Plasduino: an inexpensive, general purpose data acquisition framework for educational experiments

Based on the Arduino development platform, Plasduino is an open-source data acquisition framework specifically designed for educational physics experiments. The source code, schematics and documentation are in the public domain under a GPL license and the system, streamlined for low cost and ease of use, can be replicated on the scale of a typical didactic lab with minimal effort. We describe the basic architecture of the system and illustrate its potential with some real-life examples.Comment: 11 pages, 10 figures, presented at the XCIX conference of the Societ\`a Italiana di Fisic

Reading a GEM with a VLSI pixel ASIC used as a direct charge collecting anode

In MicroPattern Gas Detectors (MPGD) when the pixel size is below 100 micron and the number of pixels is large (above 1000) it is virtually impossible to use the conventional PCB read-out approach to bring the signal charge from the individual pixel to the external electronics chain. For this reason a custom CMOS array of 2101 active pixels with 80 micron pitch, directly used as the charge collecting anode of a GEM amplifying structure, has been developed and built. Each charge collecting pad, hexagonally shaped, realized using the top metal layer of a deep submicron VLSI technology is individually connected to a full electronics chain (pre-amplifier, shaping-amplifier, sample and hold, multiplexer) which is built immediately below it by using the remaining five active layers. The GEM and the drift electrode window are assembled directly over the chip so the ASIC itself becomes the pixelized anode of a MicroPattern Gas Detector. With this approach, for the first time, gas detectors have reached the level of integration and resolution typical of solid state pixel detectors. Results from the first tests of this new read-out concept are presented. An Astronomical X-Ray Polarimetry application is also discussed.Comment: 11 pages, 14 figures, presented at the Xth Vienna Conference on Instrumentation (Vienna, February 16-21 2004). For a higher resolution paper contact [email protected]

Greenhouse gas emissions in the agricultural phase of wine production in the Maremma rural district (Tuscany, Italy).

In recent years, there has been an increasing interest from retailers, industries and environmental associations in estimating the life cycle of greenhouse gases emitted in the atmosphere from everyday products and services, also known as carbon footprint (CF). Life cycle assessment (LCA) is the most common methodology used to evaluate the environmental impact of a product. This approach was largely used in many industrial sectors and was also recently applied to quantify the environmental impact of the agri-food chain. Within agri-food products, wine is one of the most analysed, both for its importance in economic production and in the world distribution market. The present study is a part of the Carbon Label Project carried out in the wine production chain in the Maremma rural district (Tuscany, Italy). The project assessed the greenhouse gas (GHG) emissions from wine production for labelling purposes. Here, we evaluated the environmental performances of four high quality wines for carbon labelling. The international standards ISO 14040, ISO 14044, and the Product Category Rules (PCR) Wine from Fresh Grapes (except sparkling wine) and Grape Must for the Environmental Product Declaration (EPD) certification, specifically for Climate Declaration, were used in order to carry out our analyses. The functional unit (FU) used here was one 0.75 L bottle of wine. The system boundaries were set from the vineyard planting to the distribution and waste disposal. The global warming potential (GWP) of four investigated wines was found to lie between 0.6 and 1.3 kg CO2-eq./bottle, showing a value comparable with literature. With all the four wines analysed, the agricultural phase covered, on average, 22% of the total GWP/bottle, while the main impact was in the production of the glass bottle. The results showed that the vineyard-planting phase has a significant impact on the wine CF, thus it has to be considered in the life cycle, while in literature it is frequently omitted. On the contrary, the pre-production phase did not present a relevant impact. The use of nitrogen fertilisers, the grapes’ yield and N2O emissions were the parameters that mostly affected the carbon footprint in the agricultural phase, as underlined by the sensitivity analysis

