Identification of particles with Lorentz factor up to 10410^{4} with Transition Radiation Detectors based on micro-strip silicon detectors

This work is dedicated to the study of a technique for hadron identification in the TeV momentum range, based on the simultaneous measurement of the energies and of the emission angles of the Transition Radiation (TR) X-rays with respect to the radiating particles. A detector setup has been built and tested with particles in a wide range of Lorentz factors (from about $10^3$ to about $4 \times 10^4$ crossing different types of radiators. The measured double-differential (in energy and angle) spectra of the TR photons are in a reasonably good agreement with TR simulation predictions.Comment: 31 pages, 12 figures, paper published on Nuclear Instruments & Methods

Performance of 4096 pixel photon counting chip

A 4096 pixel Photon Counting Chip (PCC) has been developed and tested. It is aimed primarily at medical imaging although it can be used for other applications involving particle counting. The readout chip consists of a matrix of 64 x 64 identical square pixels, whose side measures 170 mm and is bump-bonded to a similar matrix of GaAs or Si pixel diodes covering a sensitive area of 1.18 cm . The electronics in each cell comprises a preamplifier, a discriminator with variable threshold and a 3-bit threshold tune as well as 15-bit counter. Each pixel can be individually addressed for electrical test or masked during acquisition. A shutter allows for switching between the counting and the readout modes and the use of a static logic in the counter enables long data taking periods. Electrical tests of the chip have shown a maximum counting rate of up to 2 MHz in each pixel. The minimum reachable threshold is 1400 e with a variation of 350 e rms that can be reduced to 80 e rms after tuning with the 3-bit adjustment. Electical noise at the input is 170 e rms. Several read-out chips have been bump-bonded to 200 mm thick GaAs detectors. Tests with g-rays and b sources have been carried out. A number of objects have been imaged and 260 mm thick aluminium foil which represents a contrast to the surrounding aire of only 1.9% has been correctly imaged

Radiation damage in the LHCb vertex locator

The LHCb Vertex Locator (VELO) is a silicon strip detector designed to reconstruct charged particle trajectories and vertices produced at the LHCb interaction region. During the first two years of data collection, the 84 VELO sensors have been exposed to a range of fluences up to a maximum value of approximately 45 × 1012 1 MeV neutron equivalent (1 MeV neq). At the operational sensor temperature of approximately −7 °C, the average rate of sensor current increase is 18 μA per fb−1, in excellent agreement with predictions. The silicon effective bandgap has been determined using current versus temperature scan data after irradiation, with an average value of Eg = 1.16±0.03±0.04 eV obtained. The first observation of n+-on-n sensor type inversion at the LHC has been made, occurring at a fluence of around 15 × 1012 of 1 MeV neq. The only n+-on-p sensors in use at the LHC have also been studied. With an initial fluence of approximately 3 × 1012 1 MeV neq, a decrease in the Effective Depletion Voltage (EDV) of around 25 V is observed. Following this initial decrease, the EDV increases at a comparable rate to the type inverted n+-on-n type sensors, with rates of (1.43±0.16) × 10−12 V/ 1 MeV neq and (1.35±0.25) × 10−12 V/ 1 MeV neq measured for n+-on-p and n+-on-n type sensors, respectively. A reduction in the charge collection efficiency due to an unexpected effect involving the second metal layer readout lines is observed

