large negative charge (-16 nC, -8 nC, -4 nC, and 0.4 nC), depending on the programmable attenuation. The ASIC contains a 12-bit ADC for pulse-height digitization. SIPHRA’s performance has been tested using a 4 $\times$4 array of 6 mm Jseries SiPMs from SensL and a number of scintillator crystals (BGO, LYSO, $LaBr_{3}:Ce and CeBr_{3}$). The $LaBr_{3}$:Ce detector has shown energy resolution (FWHM) of 3.4% at 662 keV and 2.5% at 1274 keV. In further measurements with a light emitting diode, the SiPMs have demonstrated the same energy resolution as obtained using discrete readout electronics.

A demonstrator of the portable position sensitive neutron detecting device for neutron imaging in a mixed radiation field is presented. A detector of the device is based on multilayer perpendicularly crossed strip sensors interlaced with neutron converter. A 6LiF converter producing energetic alpha particles and tritons is used. The converter permits precise determination of a position of the neutron interaction even in a radiation fields with a high gamma background. The neutron detection efficiency is increased with a 3D structured surface of the multilayer silicon strip sensor. The demonstrator is comprised of the neutron sensitive multilayer silicon strip detector, a 128 channel general purpose charge sensitive amplifier ASICs IDEAS VATAGP8 with nominal dynamic range of +/− 250 fC, a 13 bit analogue to digital conversion and an FPGA control. Basic characteristics of the amplifier like amplifier linearity probed with an external charge generator is shown. Moreover, results of experimental tests of the demonstrator with alpha, beta, gamma sources and neutrons is demonstrated. The device may be used for neutron imaging via position sensitive detection of particular neutrons on the basis of coincidence detection of neutron conversion products or on the basis of response comparison of individual strips. An effect of charge sharing between individual strips on position resolution will be elaborately discussed.

The detector readout for the Radiation-hard Electron Monitor (RADEM) aboard the JUpiter ICy moons Explorer (JUICE) uses a custom-made application-specific integrated circuit (ASIC, model: IDE3466) for the charge signal readout from silicon radiation sensors. RADEM measures the total ionizing dose and dose rate for protons (5 MeV to 250 MeV), electrons (0.3 MeV to 40 MeV) and ions. RADEM has in total three chips of the same design: one chip for the proton and ion detector, one for the electron detector, and one for the directional detector. The ASIC has 36 chargesensitive pre-amplifiers (CSA), 36 counters of 22-bits each, and one analogue output for multiplexing the pulse heights from all channels. The counters count pulses from charged particles in the silicon sensors depending on the charge magnitude and the coincidence trigger pattern from the 36 channels. We have designed the ASIC in 0.35-μm CMOS process and an ASIC wafer lot has been manufactured at AMS. This article presents the ASIC design specifications and design validation results. The preliminary results from tests with bare chips indicate that the design meets the technical requirements.

This work is a continuation of our preliminary tests on NIRCA - the Near Infrared Readout and Controller ASIC [1]. The primary application for NIRCA is future astronomical science and Earth observation missions where NIRCA will be used with mercury cadmium telluride image sensors (HgCdTe, or MCT) [2], [3]. Recently we have completed the ASIC tests in the cryogenic environment down to 77 K. We have verified that NIRCA provides to the readout integrated circuit (ROIC) regulated power, bias voltages, and fully programmable digital sequences with sample control of the analogue to digital converters (ADC). Both analog and digital output from the ROIC can be acquired and image data is 8b/10bencoded and delivered via serial interface. The NIRCA also provides temperature measurement, and monitors several analog and digital input channels. The preliminary work confirms that NIRCA is latch-up immune and able to operate down to 77 K. We have tested the performance of the 12-bit ADC with pre-amplifier to have 10.8 equivalent number of bits (ENOB) at 1.4 Msps and maximum sampling speed at 2 Msps. The 1.8-V and 3.3-V output regulators and the 10-bit DACs show good linearity and work as expected. A programmable sequencer is implemented as a micro-controller with a custom instruction set. Here we describe the special operations of the sequencer with regards to the applications and a novel approach to parallel real-time hardware outputs. The test results of the working prototype ASIC show good functionality and performance from room temperature down to 77 K. The versatility of the chip makes the architecture a possible candidate for other research areas, defense or industrial applications that require analog and digital acquisition, voltage regulation, and digital signal generation.

We describe an MR-compatible SPECT camera for small animals. The SPECT camera system can be inserted into the bore of a state-of-the-art MRI system and allows researchers to acquire tomographic images from a mouse in-vivo with the MRI and the SPECT acquiring simultaneously. The SPECT system provides functional information, while MRI provides anatomical information. Until today it was impossible to operate conventional SPECT inside the MRI because of mutual interference. The new SPECT technology is based on semiconductor radiation sensors (CZT, ASICs), and it fits into conventional high field MRI systems with a minimum 12-cm bore size. The SPECT camera has an MR-compatible multi-pinhole collimator for mice with a O25-mm field-of-view. For the work reported here we assembled a prototype SPECT camera system and acquired SPECT and MRI data from radioactive sources and resolution phantoms using the camera outside and inside the MRI.

