Gradient measurement of the magnetic field vector, especially full-tensor magnetic gradiometers (FTMGs), provides various advantages over gradient components derived from measurements of the total magnetic intensity (TMI). These advantages include higher spatial resolution, directional information, and thus more detailed anomaly delineation and a significantly better-constrained solution space for magnetic inversion and interpretation. However, the airborne application of FTMG instruments requires exceptionally high sensor resolution and low levels of motion noise to maximize these advantages and to achieve high exploration depth. Superconducting quantum interference detectors (SQUIDs) are an effective option for FTMG sensors, now available commercially in the system discussed herein. This SQUID sensor system comprises intrinsic planar-type gradiometers that produce data with sufficiently low noise for use on an airborne platform. The evolution and advancement of the system and its predecessor over the past two decades has produced a robust commercial system that produces high-quality full-tensor data sets from a helicopter-towed-bird implementation. Because the SQUID sensors measure directionally sensitive data, the processing of the acquired data is significantly more challenging than for TMI sensors. Noise induced by the motion of the bird during flight, especially rotational noise, must be monitored and compensated. The introduction of a more robust and aerodynamic bird has significantly reduced the noise of the system. This noise reduction translates into greater sensitivity and accuracy and, thus, heightened confidence in the use of the survey data sets. While much of the early use of the system has been in diamondiferous kimberlite exploration, the system has successfully flown surveys in mineral exploration for a variety of targets, including gold, nickel, and iron ore. These data sets provide greater confidence in the geologic interpretation across the survey areas. Other applications for FTMG surveying include infrastructure mapping, unexploded ordnance detection, and compensation of electromagnetic data sets in marine environments.

Airborne magnetics is one of the most used methods in metalliferous mining geophysics. Full tensor magnetic gradiometer instruments overcome many of the limitations of total field and vector magnetic field sensors, and provide a significant improvement in spatial resolution. The use of new quantum sensors has greatly enhanced the full tensor gradiometry measurement over existing state of the art technologies. The status of the various sensor technologies and SQUID- based instruments is given and one case study is presented.

T-cell activation assays such as Elispot or Intracellular Cytokine Staining (ICS) require appropriate positive stimulation controls. Compared with conventional assay controls based on polyclonal stimulation (e.g. PHA/Ionomycin), peptide pools have the advantage of providing a more physiological, TCR-mediated signal. A frequently used positive control is the so-called ‘CEF’ pool, containing 23 selected class-I-MHC-presented T-cell-stimulating peptides from CMV, EBV, and Influenza A. As a result of frequent and widespread exposure, most if not all individuals have T-cells specific for at least one of these agents. However, the ‘CEF pool’ only covers the most frequent HLA alleles in European-Caucasoids but not other ethnic groups where its usefulness is limited. We, therefore, designed an extended pool referred to as ‘CEFX pool’ with significantly improved coverage of both infectious agents and HLA-alleles (176 peptides), which also contains numerous CD4 T-cell-stimulating peptides. This novel pool provides a much stronger and more universal positive control than the ‘CEF’ pool and was successfully tested in various assay formats including Elispot, ICS, and ELISA of stimulated T-cell supernatants. For specific questions, sub-pools for CD4 or CD8 T-cell stimulation or not containing CMV-derived peptides are available. Because of its broad antigen coverage we are currently exploring the novel pool’s potential for measuring/monitoring general T-cell responsiveness in clinical situations such as immunodeficiency, immunosuppression, or immunosenescence.

Since 2007 we are developing passive submillimeter-wave video cameras for personal security screening. In contradiction to established portal-based millimeter-wave scanning techniques, these are suitable for stand-off or stealth operation. The cameras operate in the 350GHz band and use arrays of superconducting transition-edge sensors (TES), reflector optics, and opto-mechanical scanners. Whereas the basic principle of these devices remains unchanged, there has been a continuous development of the technical details, as the detector array, the scanning scheme, and the readout, as well as system integration and performance. The latest prototype of this camera development features a linear array of 128 detectors and a linear scanner capable of 25Hz frame rate. Using different types of reflector optics, a field of view of 1x2m(2) and a spatial resolution of 1-2 cm is provided at object distances of about 5-25m. We present the concept of this camera and give details on system design and performance. Demonstration videos show its capability for hidden threat detection and illustrate possible application scenarios.