The Micro-Groove Detector

We introduce the Micro-Groove Detector (MGD), a new type of position-sensitive gas proportional counter produced using advanced printed circuit board (PCB) technology. The MGD is based on a thin kapt on foil, clad with gold-plated copper on both sides. An array of micro-strips at a typical pitch of 200um is defined on the top metal layer. Using as a protection mask the metal left after the patter ning, charge amplifying micro-grooves are etched into the kapton layer. These end on a second micro-strip pattern which is defined on the bottom metal plane. The two arrays of micro-strips can have a n arbitrary relative orientation and so can be used for read-out to obtain 2-D positional information. First results from our systematic assessment of this device are reported: gas gain > 15000, rat e capability above 10^6mm-2s-1, energy resolution 22% at 5.4 keV, no significant charging or aging effects up to 5mC/cm, full primary charge collection efficiency even at high drift fields

A Stringy Mechanism for A Small Cosmological Constant

Based on the probability distributions of products of random variables, we propose a simple stringy mechanism that prefers the meta-stable vacua with a small cosmological constant. We state some relevant properties of the probability distributions of functions of random variables. We then illustrate the mechanism within the flux compactification models in Type IIB string theory. As a result of the stringy dynamics, we argue that the generic probability distribution for the meta-stable vacua typically peaks with a divergent behavior at the zero value of the cosmological constant. However, its suppression in the single modulus model studied here is modest.Comment: 36 pages, 8 figure

The WELL Detector

We introduce the WELL detector, a new type of position-sensitive gas proportional counter produced using advanced printed circuit board (PCB) technology. The WELL is based on a thin kapton foil, copp erclad on both sides. Charge amplifying micro-wells are etched into the first metal and kapton layers. These end on a micro-strip pattern which is defined on the second metal plane. The array of micr o-strips is used for read-out to obtain 1-D positional information. First results from our systematic assessment of this device are reported

Thoughts on Galileo’s Work

J’analyserai des déclarations et des idées proposées par Galilée dans son Sidereus Nuncius et j’en proposerai des interprétations non conventionnelles. Je vais essayer de montrer qu’avec un esprit logique et de nouvelles hypothèses, il est possible de parvenir à de nouvelles interprétations possibles de la pensée de Galilée.I wish to analyse certain statements and ideas proposed by Galileo Galilei in his Sidereus Nuncius and will provide non-conventional interpretations of them. I will try to show that with logical connection and new hypothesis, it is possible to make some new possible interpretations of Galileo’s thoughts

A Two-Stage, High Gain Micro-strip Detector

A two stage position-sensitive gas proportional counter has been constructed by tightly coupling a Gas Electron Multiplier (GEM) with a Micro-Groove Detector (MGD). The GEM was used as the first amplifying stage and was optimised to transmit close to 100~\% of the primary charge even at very high drift fields (10~kV/cm). Very narrow GEM--MGD seperations (0--600~$\mu$m) were used so that the active volume of the detector is still very thin (3--3.6~mm) and the required drift field could be maintaine d using an acceptable drift voltage (around 4000~V). Very high combined gains (up to 3~$\times$10$^5$) were obtained with this system. The detector was found to be spark-free in the presence of HIPs (alpha particles) up to gains in excess of 10,000

The CMS Micro-strip Gas Chamber Project: Development of a high resolution tracking detector for harsh radiation environments

Thirty-two large area Micro-Strip Gas Chambers were tested in a high intensity, 350~MeV pion beam at PSI to prove that we had reached a Milestone for the Compact Muon Solenoid (CMS) experiment. The particle rate was approximately 6 kHz/mm2, distributed over the whole active area of the detectors, and this rate was maintained for a total integrated time of 493 hours. All of the chambers were operated with signal-to-noise values at or above that corresponding to 98 % hit detection efficiency at CMS; the average S/N was 31. No indications of any gain instabilities or ageing effects were observed. In the official 3-week Milestone period, three strips from a total of 16384 were damaged, a result which is twenty times lower than the minimal requirement for CMS. The spark rate of the detectors was very low and decreased with time to an average of one spark per chamber per day. The cathode voltages of 24 of the chambers were increased over a one week period to investigate the behaviour of the detectors at higher gains; the maximum S/N value was 2.4 times that at the normal working point. No significant increase in spark rate or strip loss rate was detected and the chambers operated stably. The detector efficiencies and imaging capabilities were also investigated. The MSGC design features and the assembly and test methodologies that enabled us to achieve these results are reported