The goal of this paper was to investigate the benefits that could be realistically achieved on a microCT imaging system with an energy-resolved photon-counting x-ray detector. To this end, we built and evaluated a prototype microCT system based on such a detector. The detector is based on cadmium telluride (CdTe) radiation sensors and application-specific integrated circuit (ASIC) readouts. Each detector pixel can simultaneously count x-ray photons above six energy thresholds, providing the capability for energy-selective x-ray imaging. We tested the spectroscopic performance of the system using polychromatic x-ray radiation and various filtering materials with K-absorption edges. Tomographic images were then acquired of a cylindrical PMMA phantom containing holes filled with various materials. Results were also compared with those acquired using an intensity-integrating x-ray detector and single-energy (i.e. non-energy-selective) CT. This paper describes the functionality and performance of the system, and presents preliminary spectroscopic and tomographic results. The spectroscopic experiments showed that the energy-resolved photon-counting detector was capable of measuring energy spectra from polychromatic sources like a standard x-ray tube, and resolving absorption edges present in the energy range used for imaging. However, the spectral quality was degraded by spectral distortions resulting from degrading factors, including finite energy resolution and charge sharing. We developed a simple charge-sharing model to reproduce these distortions. The tomographic experiments showed that the availability of multiple energy thresholds in the photon-counting detector allowed us to simultaneously measure target-to-background contrasts in different energy ranges. Compared with single-energy CT with an integrating detector, this feature was especially useful to improve differentiation of materials with different attenuation coefficient energy dependences.

Purpose: The objective of the study was to demonstrate that, in x-ray computed tomography (CT), more than two types of materials can be effectively separated with the use of an energy resolved photon-counting detector and classification methodology. Specifically, this applies to the case when contrast agents that contain K-absorption edges in the energy range of interest are present in the object. This separation is enabled via the use of recently developed energy resolved photon-counting detectors with multiple thresholds, which allow simultaneous measurements of the x-ray attenuation at multiple energies. Methods: To demonstrate this capability, we performed simulations and physical experiments using a six-threshold energy resolved photon-counting detector. We imaged mouse-sized cylindrical phantoms filled with several soft-tissue-like and bone-like materials and with iodine-based and gadolinium-based contrast agents. The linear attenuation coefficients were reconstructed for each material in each energy window and were visualized as scatter plots between pairs of energy windows. For comparison, a dual-kVp CT was also simulated using the same phantom materials. In this case, the linear attenuation coefficients at the lower kVp were plotted against those at the higher kVp. Results: In both the simulations and the physical experiments, the contrast agents were easily separable from other soft-tissue-like and bone-like materials, thanks to the availability of the attenuation coefficient measurements at more than two energies provided by the energy resolved photon-counting detector. In the simulations, the amount of separation was observed to be proportional to the concentration of the contrast agents; however, this was not observed in the physical experiments due to limitations of the real detector system. We used the angle between pairs of attenuation coefficient vectors in either the 5-D space (for non-contrast-agent materials using energy resolved photon-counting acquisition) or a 2-D space (for contrast agents using energy resolved photon-counting acquisition and all materials using dual-kVp acquisition) as a measure of the degree of separation. Compared to dual-kVp techniques, an energy resolved detector provided a larger separation and the ability to separate different target materials using measurements acquired in different energy window pairs with a single x-ray exposure. Conclusions: We concluded that x-ray CT with an energy resolved photon-counting detector with more than two energy windows allows the separation of more than two types of materials, e.g., soft-tissue-like, bone-like, and one or more materials with K-edges in the energy range of interest. Separating material types using energy resolved photon-counting detectors has a number of advantages over dual-kVp CT in terms of the degree of separation and the number of materials that can be separated simultaneously.

Single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high-spatial resolution anatomical information as well as complementary functional information. In this study, we utilized a dual modality SPECT/MRI (MRSPECT) system to investigate the integration of SPECT and MRI for improved image accuracy. The MRSPECT system consisted of a cadmiumzinc-telluride (CZT) nuclear radiation detector interfaced with a specialized radiofrequency (RF) coil that was placed within a whole-body 4 T MRI system. The importance of proper corrections for non-uniform detector sensitivity and Lorentz force effects was demonstrated. MRI data were utilized for attenuation correction (AC) of the nuclear projection data and optimized Wiener filtering of the SPECT reconstruction for improved image accuracy. Finally, simultaneous dual-imaging of a nude mouse was performed to demonstrated the utility of co-registration for accurate localization of a radioactive source.