Passive submillimeter wave imaging is a concept that has been in the focus of interest as a promising technology for security applications for a number of years. It utilizes the unique optical properties of submillimeter waves and promises an alternative to millimeter-wave and X-ray backscattering portals for personal security screening in particular. Possible application scenarios demand sensitive, fast, and fleixible high-quality imaging techniques. Considering the low radiometric contrast of indoor scenes in the submillimeter range, this objective calls for an extremely high detector sensitivity that can only be achieved using cooled detectors. Our approach to this task is a series of passives standoff video cameras for the 350 GHz band that represent an evolving concept and a continuous development since 2007. The cameras utilize arrays of superconducting transition-edge sensors (TES), i.e. cryogenic microbolometers, as radiation detectors. The TES are operate at temperatures below 1K, cooled by a closed-cycle cooling system, and coupled to superconducting readout electronics. By this means, background limited photometry (BLIP) mode is achieved providing the maximum possible signal to noise ratio. At video rates, this leads to a pixel NETD well below 1K. The imaging system is completed by reflector optics based on free-form mirrors. For object distances of 3–10m, a field of view up to 2m height and a diffraction-limited spatial resolution in the order of 1–2cm is provided. Opto-mechanical scanning systems are part of the optical setup and capable frame rates up to 25 frames per second. Both spiraliform and linear scanning schemes have been developed.

Against a background of newly emerged security threats the well-established idea of utilizing submillimeter-wave radiation for personal security screening applications has recently evolved into a promising technology. Possible application scenarios demand sensitive, fast, flexible and high-quality imaging techniques. At present, best results are obtained by passive imaging using cryogenic microbolometers as radiation detectors. Building upon the concept of a passive submillimeter-wave stand-off video camera introduced previously, we present the evolution of this concept in a practical application-ready imaging device. This has been achieved using a variety of measures such as optimizing the detector parameters, improving the scanning mechanism, increasing the sampling speed, and enhancing the camera software. The image generation algorithm has been improved and an automatic sensor calibration technique has been implemented taking advantage of redundancy in the sensor data. The concept is based on a Cassegrain-type mirror optics, an opto-mechanical scanner providing spiraliform scanning traces, and an array of 20 superconducting transition-edge sensors (TES) operated at a temperature of 450-650 mK. The TES are cooled by a closed-cycle cooling system and read out by superconducting quantum interference devices (SQUIDs). The frequency band of operation centers around 350 GHz. The camera can operate at an object distance of 7-10 m. At 9m distance it covers a field of view of 110 cm diameter, achieves a spatial resolution of 2 cm and a pixel NETD (noise equivalent temperature difference) of 0.1-0.4 K. The maximum frame rate is 10 frames per second.

As reported before, 1, 2 Safe VISITOR (Safe VISible, Infrared and Terahertz Object recognition) is a German project to build a passive security camera which visualizes sub-mm wavelengths using cooled bolometer arrays. This camera could be used for a variety of application scenarios, such as airport screenings or to protect military camps. In all cases, a practical instrument requires ease of use, in particular a flexible installation and a straightforward usage by the security personnel.Here we present a new generation of Safe VISITOR designed to meet these requirements. The main condition for an effective operation is a high frame rate of the imager. Safe VISITOR is able to record videos up to 10 Hz, using a small array of superconducting bolometers in combination with an opto-mechanical scanner. The required cooling of the detector array is provided by a commercial pulse tube cooler with a second, self-contained cooling stage. The cooling cycle is completely automated; after 10 hours of initial cooling from room temperature the system can operate quasi-continuously.For imaging, a 50 cm diameter optics is used which is able to provide an object resolution of approximately 1.5 cm at 8 m distance. For a flexible installation, the object distance can be tuned manually between 7 and 10 m. Additionally, video streams from two commercial cameras are fused with the sub-mm stream: a CCD for visible light and a microbolometer for far infrared (14 mu m). This combines the ability of identification of the person under test with the unprecedented temperature resolution at infrared and the almost perfect transmission at sub-mm. To assist a security official, all image data are displayed in various graphic renditions by a unified system software.

