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The goal of the Hui Malama o ke Kai project was the development of a community-based youth program that supported the prevention of youth violence and substance use among 5th- and 6th-grade students from a predominantly Hawaiian community. This program's development included engaging with a variety of community partners and mobilizing parents through the youths' cultural development. Recommendations for working with Hawaiians and other indigenous peoples include having program evaluators work more intimately with program participants and developing program components that address ethnic identity and family engagement. In doing so, youth programs with indigenous peoples can also galvanize small communities that are coping with destructive social concerns.

Results from SINTEF's research on radiation hardness of silicon detectors, thin silicon detectors, silicon drift devices, reach-through avalanche photodiodes, and detectors with thin dead layers are presented.

A “single-sided” microstrip detector with n-type strip implants in n-type silicon substrate materials has been developed for use in high luminosity vertex tracker experiments. This technology has been chosen to make a detector which will operate satisfactorily well beyond the radiation dose which converts the substrate to p-type material. This full-size detector of dimensions 60 mm × 60 mm has 1025 strips (with 512 read-out strips) biased with polysilicon resistors. Separate “p-stop” implants between the strips isolate the strips from each other electrically. These individual p-stops are implemented in order to reduce the detector noise. A combination of silicon oxide and silicon nitride gives a very reliable dielectric layer for the coupling capacitors, which yields a low fraction of defective read-out strips. The backside p-n-junction area is surrounded by a high-stability guard which makes it possible to operate the detector at bias voltages corresponding to several times the depletion voltage. Preliminary irradiation tests carried out in order to determine the detector design's suitability for the experiments at the CERN-Large Hadron Collider have shown that the detectors are not fatally damaged after a radiation dose of 2 × 1014 protons cm−2.

The performance and stability of silicon diode detectors can be improved by implementing guard ring structures around the active detector area. The purpose of this work is to study design parameters influencing the performance of multiguard structures, especially the effect of metal field plates. An important feature is the potential distribution in the multiguard ring structure which depends on the bulk doping concentration, the oxide charge, the size of the gap between guard rings and the field-plate design. We have made a systematic investigation of the effect of distance between floating p+ guard rings with two different metal field plate designs. We have also varied the width of the field plates and studied the effect of gamma irradiation. Numerical simulations have been done to compare with results from the experimental potential distributions between guard rings.

Silicon microstrip detectors can be biased with polysilicon resistors or Field Effect Transistor (FET) biasing structures. Polysilicon resistors are radiation hard, but using the FET biasing principle reduces processing costs and can give better noise performance. A set of microstrip detectors has been manufactured with a standard radiation sensor process in order to assess the radiation hardness of punch-through and FET biasing. Eight different bias geometry designs were used in order to study the effects of bias gap lengths and strip end geometries on the detector characteristics. The test detectors were irradiated at several dose levels up to 75 kGy with a 60Co source. Initially the devices had very low oxide charge (3 × 1010 cm−2) and leakage current levels (60 pA per strip). The dynamic resistance was in the 1 GΩ range, which is higher than the values which can be achieved by conventional polysilicon resistors. Radiation exposure gave significant increases in the leakage current of the devices. This causes large reductions in the dynamic resistance, and detector performance will degrade. The degradation due to increased leakage current was present for all strip end geometries, and it could not be compensated by changing the gate voltage.

A 1 mm thick silicon pad detector has been developed for the Atlas Positron Experiment (APEX) [1,2]. This experiment requires efficient detection of positrons and electrons with energies up to 1 MeV with an energy resolution of better than 10 keV and time resolution of less than 2 ns. To satisfy these requirements, the detectors should be 1 mm thick with low leakage current and be capable of operation at voltages greater than needed for full depletion. To enhance the charge collection time, the detectors should also withstand cooling to liquid nitrogen temperature. These requirements have been satisfied using diodes manufactured on high resistivity silicon in combination with a segmented guard ring structure (multiguard) and a process optimized to reduce the bulk generated leakage current. A room temperature leakage current of 1 nA/cm2 was achieved and an energy resolution of 3.6 keV FWHM was measured with 30 pF input capacitance on a charge sensitive preamplifier. At −130°C with 90 pF input capacitance an energy resolution of 3.4 keV FWHM and a time resolution of 1.2 ns was measured for 500 keV electrons in coincidence with gamma rays detected in a BaF2 scintillator detector. Results from the evaluation of different designs and process approaches are discussed.

Measurements have been carried out on the temperature dependence of the behaviour of two types of drift device: photodiodes and position sensitive drift chambers with segmented anode and cathode structures. Leakage currents and electron mobility have been investigated at low temperature for the drift photodiodes. Self-triggering has been achieved for the position sensitive drift chambers using 60 keV photons, and differences in arrival time between the prompt trigger signal from the cathode and the delayed anode signal have been studied as a function of drift distance and temperature.

Silicon drift chambers with subdivided anode structures intended for two-dimensional position measurement have been produced. These devices use implanted resistor chains to form the drift and have orthogonal strips on the reverse side intended for self-triggering capability. An important consequence of the design is that low drift fields must be used (≤ about 70 V/cm). We present results based on detailed position-response studies which show significant distortions of both pulse height and drift time characteristics. The causes of the distortions will be considered.

Capacitively coupled Si strip detectors with readout on both the p-side and the n-side have been developed. A novel scheme to separate strips ohmically on the n-side by means of field depletion via a suitable potential applied to the readout strips has been successfully demonstrated. Results on the spatial resolution of these detectors for both sides measured in a high energy beam are presented. The spatial resolution of the n-side has been measured at different incident angles of the beam tracks with respect to a vertical plane through the n + strips at 0°, 20° and 40°.

Low capacitance photodiodes based on the principle of the solid state drift chamber have been constructred and tested. The devices are based on a cellular design with an anode at the centre of each of five cells allowing electrons liberated by ionisation to drift up to 1 mm to the readout strip. Results on the performance of the detectors, including leakage current, capacitance and drift properties, are presented and compared with simulations. A second series drift photodiodes have been processed which incorporate improvements based on results acquired from the first design. They have leakage currents of a few nA and shorter drift times at the periphery of the drift cells. We present measurements showing the performance of the new devices.