In this paper we present initial test results of the Near Infrared Readout and Controller ASIC (NIRCA), designed for large area image sensors under contract from the European Space Agency (ESA) and the Norwegian Space Center. The ASIC is designed to read out image sensors based on mercury cadmium telluride (HgCdTe, or MCT) operating down to 77 K. IDEAS has developed, designed and initiated testing of NIRCA with promising results, showing complete functionality of all ASIC sub-components. The ASIC generates programmable digital signals to clock out the contents of an image array and to amplify, digitize and transfer the resulting pixel charge. The digital signals can be programmed into the ASIC during run-time and allows for windowing and custom readout schemes. The clocked out voltages are amplified by programmable gain amplifiers and digitized by 12-bit, 3-Msps successive approximation register (SAR) analogue-to-digital converters (ADC). Digitized data is encoded using 8-bit to 10-bit encoding and transferred over LVDS to the readout system. The ASIC will give European researchers access to high spectral sensitivity, very low noise and radiation hardened readout electronics for astronomy and Earth observation missions operating at 77 K and room temperature. The versatility of the chip makes the architecture a possible candidate for other research areas, or defense or industrial applications that require analog and digital acquisition, voltage regulation, and digital signal generation.

Reconstruction of coastal development, environment and settlement history is one of the main objectives of coastal archaeology in Schleswig–Holstein. The fieldwork program concentrated until 1975 on the excavation of dwelling mounds, and after that on the reconstruction of the landscape and settlement history of large areas. Cultural elements of the coastal area were mapped in several surveys integrating archaeological, geological and palaeobotanical aspects on the island of Sylt (Archsum project), in the North Frisian tidal flats (Norderhever project), on the Eiderstedt penisula, and in Dithmarschen. According to this kind of research, environmental changes dominated the settlement history and settlement pattern in the 1st millennium AD. Archaeological finds and excavations indicate that the earliest coastal settlements were founded in the salt marshes of Schleswig–Holstein in the early Roman period. In Dithmarschen as well as in the southern part of Eiderstedt the river marshes and salt marshes were densely populated during this period. In the 1st and 2nd century AD the inhabitation of the area took place in a phase of lowering of the sea level. The settlements were erected on the natural surface of the coastal marshland, preferably on elevated areas. Thereafter, a rising sea level and intensified flooding led to the abandonment of some settlements. At other localities the inhabitants protected themselves against the storm surges by the construction of dwelling mounds, so-called Wurten . The first phase of inhabitation of the coastal marshland ended at about AD 450. A second phase of inhabitation of the coastal marshes began in the middle or late 7th century AD. It started with new settlements on the natural land surface of the marshland and was followed by as second phase of Wurt construction. The present-day North Frisian tidal flat area was covered with extended peat bogs and could not be inhabited before high Medieval times. Starting with this period the natural landscape changed to a cultural landscape. Cooperatives of peasants and the parishes played an important role in this process. Dikes were built and deep seated areas were drained and cultivated. In the late Middle Ages catastrophic storm floods had terrible effects: the sea destroyed large parts of the North Frisian Utlande. Remnants of this period like Warften , dikes, field pattern, and churches, are still visible in the present-day tidal flats. The unfavourable combination of human activities (peat cutting for salt production) and natural geological processes was responsible for the catastrophic floods of late Medieval times. Cultural monuments of this evolution are still preserved in the coastal landscape. The protection of the Cultural Heritage is of high value for the future.

Chemical Vapor Deposited (CVD) polycrystalline diamond has been proposed as a radiation-hard alternative to silicon in the extreme radiation levels occurring close to the interaction region of the Large Hadron Collider. Due to an intense research effort, reliable high-quality polycrystalline CVD diamond detectors, with up to 270 μm charge collection distance and good spatial uniformity, are now available. The most recent progress on the diamond quality, on the development of diamond trackers and on radiation hardness studies are presented and discussed.

Applications in nuclear medicine and bio-medical engineering may profit using a Compton camera for imaging distributions of radio-isotope labelled tracers in organs and tissues. These applications require detection of photons using thick position-sensitive silicon sensors with the highest possible energy and good spatial resolution. In this paper, research and development on silicon pad sensors and associated readout electronics for a Compton camera are presented. First results with low-noise, self-triggering VATAGP ASIC's are reported. The measured energy resolution was 1.1 keV FWHM at room temperature for the 241 Am photo-peak at 59.5 keV .

The article describes the near infrared readout and controller ASIC (NIRCA) developed by Integrated Detector Electronics AS (IDEAS). The project aims at future astronomical science and Earth observation missions, where the ASIC will be used with image sensors based on mercury cadmium telluride (HgCdTe, or MCT). NIRCA is designed to operate from cryogenic temperatures (77 K) to higher than room temperature (328 K) and in a high radiation environment (LET > 60 MeVcm2/mg). The ASIC connects to the readout integrated circuit (ROIC) and delivers fully digitized data via serial digital output. The ASIC contains an analogue front-end (AFE) with 4 analogue-to-digital converters (ADCs) and programmable gain amplifiers with offset adjustment. The ADCs have a differential input swing of ±2 V, 12-bit resolution, and a maximum sample rate of 3 MSps. The ASIC contains a programmable sequencer (microcontroller) to generate up to 40 digital signals for the ROIC and to control the analogue front-end and DACs on the chip. The ASIC has two power supply voltage regulators that provide the ROIC with 1.8 V and 3.3 V, and programmable 10-bit DACs to generate 16 independent reference and bias voltages from 0.3 V to 3 V. In addition NIRCA allows one to read 8 external digital signals, and monitor external and internal analogue signals including onchip temperature. NIRCA can be programmed and controlled via SPI interface for all internal functions and allows data forwarding from and to the ROIC SPI interface.