We present the concept and experimental set-up of a passive submillimeter-wave stand-off imaging system for security applications. Our ambition is the design of an application-ready and user-friendly camera providing high sensitivity and high spatial resolution at video frame rates. As an intermediate step towards this goal, the current prototype already achieves a frame rate of 10 frames per second and a spatial resolution below 2 cm at 8 m distance. The camera is the result of a continuous development and a unique concept that yielded first high-resolution passive submillimeter-wave images provided by cryogenic sensors in May et al. (2007). It is based on an array of 20 superconducting transition-edge sensors operated at a temperature of 450 mK, a closed-cycle cooling system, a Cassegrain-type optics with a 50 cm main mirror, and an opto-mechanical scanner. Its outstanding features are the scanning solution allowing for high frame rates and the compact and integrated system design.

A new measurement system was built for magnetic prospection in archaeology. The new device extends the capability of fluxgate- and caesium magnetometer-based systems to large-area mapping as well as high magnetic and lateral resolution. The SQUID system passed its first toughness test during a survey in the Peruvian Palpa region in 2005. Within a couple of days an impressive magnetic database of several hectares was created. This georeferenced archaeological and geological information is used for specific excavations and contributes to the comprehension of the historical contexts of the Palpa region.

A geomagnetic field measurement system for the detection of archaeological signatures in the subsoil is presented based on the superconducting quantum interference device (SQUID). The system provides fast mapping of large areas with high magnetic field gradient resolution as well as lateral precision. The acquired data are geographically referenced and also the altitude profile is given. The properties of the system were tested intensively at the large Neolithic double-ring ditch enclosure of Niederzimmern near Weimar, Germany. Differences of the signal acquisition compared with caesium magnetometers are discussed. In the Niederzimmern double-ring ditch enclosure, with an area of 27 ha, archaeological patterns were found only near the gates. These SQUID measurements, together with accompanying excavations, provide a complex picture of the double-ring ditch enclosure, dated about 5600 years old. Copyright (C) 2008 John Wiley & Sons, Ltd.

A unique system for geomagnetic archaeometry is presented. It uses extremely sensitive superconducting quantum interference devices (SQUIDs) as magnetic field sensors, laid out as intrinsic gradiometers. These sensors are mounted on a non-metallic cart, which guarantees smooth movement even at high speeds. Using a differential global positioning system (GPS) together with an inertial system the measured magnetic field gradient data are located on the mapped area with centimetre resolution and the height profile is also provided using the GPS. All data are stored in a data logger and partially online displayed on a laptop computer.At the time of this report, the system is pushed manually and has been tested on a Neolithic double ring ditch near Weimar, Germany. In a gateway through the rings, remains of palisades and buildings have been well resolved, confirming the high sensitivity of the SQUID-based system. An excavation at the ring ditch showed that material with enhanced susceptibility was the origin of the magnetic field gradient signals. Copyright (c) 2007 John Wiley & Sons, Ltd.

Combinatorial chemistry is well suited for the rapid and systematic optimization of molecular properties. The approach is commonly used for the generation of large numbers of compounds which can be applied for the examination of novel materials, catalysts or receptors. However, most frequently assembly of compound libaries is directed to the identification and optimization of novel therapeutic leads to accelerate the drug discovery process. The majority of combinatorial libraries assembled so far was synthesized on solid supports. The advantages of this method are the opportunity to use excesses of reagents driving reactions to completion and the fact that several technologies were invented to automatize and miniaturize these reactions. Beside high throughput parallel synthesis on resin beads, polymeric pins and chips [1], SPOT-synthesis using continuous membranes has been described to be an efficient synthetic approach [2]. The major feature of the latter method is the positionally addressed delivery of small volumes of liquids to a membrane surface. The droplets dispensed by a robot form separate spots which can be considered as micro-reactors provided that a non-volatile solvent system is used (Fig. 1).

Solid phase synthesis, especially spot-synthesis on cellulose membranes is well established for facile preparation of large arrays of biomolecules, e.g. peptides, nucleic acids, peptoides and the subsequent solid and solution phase screening. Despite many good properties of cellulose membranes for some applications this material has a number of limitations such as low chemical and mechanical stability and high concentration of reactive, chemical different hydroxyl groups causing side reactions. Therefore a novel- continuous polymeric material, porous membranes and non-porous materials, was developed based on the chemical and photochemical surface functionalization by grafting of flexible polymer chains carrying the functional and reactive groups for the syntheses. Several classes of compounds e.g. peptides, nucleic acids, peptoides, glucoconjugates and small organic molecules were synthesized using the new continuous polymeric surface.