Novel types of micro-pixel avalanche photodiodes (MAPDs) and their principle of performance are analyzed. The first design contains a common silicon wafer on which a matrix of independent p–n ...junctions (micro-pixels) with individual surface resistors are created. The individual resistors provide a local suppression of the avalanche process and discharge each micro-pixel to a common metal grid (electrode). The second design is an avalanche photodiode with independent micro-pixels in which the local suppression of the avalanche process is carried out due to the limited conductivity of individual surface drift channels formed along the silicon–silicon oxide boundary. This design is considered as a prototype for a future super-fast avalanche CCD matrix capable to work in a single-photon detection mode. The third design contains a matrix of deep buried multilayer pixels with an individual suppression of the avalanche process in independent vertical channels.
The Panda experiment is a key experiment at FAIR – European Facility for Antiproton and Ion Research, which is in the development stage in Darmstadt (Germany). The physical program of the experiment ...is focused on the search for exotic particles, research on hadron spectroscopy, the structure of nucleons, nuclear-matter effects, hypernuclei, and in other areas. New experimental forms of matter predicted by theory – glueballs and hybrids – are of great interest. They have not yet been observed. The PANDA facility will be assembled in the storage ring of the HESR antiproton beam. Antiprotons with energy from 1.5 to 15 GeV will be accumulated in the ring. Up to 2·10
7
interactions/sec are expected on the internal hydrogen (cluster or corpuscular) target. In addition to the high luminosity of the experiment (2·10
32
cm
–2
·sec
–1
), the beam will be monochromatic. Because of stochastic and electronic cooling, pulsed stretching of the beam is expected to be at the level 10
–4
–10
–5
, which makes it possible to measure the mass of the particles with record high resolution 100 keV. Domestic institutes are participating in the development of the PANDA facility.
The ferrite/superconductor (FS) structure composed from the separate ferrite garnet Y
3Fe
5O
12 epitaxial layers and superconducting films was used for development of such microwave devices as ...tunable pass-band filter, phase-shifter and delay line. Application of superconducting layer decreases the microwave losses and it provides new functions of magnetostatic waveguide FS structures. The central frequency of band-pass filter is tuned from 1.5 up to 3 GHz; bandwidth can be regulated by the geometry of antenna transducers (from 30 up to 300 MHz); band insertion loss is about 1.5–3 dB.
The design and operation principle of a novel microchannel avalanche photodiode with the short recovery time of parameters are considered in this Letter. A distinctive feature of the new device is ...that at the operating potential on it, the
n
+
regions (pixels) deeply submerged into the epitaxial layer with
p
-type conductivity are completely depleted; thus, the possibility of accumulation of multiplied charge carriers in them is carried out. This enables attaining the recovery time of pixels in the device of ~50 ns at photocurrent amplification factor equal to 250.
The main goal of this work is to study the possibility of detecting alpha particles with a micropixel avalanche photodiode (MAPD) in combination with Lutetium Fine Silicate (LFS) scintillators (500 ...μm thick). The results show that alpha detectors based on the MAPD are expected to be useful in many applications: public security (associated particle imaging for explosives and drugs detection), radioactive contamination monitoring in various environments, and detection of charged particles from nuclear reactions.
Avalanche Microchannel PhotoDiodes (AMPDs) are solid state photodetectors with high internal gain and a density of independent channels up to 10
4/mm
2. They are potential substitutes for ...photomultiplier tubes in a wide variety of applications in nuclear physics and nuclear medicine, especially when fine segmentation of the detectors and their operation in high magnetic fields is required.
In this work, we study the performance of a detector based on a LYSO (2×2×10
mm
3) scintillation crystal and AMPD at detection of 511
keV γ-quanta. The detector shows linear energy response, an energy resolution of ∼12%, and sub-nanosecond time resolution. These characteristics are encouraging for using AMPDs in detector systems of positron emission tomographs (PET) of the next generation.
A 64-element array was assembled out of 3×3-mm
2 Micro-pixel Avalanche Photodiodes (MAPD) for use in the next-generation PET scanners. Spatial distribution of photo-response across the surface of a ...single element as well as bias voltage variation between elements of the array was studied.
The form factor of A(o)(b) baryons is estimated using 3.46 x 10(6) hadronic Z decays collected by the DELPM experiment between 1992 and 1995. Charmed A(c)(+) baryons fully reconstructed in the ...pK(-)pi(+), pK(o)(s), and Api(+)pi(+)pi(-) modes, are associated to a c S lepton with opposite charge in order to select A(o)(b) --> A(c)(+)l(-)v(l) decays. From a combined likelihood and event rate fit to the b C distribution of the Isgur-Wise variable w, and using the Heavy Quark Effective Theory (HQET), the slope of the b-baryon form factor is measured to be p(2)=2.03+/-0.46(stat)(-1.00)(+0.72)(syst). The exclusive semileptonic branching fraction Br(A(b)(o) --> A(c)(+)l(-)v(l)) can be derived from p(2) and is found to be (5.0(-0.8)(+1.1)(stat)(-1.2)(+1.6) (syst))%. Limits on other branching fractions are also obtained. (C) 2004 Published by Elsevier B.V.
The charmed strange baryon Xi(c)(0) was searched for in the decay channel Xi(c)(0) -> Xi(-)pi(+), and the beauty strange baryon Xi(b) in the inclusive channel Xi(b) -> Xi(-)l(-)(nu) over barX, using ...the 3.5 million hadronic Z events collected by the DELPHI experiment in the years 1992-1995. The Xi(-) was reconstructed through the decay AT, using a constrained fit method for cascade decays. An iterative discriminant analysis was used for the Xi(c)(0) and Xi(b) selection. The production rates were measured to be f(Xi c)(0) x BR(Xi(c)(0) -> Xi(-)pi(+) = (4.7 +/- 1.4(stat.) +/- 1.1(syst.)) x 10(-4) per hadronic Z decay, and BR(b -> Xi(b))xBR(Xi(b) -> Xi(-)l(-)X) = (3.0 +/- 1.0(stat.) +/- 0.3(syst.)) x 10(-4) for each lepton species (electron or muon). The lifetime of the Xi(b) baryon was measured to be tau(Xi b) = 1.45(-0.43)(+0.55)(stat.)+/- 0.13(syst.) ps. A combination with the previous DELPHI lifetime measurement gives tau(Xi b) = 1.48(-0.31)(+0.40)(stat.)+/- 0.12(syst.) ps.
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