Single photon emission tomography (SPET or SPECT) and magnetic resonance imaging (MRI) are in use routinely in hospitals worldwide. Each of these modalities is steadily growing in study volume and makes a major contribution to healthcare, with approximately 40 million SPECT and 60 million MRI patient exams completed every year. Also in the preclinical research field both SPECT and MRI are found to play important roles, with an installed base of about 200 microSPECT and 400 small animal MRI systems in use as of the beginning of 2009. The high magnetic field strengths of modern MRI machines, both clinical and preclinical, preclude the use of conventional photomultiplier-tube based SPECT equipment in the vicinity of the magnet. If a patient or a laboratory animal is to be imaged by both modalities, the two studies must be done in separate imaging sessions—always in different rooms and often in different departments and sometimes even in different buildings within a medical facility. Combined SPECT/MRI imaging is important since non-invasive probing of intact, living biological organisms—human or laboratory animal—bridges the gap between exponentially growing understanding of molecular and genetic mechanisms and the phenotypical embodiments of diseases and their response to treatments.

CVD diamond material was used to build position-sensitive detectors for single-charged particles to be employed in high-intensity physics experiments. To obtain position information, metal contacts shaped as strips or pixels are applied to the detector surface for one- or two-dimensional coordinate measurement. Strip detectors 2×4 cm2 in size with a strip distance of 50 μm were tested. Pixel detectors of various pixel sizes were bump bonded to electronics chips and investigated. A key issue for the use of these sensors in high intensity experiments is the radiation hardness. Several irradiation experiments were carried out with pions, protons and neutrons exceeding a fluence of 1015 particles/cm2. The paper presents an overview of the results obtained with strip and pixel detectors in high-energy test beams and summarises the irradiation studies.

Diamond based pixel detectors are a promising radiation-hard technology for use at the LHC. We present first results on a CMS diamond pixel sensor. With a threshold setting of 2000 electrons, an average pixel efficiency of 78% was obtained for normally incident minimum ionizing particles.

In this article we present the performance of recent chemical vapour deposition (CVD) diamond micro-strip sensors in beam tests. In addition, we present the first comparison of a CVD diamond micro-strip sensor before and after proton irradiation.

Recent progress on developing diamond-based sensors for vertex detection at high luminosity hadron colliders is described. Measurements of the performance of diamond sensors after irradiation to fluences of up to 5/spl times/10/sup 15/ hadrons/cm/sup 2/ are shown. These indicate that diamond sensors will operate at distances as close as 5 cm from the interaction point at the Large Hadron Collider (LHC) for many years at full luminosity without significant degradation in performance. Measurements of the quality of the signals from diamond sensors as well as spatial uniformity are presented. Test beam results on measurements of diamond-based microstrip and pixels devices are described.

The paper reviews measurements of the radiation hardness of CVD diamond for 24 GeV/c proton irradiation at fluences up to 5 ∗ 10 15 protons/cm 2 . The results not only show radiation damage but also an annealing effect that is dominant at levels around 10 15 protons/cm 2 . A model describing both effects is introduced, enabling a prediction of the distribution curve of the charge signal for other levels.

In future HEP accelerators, such as the LHC (CERN), detectors and electronics in the vertex region of the experiments will suffer from extreme radiation. Thus radiation hardness is required for both detectors and electronics to survive in this harsh environment. CVD diamond, which is investigated by the RD42 Collaboration at CERN, can meet these requirements. Samples of up to 2×4 cm 2 have been grown and refined for better charge collection properties, which are measured with a β source or in a testbeam. A large number of diamond samples has been irradiated with hadrons to fluences of up to 5×10 15 cm −2 to study the effects of radiation. Both strip and pixel detectors were prepared in various geometries. Samples with strip metallization have been tested with both slow and fast readout electronics, and the first diamond pixel detector proved fully functional with LHC electronics.

CVD diamond radiation sensors are being developed for possible use in trackers in the LHC experiments. The diamond promises to be radiation hard well beyond particle fluences that can be tolerated by Si sensors. Recent results from the RD 42 collaboration on charge collection distance and on radiation hardness of CVD diamond samples will be reported. Measurements with diamond tracking devices, both strip detectors and pixel detectors, will be discussed. Results from beam tests using a diamond strip detector which was read out with fast, 25 ns shaping time, radiation-hard pipeline electronics will be presented.

A mathematical model has been developed for the extraction of oligomers from granular polymers with solvent. The model accounts for effective diffusion of the oligomer in the polymer pearls, axial dispersion of the pellets and liquid phase and distribution equilibrium at the interface. The results of numerical simulations of the model are consistent with experimental data. The influence of the physico-chemical parameters on the oligomer concentration in the pellets is shown in terms of a sensitivity analysis. The model can be used for analysis and design calculation of extraction of oligomers either in batch or continuous processes.