Sexually transmitted infections, including HIV, in the Netherlands in 2013

Het aantal mensen dat zich bij een Centrum Seksuele Gezondheid heeft laten testen op een seksueel overdraagbare aandoening (soa) is verder gestegen in 2013. Het percentage mensen met een soa is voor het eerst licht gedaald (met 0,4 procent) sinds 2007. Desondanks blijft dit percentage hoog (14,7 procent). Een goed functionerende soa-monitoring blijft daarom essentieel om zicht te houden op relevante trends, opkomende soa binnen groepen die een grotere kans hebben er een op te lopen, en de effectiviteit van preventieprogramma's. De Centra Seksuele Gezondheid (CSG), voorheen soa-poli's, bieden hoogrisicogroepen de mogelijkheid om zich gratis te laten testen op soa en verstrekken medicatie als er een wordt vastgesteld. Het totaal aantal consulten in 2013 bedroeg 133.585 en is met 10 procent toegenomen ten opzichte van 2012. Van alle bezoekers werden de meeste soa gediagnosticeerd bij mensen die ervoor gewaarschuwd waren dat ze mogelijk een soa hadden opgelopen, mensen jonger dan 25 jaar, migranten uit gebieden waar soa en hiv veel voorkomen (bijvoorbeeld Afrika, Zuid-Amerika of Oost-Europa), of mannen die seks hebben met mannen (MSM). Chlamydia Net als in voorgaande jaren was chlamydia de meest gediagnosticeerde soa bij de CSG in 2013 (15.767 diagnoses). Het percentage mensen dat chlamydia had, daalde licht ten opzichte van 2012 (van 12,2 naar 11,8 procent). Chlamydia werd het meest vastgesteld bij heteroseksuelen, zowel mannen als vrouwen, onder de 25 jaar. Na de uitschieter in 2012 van het aantal en percentage mensen met een agressieve variant van chlamydia, lymphogranuloma venereum, zijn deze cijfers weer afgenomen naar het niveau van de jaren daarvoor (7 procent in 2013). Gonorroe Het percentage personen met een gonorroe-infectie bij de CSG bleef in 2013 stabiel ten opzichte van 2012 (3,6 procent in 2012 en 3,4 procent in 2013), nadat het in de voorgaande jaren licht was gestegen. Deze soa werd het meest gediagnosticeerd bij MSM. Het blijft belangrijk om te volgen of de gonorroe-bacterie resistent raakt tegen de antibiotica die in Nederland voorgeschreven worden, de zogenoemde derde generatie cefalosporines. In diverse Europese landen is deze resistentie waargenomen. Hiv Het aantal personen met een hiv-infectie, gediagnosticeerd bij een van de CSG, is in 2013 gelijk gebleven ten opzichte van 2012 (358 versus 356 in 2012). Het percentage positieve testen daalt sinds 2008: van 3,0 procent naar 1,4 procent bij MSM in 2013. Het percentage mensen dat in een laat stadium van een hiv-infectie bij een hiv-behandelcentrum komt, is de afgelopen jaren gedaald. Het is van belang om tijdig de hiv-diagnose te stellen en zo snel mogelijk de behandeling te starten, omdat hierdoor de gezondheidsschade bij de patiënt verkleind kan worden. Ook neemt door behandeling de besmettelijkheid af, waardoor de kans kleiner is dat hiv wordt overgedragen.In 2013, more people were tested for sexually transmitted infections (STI) at Dutch STI clinics than in previous years. Although the percentage of people with an STI showed a slight decrease (0.4 per cent) for the first time since 2007, it remained high at 14.7 per cent. Effective STI monitoring remains essential for the identification of relevant trends, emerging STIs in high-risk groups, and the effectiveness of prevention programmes. STI clinics offer high-risk groups access to free testing for STI and provide care and treatment if an STI is diagnosed. The total number of consultations in 2013 was 133,585, an increase of 10% compared with 2012. In 2013, STI clinic attendees with an STI were mainly people who reported having been notified of their possible exposure to STI, people aged 20-24, people originating from areas in which STI/HIV is common (e.g. Africa, South America or Eastern Europe), and men who have sex with men (MSM). Chlamydia With 15,767 cases, chlamydia remains the most commonly diagnosed STI in 2013. The percentage of people diagnosed with chlamydia was slightly lower in 2013 than in 2012 (11.8 versus 12.2 respectively). Chlamydia was primarily diagnosed in heterosexuals younger than 25 years old and in both men and women. Following the increase in the number and percentage of lymphogranuloma venereum (LGV; an aggressive variant of chlamydia) infections in 2012, these numbers declined to a level comparable to previous years in 2013. Gonorrhoea Whereas the percentage of people with a gonorrhoea infection slightly had increased in previous years, the percentage remained stable in 2013 (3.4 per cent) compared with 2012 (3.6 per cent). Gonorrhoea was mostly diagnosed in MSM. It remains important to monitor the resistance of the gonorrhoea bacteria against the antibiotic currently recommended in the Netherlands, a third-generation cephalosporin. A rising rate of resistance to this antibiotic has been observed in several European countries. HIVThe number of people diagnosed with HIV at STI clinics in 2013 was similar to that of 2012 (358 versus 356 respectively). Among MSM, the percentage of positive HIV tests decreased from 3.0 per cent in 2008 to 1.4 per cent in 2013. The percentage of HIV-positive people who were diagnosed at a late stage of the infection has decreased in previous years. Early diagnosis and treatment of an HIV infection is important because of individual health benefits and the potential reduction of HIV transmission

