Search results for "Optoelectronics"
showing 10 items of 2306 documents
Recent results from the ATLAS SCT irradiation programme
2000
Abstract The irradiation facility at the CERN proton synchrotron, set up to irradiate full-size prototypes of silicon microstrip detectors for the ATLAS semiconductor tracker, is described and measurements of the detector currents during irradiation are reported. The detector dark currents can be described by bulk radiation damage models demonstrating the radiation hardness of the detector design and allowing the current damage factor α and the acceptor introduction term β to be determined. Results from testbeam studies of a module with an irradiated detector and binary readout in a magnetic field and with the beam incident over a range of angles are reported. The hit efficiency and spatial…
Performance Studies of Pixel Hybrid Photon Detectors for the LHCb RICH Counters
2006
The Pixel Hybrid Photon Detector is a vacuum tube with a multi-alkali photo cathode, high voltage cross-focused electron optics and an anode consisting of a silicon pixel detector bump-bonded to a readout CMOS electronic chip fully encapsulated in the device. The Pixel HPD fulfils the requirements of the Ring Imaging Cherenkov counters of the LHCb experiment at LHC. The performances of the Pixel HPD will be discussed with reference to laboratory measurements, Cherenkov light imaging in recent beam tests, image distortions due to a magnetic field.
Targets on superhydrophobic surfaces for laser ablation ion sources
2012
Target preparation techniques for a laser ablation ion source at the Penning-trap mass spectrometer TRIGA-TRAP have been investigated with regard to future experiments with actinides. To be able to perform mass measurements on these nuclides considering their limited availability, an efficient target preparation technique is mandatory. Here, we report on a new approach for target production using backings, which are pretreated in a way that a superhydrophobic surface is formed. This resulted in improved targets with a more homogeneous distribution of the target material compared to standard techniques with unmodified backings. It was demonstrated that the use of these new targets in a laser…
NTD-GE-based microcalorimeter performance
2000
Our group has been developing x-ray microcalorimeters consisting of neutron transmutation doped (NTD) germanium thermistors attached to superconducting tin absorbers. We discuss the performance of single pixel x-ray detectors, and describe an array technology. In this paper we describe the read-out circuit that allows us to measure fast signals in our detectors as this will be important in understanding the primary cause of resolution broadening. We describe briefly a multiplexing scheme that allows a number of different calorimeters to be read out using a single JFET. We list the possible causes of broadening and give a description of the experiment which best demonstrates the cause of the…
Multi-pixel Geiger-mode avalanche photodiode and wavelength shifting fibre readout of plastic scintillator counters of the EMMA underground experiment
2009
The results of a development of a scintillator counter with wavelength shifting (WLS) fibre and a multi-pixel Geiger-mode avalanche photodiode readout are presented. The photodiode has a metal-resistor-semiconductor layered structure and operates in the limited Geiger mode. The scintillator counter has been developed for the EMMA underground cosmic ray experiment.
Use of aluminum nitride for UV radiation dosimetry
2007
Abstract An investigation of AlN ceramics for applications in UV radiation detection shows the advantages of using the 480 nm emission band for optically stimulated luminescence signal detection instead of the previously used 400 nm emission band since the rate of decrease of the response signal at room temperature is lower than that of the 400 nm band, and its excitation region falls in the UV-B range.
Improved lifetime of microchannel-plate PMTs
2014
Abstract The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ≈ 6 C / cm 2 integrated anode charge without a substa…
The COMPASS RICH-1 fast photon detection system
2008
Abstract A fast photon detection system has been built as a part of the upgrade of the COMPASS RICH-1 detector: it is based on 576 multi-anode photomultiplier tubes (MAPMTs) coupled to individual fused silica lens telescopes and fast readout electronics. This system has replaced the MWPCs with CsI photo-cathodes in the central region ( 1.3 m 2 , 25% of the total area) of the COMPASS RICH-1 photon detectors and has successfully been operated during the data taking in 2006 and 2007. We report about the fast photon detection system design, construction and commissioning, in particular about the design optimization and the validation tests of the lens telescopes. Preliminary values for the incr…
Gain stabilization and noise minimization for SiPMs at cryogenic temperatures
2018
Abstract The performance of solid-state photon detectors such as avalanche photodiodes or silicon photomultipliers (SiPMs) is strongly affected by temperature. Important device characteristics for the detection of low light levels or single photons are photon detection efficiency, dark noise, and gain. In the present work the C-series SiPMs from SensL was characterized in cryogenic environments. At 77 K the SiPMs proved to be an excellent choice for single photon detection and an operation point with minimum noise contributions was found. At 4 K the performance was degraded, exhibiting a smaller gain and a larger noise.
Recent progress with microchannel-plate PMTs
2020
Abstract Microchannel-plate (MCP) PMTs were identified as the only suitable photon sensors for the two DIRC detectors of the PANDA experiment at FAIR. As the long-standing aging problem of MCP-PMTs was recently overcome by coating the MCP pores with an atomic layer deposition (ALD) technique, further improved 2 ″ MCP-PMTs were investigated. The best PHOTONIS device has reached a lifetime of > 20 C/cm2 integrated anode charge without any sign of aging. Also the newly developed 2 ″ MCP-PMTs of Hamamatsu are maturing and are usable in high rate environments. The status of our long-term lifetime measurements and the performance parameters of the currently most advanced ALD-coated MCP-PMTs from …