Diamond may make an excellent substrate for a tracking device in the near future, especially at colliders like LHC, where extreme running conditions are expected (high rates and high radiation levels). We report on neutron irradiation of several CVD-diamond samples at the ISIS facility (Rutherford Appleton Laboratory), which provides a fast neutron spectrum similar to that expected in a high luminosity collider experiment like CMS. We measured beam-induced currents and charge collection of diamonds exposed to fluences in excess of 10 15 n/cm 2 (peaking at 1 MeV), which should be the maximum value of the ten years total fluence at the design LHC luminosity. Physical hypotheses for the interactions of neutrons on CVD-diamond are proposed.

Polymers may contain low molecular organic components due to incomplete conversion, contaminated raw materials and/or undesirable side reactions. Aqueous polymer solutions, e.g. dispersion paints, adhesives or refining media in the paper industry, are usually applied to large surfaces. During this operation, low molecular weight components are emitted into the ambient air if not removed before. While existing removal processes operate fairly well, the mass transfer steps are still poorly understood and therefore there are no designing data which can be claimed to be reliable. Here a mechanistical mathematical model is presented which accounts for the crucial mass transfer steps occurring in a stationary continuous, well mixed stripping apparatus. Phase equilibria and attainable monomer removal have been determined experimentally in an aerosol jet loop reactor. The results indicate that an efficient stripping process essentially depends on distribution coefficients, hydrodynamic properties and operating conditions while diffusion inside the latices is negligible. This is true for operating temperatures higher than the polymer glass temperature. These results are in contradiction to statements of some other authors who consider diffusion inside the latex particle as the limiting step.

The IDE 4281 is an application specific integrated circuit (ASIC) that has been designed for the readout of CdTe/CZT radiation detectors in space. The chip can be used for single photon spectroscopy of x-rays and γ -rays with energy between 3.5 keV and 140 keV and rate up to 100 kcps per chip. The chip contains 12 low-noise pre-amplifiers (110 e equivalent noise charge, ENC), each followed by a pulse shaper (6 programmable peaking times from 0.75 µs to 4 µs) and a level comparator for triggering. The amplifiers are optimized for negative polarity input charge up to −5 fC. When a charge from the detector exceeds one of the adjustable thresholds, the chip delivers a data packet containing the address of the triggering channel and it delivers an analog signal proportional to the energy deposited by the photon in the detector. The chip requires positive and negative voltage supplies (+1.5 V and −2 V) and one reference bias current to generate its internal bias currents. The total power is 19 mW in idle state and 25 mW maximum. The chip has a 113-bit shift register, programmable via a serial interface, which allows one to set various functions, to program digital-to-analogue converters (DACs), and to tune parameters. Each channel has an optional compensation for detector leakage currents. All amplifier inputs are protected by diodes against over-voltage and electrostatic discharge (ESD). The engineering model (EM) and flight model (FM) ASICs have been designed and manufactured. The article describes the results obtained with the EM ASIC and the design of the FM ASIC.

The ESA Next Generation Radiation Monitor (NGRM) will be the successor of the ESA Standard Radiation Environment Monitor (SREM) that is still measuring near-Earth and interplanetary space radiation environment onboard 6 different spacecrafts. NGRM will measure protons from 2 MeV up to 200 MeV, electrons from 100keV up to 7MeV, as well as LET spectrum of ions. Compared to SREM, NGRM will provide a much better energy resolution, will be smaller (

The IDE 3465 is an application specific integrated circuit (ASIC) that has been designed for the readout of silicon detectors for charged particles. The chip has 20 inputs of charge sensitive pre-amplifiers (CSA), a total of 37 digital logic trigger outputs, and one analogue multiplexer output for pulse heights. Out of the 20 channels, 16 have a high gain with saturation at 2.6 pC, and 4 have a low gain with saturation at 26 pC. The chip is optimized for positive input charges, i.e., it is suitable for the readout and triggering of the charge from the p-side of silicon sensors. In the high-gain channels, the charge sensitive pre-amplifier is connected to one slow shaper of 1-µs shaping time and two fast shapers of 250-ns shaping time, while the low-gain channels have only one slow shaper and one fast shaper of 1-µs and 250-ns shaping time. Each fast shaper output is connected to a comparator, which triggers when the pulse shape exceeds the reference level that can be programmed by 8-bit DACs. The two fast shapers and comparators of the high-gain channels are used for charges in the range from 1 fC to 100 fC and from 100 fC to 2.6 pC, respectively. The fast shapers and comparators of the low-gain channels are designed for charges in the range from 1 pC to 26 pC. Each comparator feeds a mono-stable output, which can be connected directly to an FPGA. The chip requires negative and positive voltage supplies (−2 V, +1.5 V and +3.3 V) and one reference bias current to generate its internal biases. The total power consumption is less than 65 mW, depending on the input event rate and options enabled. The chip has a 356-bit register, programmable via serial interface, which allows one to set various functions, to program digital-to-analogue converters (DACs), and to tune parameters. All amplifier inputs are protected by diodes against over-voltage and electro-static discharge (ESD). The chip is SEU/SEL radiation hardened by design and manufacture.

