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The 3α (triple-alpha) process leading to the formation of stable carbon in the Universe is one of the most important nuclear astrophysical processes. The radiative width of the so called Hoyle-state, involving the 7.654 MeV E0 and the 3.215 MeV E2 transitions, is known with 12.5% accuracy. We report on the development of a Si(Li)-detector array for a new magnetic pair spectrometer, which will be used for the measurement of the pair conversion of the E0 and E2 transitions from the Hoyle-state. The results of the final detector tests will be presented.

Results of the first measurements on HPGe- and Si(Li)-detectors with an one dimensional fine pitch strip structure are presented. The position-sensitive structures were fabricated on implanted boron contacts by means of photolithography with a subsequent plasma etching. A group of 5 neighbouring strips of both detector types was examinated concerning the reverse current, resistance between a position-element and the neighbourhood and the response to the photons up to 60 keV.

This paper presents comparative analysis of different processing errors when modeling speech signal generating system simulated by neural network auto regressive with extra input (NNARX). Feed forward NNs were used. Vowels were taken to train and test models. Gradient descent algorithm (GDA) is used for the training, back propagation algorithm (BPA) for the testing, and optimal brain surgeon (OBS) for the NN pruning. Results are given in Tables I-IV, and compared in conclusion

At Lawrence Livermore National Laboratory, we are pursuing the development of a gamma-ray imaging system using the Compton effect. We have built our first generation hybrid Compton imaging system, and we have conducted initial calibration and image measurements using this system. In this paper, we present the details of the hybrid Compton imaging system and initial calibration and image measurements

During the development of double-sided microstructured Si(Li) detectors thin Li-doped contacts with effective thicknesses below 10 /spl mu/m could be created. The effective thickness was determined by evaluating the measured energy loss of /spl alpha/-particles entering the detector through the Li-doped contact. Extensive examinations have been performed to find the correlation between the effective thicknesses determined with the help of /spl alpha/-particles and the thicknesses based on the measured distribution of the Li-ions in the Li-diffused layers. Pronounced discrepancies were found in the relation between the effective thicknesses and the thicknesses of the removed layer during the thinning process. In any case, the effective thickness was considerably smaller than the thickness estimated from the distribution of the Li-ions. The dependence of the effective thickness on the bias voltage and the temperature was studied. A possible explanation of the relatively small effective thicknesses based on the internal electric field inside the Li-doped layer caused by the concentration gradient is presented. The technique to create Li-doped layers with an effective thickness smaller than 5 /spl mu/m is described. In this way, the transmission Si(Li) detectors with the effective dead layers being smaller than 0.1% of their thickness can be realized (patent is filed).

To study the stripping injection into the cooler synchrotron storage ring COSY, the cross sections for the charge exchange reaction H/sub 2//sup +/ to 2p+e/sup -/, H/sub 2//sup +/ to H/sup 0/+p, etc. and H/sup -/ to p+2e/sup -/ in carbon and aluminum oxide foils were measured at 30 and 40 MeV/amu. The data are presented in terms of all charge exchange cross sections involved. Monte Carlo calculations for a special working point of COSY demonstrate the efficiency of this method to fill the ring. >

With the ANKE spectrometer at the COoler SYnchrotron COSY Juelich the mesonic structure of the nucleon will be studied in polarized proton-proton and proton-deuteron collisions. The identification and tracking of low energy protons permits using deuterium as an effective neutron target. For this purpose, modular self-triggering tracking telescopes built up by double-sided silicon strip detectors inside the accelerator ultra-high vacuum have been developed. Their basic features are DeltaE/E proton identification from 2.5-40 MeV and particle tracking over a wide dynamic range, either 2.5 MeV spectator protons or minimum ionizing particles. By the use of self-triggering read-out chips, the telescopes identify a particle passage within 100 ns and therefore allow the possibility of a fast hit pattern recognition. In combination with a read-out pitch of similar to200 mum, they provide a high rate capability. The recent development of very thick (greater than or equal to5 mm) double-sided microstructured Si(Li) and very thin (less than or equal to65 mum) double-sided Si-detectors provides the use of the telescopes over a wide range of particle energies.

A new technique for manufacturing double-sided structured Si(Li) detectors has been established. The position-sensitive structure on the implanted p/sup +/-contact can be made smaller than 100 /spl mu/m by photolithography followed by plasma etching of grooves to separate the position elements. By modifying this technique position-sensitive structures on a thin (/spl sim/30 /spl mu/m) Li-diffused contact were created. Areas of 50 mm /spl times/ 50 mm were divided into 50 or 100 strips with a pitch of 1 mm or 500 /spl mu/m, respectively. The strips were separated by /spl sim/35-/spl mu/m-deep and /spl sim/50-/spl mu/m-wide grooves. Measurements of the electrical resistance of the grooves and reverse current of the strips are presented. Charge splitting on the adjacent strips shows practically no charge loss through the groove. Small pixel effects are demonstrated on a Li-diffused contact (100 strips with the pitch of 500 /spl mu/m) and on the first double-sided Si(Li) detector (50 /spl times/ 50 strips with a pitch of 1 mm). By measuring the relative time distribution of the signal from both contacts it is possible to obtain some three-dimensional imaging capability.