APDs as Single-Photon Detectors for Visible and Near-Infrared Wavelenghts down to Hz Rates

For the SPECTRAP experiment at GSI, Germany, detectors with Single-Photon counting capability in the visible and near-infrared regime are required. For the wavelength region up to 1100 nm we investigate the performance of 2x2 mm^2 avalanche photo diodes (APDs) of type S0223 manufactured by Radiation Monitoring Devices. To minimize thermal noise, the APDs are cooled to approximately -170 deg. C using liquid nitrogen. By operating the diodes close to the breakdown voltage it is possible to achieve relative gains in excess of 2x10^4. Custom-made low noise preamplifiers are used to read out the devices. The measurements presented in this paper have been obtained at a relative gain of 2.2x10^4. At a discriminator threshold of 6 mV the resulting dark count rate is in the region of 230/s. With these settings the studied APDs are able to detect single photons at 628 nm wavelength with a photo detection efficiency of (67+-7)%. Measurements at 1020 nm wavelength have been performed using the attenuated output of a grating spectrograph with a light bulb as photon source. With this setup the photo detection efficiency at 1020 nm has been determined to be (13+-3)%, again at a threshold of 6 mV.Comment: 14 pages, 9 figures, submitted to Journal of Instrumentatio

APDs as Single-Photon Detectors for Visible and Near-Infrared Wavelenghts down to Hz Rates

For the SPECTRAP experiment at GSI, Germany, detectors with Single-Photon counting capability in the visible and near-infrared regime are required. For the wavelength region up to 1100 nm we investigate the performance of 2x2 mm^2 avalanche photo diodes (APDs) of type S0223 manufactured by Radiation Monitoring Devices. To minimize thermal noise, the APDs are cooled to approximately -170 deg. C using liquid nitrogen. By operating the diodes close to the breakdown voltage it is possible to achieve relative gains in excess of 2x10^4. Custom-made low noise preamplifiers are used to read out the devices. The measurements presented in this paper have been obtained at a relative gain of 2.2x10^4. At a discriminator threshold of 6 mV the resulting dark count rate is in the region of 230/s. With these settings the studied APDs are able to detect single photons at 628 nm wavelength with a photo detection efficiency of (67+-7)%. Measurements at 1020 nm wavelength have been performed using the attenuated output of a grating spectrograph with a light bulb as photon source. With this setup the photo detection efficiency at 1020 nm has been determined to be (13+-3)%, again at a threshold of 6 mV.Comment: 14 pages, 9 figures, submitted to Journal of Instrumentatio

APDs as Single-Photon Detectors for Visible and Near-Infrared Wavelenghts down to Hz Rates

For the SPECTRAP experiment at GSI, Germany, detectors with Single-Photon counting capability in the visible and near-infrared regime are required. For the wavelength region up to 1100 nm we investigate the performance of 2x2 mm^2 avalanche photo diodes (APDs) of type S0223 manufactured by Radiation Monitoring Devices. To minimize thermal noise, the APDs are cooled to approximately -170 deg. C using liquid nitrogen. By operating the diodes close to the breakdown voltage it is possible to achieve relative gains in excess of 2x10^4. Custom-made low noise preamplifiers are used to read out the devices. The measurements presented in this paper have been obtained at a relative gain of 2.2x10^4. At a discriminator threshold of 6 mV the resulting dark count rate is in the region of 230/s. With these settings the studied APDs are able to detect single photons at 628 nm wavelength with a photo detection efficiency of (67+-7)%. Measurements at 1020 nm wavelength have been performed using the attenuated output of a grating spectrograph with a light bulb as photon source. With this setup the photo detection efficiency at 1020 nm has been determined to be (13+-3)%, again at a threshold of 6 mV.Comment: 14 pages, 9 figures, submitted to Journal of Instrumentatio

Containing the Not-Invented-Here Syndrome in external knowledge absorption and open innovation: The role of indirect countermeasures

This paper builds new theory and provides supporting evidence to contain the Not-Invented-Here Syndrome (NIHS) – a persistent decision-making error arising from an attitude-based bias against external knowledge. Conceptually, we draw on the 4i framework of organizational learning to develop a novel process perspective on NIHS. This allows us not only to unpack how and where NIHS impedes organizational learning, but also to identify the key requirements for effective NIHS countermeasures. Importantly, countermeasures fall into two categories: those that seek to change the negative attitude directly (direct NIHS countermeasures) and those that seek to attenuate the behavioral impact of negative attitudes without addressing the attitudes as such (indirect NIHS countermeasures). While the evidence base on direct NIHS countermeasures has grown over the last decade, indirect NIHS countermeasures have received little research attention. To address this gap, we adopt a mixed methods research design composed of two complementary empirical studies – the first qualitative and the second quantitative. Study 1 explores the prevalence of distinct NIHS countermeasures in collaborative R&D practice. Based on 32 interviews and three focus group meetings with R&D employees, we find that a broad array of primarily direct NIHS countermeasures is employed in R&D practice. Study 2 addresses the scarcity of scholarly and managerial insights on indirect NIHS countermeasures by testing the effectiveness of perspective taking as a debiasing technique to contain negative attitudes at the level of the individual. Based on quantitative survey data from 565 global R&D projects, it provides empirical evidence not only for the prevalence and negative effects of NIHS on project success as mediated by external knowledge absorption, but also for the effectiveness of perspective taking as an exemplary indirect NIHS countermeasure

Genotyping of Chlamydophila psittaci in Human Samples

Chlamydophila (formerly Chlamydia) psittaci genotypes A, B, C, and a new genotype most similar to the 6BC type strain were found in 10 humans with psittacosis by outer membrane protein A gene sequencing. Genotypes B (n = 3) and C (n = 1) are endemic in nonpsittacine European birds. These birds may represent an important part of the zoonotic reservoir