The ESA Next Generation Radiation Monitor (NGRM), actually under development, will be the successor of the ESA Standard Radiation Environment Monitor (SREM) that is still measuring near-Earth and interplanetary space radiation environment onboard 6 different spacecrafts. NGRM will measure protons from 2 MeV up to 200 MeV, efrom 100keV up to 7MeV, as well as LET spectrum of ions. Compared to SREM, NGRM will provide a much better energy resolution, will be smaller (

To analyze the flow patterns of the left blood chamber of the Baylor total artificial heart (TAH) and to evaluate influences of the inflow valve angle to the flow patterns, flow visualization studies were performed. The inflow valve angle of the left housing was changed by 20 degrees orthogonal to the inflow tube, and comparison studies of the modified and unmodified models were made. For evaluating sectional flow patterns, a laser light was used, the clear transparent housing was scanned segmentally, and flow patterns were recorded on high contrast film for measuring flow velocities. A signal was used that synchronized the timing of the camera shutter to the pusher-plate movement signal. With the modified 20 degree inflow valve direction, there were better closing characteristics of the inflow valve leaflets. At the same time, we could successfully reduce the vortex formation at the inflow port, which may cause thrombus formation. We also have improved the washout during the diastolic phase in not only the bottom area, but in the entire pumping chamber. This flow visualization setup is simple and inexpensive. It is useful not only for validation of global flow patterns, but also for validation of local flow velocities of various blood pumps.

Despite its high sensitivity, the variable specificity of magnetic resonance imaging (MRI) in breast cancer diagnosis can lead to unnecessary biopsies and over-treatment. Scintimammography (SMM) could potentially supplement MRI for improving the diagnostic specificity. The synergistic combination of MRI and SMM (MRSMM) could result in both high sensitivity from MRI and high specificity from SMM. Development of such a dual-modality system requires the integration of a radio frequency (RF) coil and radiation detector in a strong magnetic field without significant mutual interference. In this study, we developed and tested a unilateral breast array coil specialized for MRSMM imaging. The electromagnetic (EM) field, specific absorption ratio (SAR), and RF coil parameters with cadmium-zinc-telluride (CZT) detectors encapsulated in specialized RF and gamma-ray shielding mounted within the RF coil were investigated through simulation and experimental measurements. Simultaneous MR and SMM images of a breast phantom were also acquired using the integrated MRSMM system. This work, we feel, represents an important step toward the fabrication for a working MRSMM system.

We describe a method of interpolation for a pixellated γ-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.

Radiolabeled cells have been imaged for decades in the field of autoradiography. Recent advances in detector and microelectronics technologies have enabled the new field of "digital autoradiography" which remains limited to ex vivo specimens of thin tissue slices. The 3D field-of-view (FOV) of single cell imaging can be extended to millimeters if the low energy (10-30 keV) photon emissions of radionuclides are used for single-photon nuclear imaging. This new microscope uses a coded aperture foil made of highly attenuating elements such as gold or platinum to form the image as a kind of "lens". The detectors used for single-photon emission microscopy are typically silicon detectors with a pixel pitch less than 60 μm. The goal of this work is to image radiolabeled mesenchymal stem cells in vivo in an animal model of tendon repair processes. Single-photon nuclear imaging is an attractive modality for translational medicine since the labeled cells can be imaged simultaneously with the reparative processes by using the dual-isotope imaging technique. The details our microscope's two-layer gold aperture and the operation of the energy-dispersive, pixellated silicon detector are presented along with the first demonstration of energy discrimination with a 57 Co source. Cell labeling techniques have been augmented by genetic engineering with the sodium-iodide symporter, a type of reporter gene imaging method that enables in vivo uptake of free 99m Tc or an iodine isotope at a time point days or weeks after the insertion of the genetically modified stem cells into the animal model. This microscopy work in animal research may expand to the imaging of reporter-enabled stem cells simultaneously with the expected biological repair process in human clinical trials of stem cell therapies.

The need to understand the behavior of individual stem cells at the various stages of their differentiation and to assess the resulting reparative action in pre-clinical model systems, which typically involves laboratory animals, provides the motivation for imaging of stem cells in vivo at high resolution. Our initial focus is to image cells and cellular events at single cell resolution in vivo in shallow tissues (few mm of intervening tissue) in laboratory mice and rates. In order to accomplish this goal we are building a SPECT-based microscope. We based our design on earlier theoretical work with near-field coded apertures and have adjusted the components of the system to meet the real-world demands of instrument construction and of animal imaging. Our instrumental design possesses a reasonable trade-off between field-of-view, sensitivity, and contrast performance (photon penetration). A layered gold aperture containing 100 pinholes and intended for use in coded aperture imaging application has been designed and constructed. A silicon detector connected to a TimePix readout from the CERN collaborative group was selected for use in our prototype microscope because of its ultra-high spatial and energy resolution capabilities. The combination of the source, aperture, and detector has been modeled and the coded aperture reconstruction of simulated sources is presented in this work.