Bacterial and fungal co-occurrence patterns in agricultural soils amended with compost and bokashi

Plant science

Effects of sterilization and maturity of compost on soil bacterial and fungal communities and wheat growth

Composts are commonly used as soil amendments to sustain and improve the functionality of agricultural soil. Compost has abiotic (organic matter [OM], nutrients) and biotic characteristics (microorganisms) and both can influence the soil microbiome. The abiotic and biotic characteristics of compost, in turn, depend on properties of the compost such as maturity. Few studies have investigated the relative effects of abiotic and biotic components of compost on the soil microbial community and crop growth. To bridge this gap, we used a full-factorial design with sterile and live composts that differed in maturity (fresh, intermediate, mature) that were added to sterile and live soil to investigate the separate role of abiotic and biotic characteristics of composts on the resulting soil microbial community and on wheat growth. We found that the changes in the soil microbial community were mainly due to the input of compost with the presence of microorganisms rather than due to the abiotic properties of compost. The majority of the compost-associated microorganisms (more than 70% for bacteria and 90% for fungi) were detected in the soil in the presence of native soil microorganisms. Elimination of native soil microorganisms by sterilization enhanced the prevalence and abundance of compost-associated microorganisms. Adding fresh compost increased wheat biomass production, but the positive effects of compost on plant growth were strongest when sterile composts were used. Hence, our study reports that compost-associated microorganisms are essential to modify soil microbial community but may not benefit crop growth. This highlights the importance of understanding the role of abiotic and biotic properties of composts as common soil amendments on improving the functioning of agricultural soil.Plant science

Long-term performance of a plant microbial fuel cell with Spartina anglica

The plant microbial fuel cell is a sustainable and renewable way of electricity production. The plant is integrated in the anode of the microbial fuel cell which consists of a bed of graphite granules. In the anode, organic compounds deposited by plant roots are oxidized by electrochemically active bacteria. In this research, salt marsh species Spartina anglica generated current for up to 119 days in a plant microbial fuel cell. Maximum power production was 100 mW m−2 geometric anode area, highest reported power output for a plant microbial fuel cell. Cathode overpotential was the main potential loss in the period of oxygen reduction due to slow oxygen reduction kinetics at the cathode. Ferricyanide reduction improved the kinetics at the cathode and increased current generation with a maximum of 254%. In the period of ferricyanide reduction, the main potential loss was transport loss. This research shows potential application of microbial fuel cell technology in salt marshes for bio-energy production with the plant microbial fuel cell

RD39 Status Report 2009

RD39 Status Report 2009. CERN RD39 Collaboration is developing super-radiation hard cryogenic silicon detectors for applications of LHC experiments and their future upgrades. The activities of RD39 Collaboration were focused in 2009 on concept of charge injected detector (CID)