2,247 research outputs found
A linear optical coupler for cryogenic detectors
Abstract We present an improved version of a linear low-noise optical coupler having differential input and capable of driving a twisted cable to long distances, avoiding ground loops and electromagnetic interference. Owing to device optimization, this circuit version is able to be fast. Its frequency bandwidth is about 900 kHz, more than ten times larger than our previous implementation. The optical coupler presented is therefore suitable to be used with most of the applications with cryogenic detectors
Characterization of the Hamamatsu R11265-103-M64 multi-anode photomultiplier tube
The aim of this paper is to fully characterize the new multi-anode
photomultiplier tube R11265-103-M64, produced by Hamamatsu. Its high effective
active area (77%), its pixel size, the low dark signal rate and the capability
to detect single photon signals make this tube suitable for an application in
high energy physics, such as for RICH detectors. Four tubes and two different
bias voltage dividers have been tested. The results of a standard
characterization of the gain and the anode uniformity, the dark signal rate,
the cross-talk and the device behaviour as a function of temperature have been
studied. The behaviour of the tube is studied in a longitudinal magnetic field
up to 100 Gauss. Shields made of a high permeability material are also
investigated. The deterioration of the device performance due to long time
operation at intense light exposure is studied. A quantitative analysis of the
variation of the gain and the dark signals rate due to the aging is described.Comment: 22 page
Characterization of high impedance connecting links for Bolometric detectors
Abstract High impedance connecting links and cables are tested at low frequency in terms of their parasitic impedance to ground and to neighboring connecting links. These parameters must be well characterized with detectors operated at low temperature, especially when the very front-end is at room temperature, which results in a long link. This is the case of the LUCIFER experiment, an array of crystals where every event of interest produces two signals, one composed of phonons, the other of photons. The parasitic impedance is usually considered to be the parallel combination of a resistance and a capacitance. We characterized both and found that from the static measurements the capacitance of the cable resulted much larger. On the basis of this result we optimized the measurement set-up and developed a model to account for this behavior
GEO COLLECTOR BOT: A TELEGRAM-BASED OPEN TOOLKIT TO SUPPORT FIELD DATA COLLECTION
Georeferenced field data collection has become a popular practice allowing everyone to contribute to mapping objects or reporting events. The spread of mobile devices - capable of recording and sharing location coordinates, media and features while on the go - is primarily accountable for such diffusion. Accordingly, a number of mobile apps and software frameworks have been developed and released to perform field data collection. These frameworks allow to customize and dispatch collection forms as well as to manage contributors and records through web interfaces or database management systems. From the contributors’ perspective, specific mobile client apps need to be installed to access selectively the collection forms and contribute to the data collection on the field using their mobile devices. This operation might inhibit the sporadic contribution of occasional users who may not be willing to install additional software. To overcome this limitation, this work presents the Geo Collector Bot, an alternative software toolkit to empower field data collection projects avoiding the development and/or the installation of a specific mobile app on contributors’ devices. The Geo Collector Bot is a configurable Telegram-based chatbot enabling to dispatch of data collection forms that can be activated and filled in through Telegram chats. The ultimate goal of the presented work is to provide an alternative free and open-source software framework suitable for general-purpose field data collection applications. Development patterns and system architecture are described in detail alongside future improvements and outlooks for the Geo Collector Bot project
Cryogenic light detectors with enhanced performance for rare events physics
We have developed and tested a new way of coupling bolometric light detectors
to scintillating crystal bolometers based upon simply resting the light
detector on the crystal surface, held in position only by gravity. This
straightforward mounting results in three important improvements: (1) it
decreases the amount of non-active materials needed to assemble the detector,
(2) it substantially increases the light collection efficiency by minimizing
the light losses induced by the mounting structure, and (3) it enhances the
thermal signal induced in the light detector thanks to the extremely weak
thermal link to the thermal bath. We tested this new technique with a 16 cm
Ge light detector with thermistor readout sitting on the surface of a large
TeO bolometer. The light collection efficiency was increased by greater
than 50\% compared to previously tested alternative mountings. We obtained a
baseline energy resolution on the light detector of 20~eV RMS that, together
with increased light collection, enabled us to obtain the best vs
discrimination ever obtained with massive TeO crystals. At
the same time we achieved rise and decay times of 0.8 and 1.6 ms, respectively.
This superb performance meets all of the requirements for the CUPID (CUORE
Upgrade with Particle IDentification) experiment, which is a 1-ton
scintillating bolometer follow up to CUORE.Comment: 6 pages, 4 figure
An ultra fast, low power readout chain for single photon sensitivity with multi-anode photomultiplier tubes for the RICH upgrade at LHCb
Abstract An upgrade proposal for the LHCb RICH detectors at the Large Hadron Collider at CERN is being developed at the INFN section of Milano Bicocca, based on multi-anode photomultiplier tubes. The application requires the fast readout of Cherenkov rings of photons, with single photon sensitivity, at an event rate up to 40 MHz. The proposed readout chain is tailored for the R7600 multi-anode photomultiplier tubes from Hamamatsu, which proved to fit the single photon sensitivity requirement. The readout electronics for each pixel will be composed of an analog pulse shaper, a binary discriminator and additional digital circuitry to count the pulses. A prototype of the analog shaper was built with commercial discrete transistors in Silicon–Germanium (SiGe) Heterojunction technology. The tradeoff between response speed and power dissipation was investigated; and power as low as a few mW per channel could be achieved with response times of the order of one nanosecond. Furthermore, noise and jitter were evaluated, showing very good performances of the prototype
Electrical characterization of the low background Cu-PEN links of the CUORE experiment
Abstract In the CUORE experiment, under construction at LNGS (Gran Sasso National Laboratory), Cu-PEN tapes are the first part of the connecting links between the detector and the front-end electronics. Deep electrical characterization on each tape is to be performed, to ascertain that they comply with the requirements of the experiment. The characterization method is presented here. The first part is based on the time domain reflectometry (TDR) technique, to check the integrity of the electrical link while touching only one end of the tape, to avoid any possible damage to the bonding pads. The TDR measurement allows to locate possible defects on the tapes with a resolution of about 5 cm. The second part of the characterization is focused on the parasitic impedance between neighboring links. For this characterization, a commercial electrometer is used; custom boards with remote control capability were built, in order to be able to check the links in vacuum and reach sensitivities on the parasitic conductance of the order of 1 pA/V
Spatial and temporal characterization of a Bessel beam produced using a conical mirror
We experimentally analyze a Bessel beam produced with a conical mirror,
paying particular attention to its superluminal and diffraction-free
properties. We spatially characterized the beam in the radial and on-axis
dimensions, and verified that the central peak does not spread over a
propagation distance of 73 cm. In addition, we measured the superluminal phase
and group velocities of the beam in free space. Both spatial and temporal
measurements show good agreement with the theoretical predictions.Comment: 5 pages, 6 figure
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