The objective of the study was to demonstrate that, in x-ray computed tomography (CT), more than two types of materials can be effectively separated with the use of an energy resolved photon-counting detector and classification methodology. Specifically, this applies to the case when contrast agents that contain K-absorption edges in the energy range of interest are present in the object. This separation is enabled via the use of recently developed energy resolved photon-counting detectors with multiple thresholds, which allow simultaneous measurements of the x-ray attenuation at multiple energies.To demonstrate this capability, we performed simulations and physical experiments using a six-threshold energy resolved photon-counting detector. We imaged mouse-sized cylindrical phantoms filled with several soft-tissue-like and bone-like materials and with iodine-based and gadolinium-based contrast agents. The linear attenuation coefficients were reconstructed for each material in each energy window and were visualized as scatter plots between pairs of energy windows. For comparison, a dual-kVp CT was also simulated using the same phantom materials. In this case, the linear attenuation coefficients at the lower kVp were plotted against those at the higher kVp.In both the simulations and the physical experiments, the contrast agents were easily separable from other soft-tissue-like and bone-like materials, thanks to the availability of the attenuation coefficient measurements at more than two energies provided by the energy resolved photon-counting detector. In the simulations, the amount of separation was observed to be proportional to the concentration of the contrast agents; however, this was not observed in the physical experiments due to limitations of the real detector system. We used the angle between pairs of attenuation coefficient vectors in either the 5-D space (for non-contrast-agent materials using energy resolved photon-counting acquisition) or a 2-D space (for contrast agents using energy resolved photon-counting acquisition and all materials using dual-kVp acquisition) as a measure of the degree of separation. Compared to dual-kVp techniques, an energy resolved detector provided a larger separation and the ability to separate different target materials using measurements acquired in different energy window pairs with a single x-ray exposure.We concluded that x-ray CT with an energy resolved photon-counting detector with more than two energy windows allows the separation of more than two types of materials, e.g., soft-tissue-like, bone-like, and one or more materials with K-edges in the energy range of interest. Separating material types using energy resolved photon-counting detectors has a number of advantages over dual-kVp CT in terms of the degree of separation and the number of materials that can be separated simultaneously.

We describe a continuing design and development of MR-compatible SPECT systems for simultaneous SPECT-MR imaging of small animals. A first generation prototype SPECT system was designed and constructed to fit inside a MRI system with a gradient bore inner diameter of 12 cm. It consists of 3 angularly offset rings of 8 detectors (1"x1", 16x16 pixels MR-compatible solid-state CZT). A matching 24-pinhole collimator sleeve, made of a tungsten-compound, provides projections from a common FOV of ~25 mm. A birdcage RF coil for MRI data acquisition surrounds the collimator. The SPECT system was tested inside a clinical 3T MRI system. Minimal interference was observed on the simultaneously acquired SPECT and MR images. We developed a sparse-view image reconstruction method based on accurate modeling of the point response function (PRF) of each of the 24 pinholes to provide artifact-free SPECT images. The stationary SPECT system provides relatively low resolution of 3-5 mm but high geometric efficiency of 0.5- 1.2% for fast dynamic acquisition, demonstrated in a SPECT renal kinetics study using Tc-99m DTPA. Based on these results, a second generation prototype MR-compatible SPECT system with an outer diameter of 20 cm that fits inside a mid-sized preclinical MRI system is being developed. It consists of 5 rings of 19 CZT detectors. The larger ring diameter allows the use of optimized multi-pinhole collimator designs, such as high system resolution up to ~1 mm, high geometric efficiency, or lower system resolution without collimator rotation. The anticipated performance of the new system is supported by simulation data.

In this study, we investigated the in vivo application of an integrated small-animal magnetic resonance (MR) and gamma-ray imaging system that consists of a semiconductor-based radiation detector, a parallel-hole collimator, and a specialized radiofrequency coil. Gadodiamide and (99m)Tc sestimibi agents were injected simultaneously into a mouse, and simultaneous dynamic contrast-enhanced MR and scintigraphic images of the kidneys were acquired. The time curves of both the MR signal intensity and radioactivity indicate a rapid uptake of the agents followed by a more gradual excretion, consistent with the previously reported literature. Our results demonstrate the feasibility of measuring multiple biological processes at the same time using both MR contrast agents and radiotracers.

Conventional x-ray detectors integrate the photon energy flux, losing individual photon energy information. By contrast, energy resolved photon-counting x-ray detectors (PCXDs) count photons in energy windows, thus retaining some energy information. This provides a number of advantages, including the use of energy information to aid in material discrimination. However, this capability relies on accurately measuring changes in the energy spectrum as the x-ray beam passes through the object. Several effects, including characteristic x-ray effects and charge sharing between detector pixels, result in distortions in the energy spectrum that complicate measuring the attenuating effects of the object on the energy spectrum. Our goal was to investigate and develop models for these effects that would be useful in compensating for them in applications involving spectral analysis. We used a previously developed 6-threshold CdTe-based PCXD to validate the models. Previously with this detector we observed higher than predicted counts at low energies. Characteristic x-rays emitted in the detector can distort the spectrum in a pixel via x-ray escape either out of the detector or into adjacent pixels, giving rise to a count with a reduced energy. The escaped x-rays can also produce reduced-energy counts in adjacent pixels. The second effect, charge sharing, results since x-ray interactions in the detector produce a charge cloud with finite size. If close to a pixel boundary and combined with charge diffusion, reduced-energy counts in both pixels can be produced. In this study, we developed a fast Monte Carlo method for modeling characteristic x-ray effects and an analytic method for modeling charge sharing effects. The models produced energy spectra in good agreement with those measured by the PCXD. These models can be used to improve the performance of energy-based composition estimation and ring correction methods by modeling the spectral distortions present in real detectors.

We have developed an application specific integrated circuit (ASIC) suitable for the readout of up to 64 silicon photomultipliers (SiPM) or multi-pixel photon counters (MPPCs). The ASIC can be used with SiPMs/MPPCs and scintillators for energy spectroscopy and timing of ionizing radiation and provides important functionality for SiPMs: The preamplifier input potential can be programmed to adjust the bias voltage for the SiPMs connected to the input. The input charge range is relatively large (−20 pC to 55 pC) and the input noise can be as low as 1 fC. The ASIC triggers, if one of the input signals exceeds the threshold voltage, and the signal amplitude can be sampled. For all readout channels the ASIC delivers the signal amplitude, i.e., photon energy, and the time between the trigger and the sample. The ASIC has a programmable register to configure digital-to-analog converters for the preamplifier input potentials, the trigger thresholds, the internal bias setting and other functionality. Many ASICs can be combined for the readout of multiple arrays of SiPMs/MPPCs. The preamplifier input is designed for capacitive load of up to 300 pF and a dark current of up to 10 μA. We have produced and tested the ASIC connected to MPPCs and LYSO scintillators. The article describes the functionality of the ASIC and shows energy spectra measured with radioactive sources.

The goal of the study was to investigate data acquisition strategies and image reconstruction methods for a stationary SPECT insert that can operate inside an MRI scanner with a 12 cm bore diameter for simultaneous SPECT/MRI imaging of small animals. The SPECT insert consists of 3 octagonal rings of 8 MR-compatible CZT detectors per ring surrounding a multi-pinhole (MPH) collimator sleeve. Each pinhole is constructed to project the field-of-view (FOV) to one CZT detector. All 24 pinholes are focused to a cylindrical FOV of 25 mm in diameter and 34 mm in length. The data acquisition strategies we evaluated were optional collimator rotations to improve tomographic sampling; and the image reconstruction methods were iterative ML-EM with and without compensation for the geometric response function (GRF) of the MPH collimator. For this purpose, we developed an analytic simulator that calculates the system matrix with the GRF models of the MPH collimator. The simulator was used to generate projection data of a digital rod phantom with pinhole aperture sizes of 1 mm and 2 mm and with different collimator rotation patterns. Iterative ML-EM reconstruction with and without GRF compensation were used to reconstruct the projection data from the central ring of 8 detectors only, and from all 24 detectors. Our results indicated that without GRF compensation and at the default design of 24 projection views, the reconstructed images had significant artifacts. Accurate GRF compensation substantially improved the reconstructed image resolution and reduced image artifacts. With accurate GRF compensation, useful reconstructed images can be obtained using 24 projection views only. This last finding potentially enables dynamic SPECT (and/or MRI) studies in small animals, one of many possible application areas of the SPECT/MRI system. Further research efforts are warranted including experimentally measuring the system matrix for improved geometrical accuracy, incorporating the co-registered MRI image in SPECT reconstruction, and exploring potential applications of the simultaneous SPECT/MRI SA system including dynamic SPECT studies.

The overall aim of this work was to evaluate the potential for improving in vivo small animal microCT through the use of an energy resolved photon-counting detector. To this end, we developed and evaluated a prototype microCT system based on a second-generation photon-counting x-ray detector which simultaneously counted photons with energies above six energy thresholds. First, we developed a threshold tuning procedure to reduce the dependence of detector uniformity and to reduce ring artifacts. Next, we evaluated the system in terms of the contrast-to-noise ratio in different energy windows for different target materials. These differences provided the possibility to weight the data acquired in different windows in order to optimize the contrast-to-noise ratio. We also explored the ability of the system to use data from different energy windows to aid in distinguishing various materials. We found that the energy discrimination capability provided the possibility for improved contrast-to-noise ratios and allowed separation of more than two materials, e.g., bone, soft-tissue and one or more contrast materials having K-absorption edges in the energy ranges of interest.