Dark Noise Rate Research Articles

Supernova Neutrino Detection with IceCube

IceCube was completed in December 2010. It forms a lattice of 5160 photomultiplier tubes that monitor a volume of ∼ 1 km3 in the deep Antarctic ice for particle induced photons. The telescope was designed to detect neutrinos with energies greater than 100 GeV. Owing to subfreezing ice temperatures, the photomultiplier dark noise rates are particularly low. Hence IceCube can also detect large numbers of MeV neutrinos by observing a collective rise in all photomultiplier rates on top of the dark noise. With 2 ms timing resolution, IceCube can track subtle features in the temporal development of the supernova neutrino burst. For a supernova at the galactic center, its sensitivity matches that of a background-free megaton-scale supernova search experiment. The sensitivity decreases to 20 standard deviations at the galactic edge (30 kpc) and 6 standard deviations at the Large Magellanic Cloud (50 kpc). IceCube is sending triggers from potential supernovae to the Supernova Early Warning System. The sensitivity to neutrino properties such as the neutrino hierarchy is discussed and simulations of tantalizing signatures, such as the formation of a quark star or a black hole as well as the characteristics of shock waves are presented. All results are preliminary.

Mass characterization of multi-pixel photon counters for the T2K 280 m near detector

A few thousands multi-pixel photon counters (MPPC) have been characterized for the T2K 280 m near detector (ND280). For this purpose a test facility has been developed enabling the characterization of 128 MPPC per day. A mean gain value of 5.4×10 5 at breakdown voltage ( V break)+1 V with a dispersion of 2.6% has been measured at 20 °C. It is shown that the accuracy of the test facility for the gain measurement is at the level of 0.76%. At 20 °C the dark noise rates (DNR) have been measured in a range from ∼400 up to ∼730 kHz at V break+1.6 V.

Studies on multiplication effect of noises of PPDs, and a proposal of a new structure to improve the performance

Pixelated Photon Detectors (PPDs) are arrayed APDs operated in Geiger-mode. Multi-Pixel Photon Counter (MPPC) is a PPD produced by Hamamatsu Photonics K.K. Test of dark noise rate of a 1600 pixel MPPC as a function of over-voltage at room temperature indicates that the over-voltage is limited up to a few volts because of explosive increase of noise rate. The over-voltage dependence of random noise rate is nevertheless mostly linear. We confirmed this is due to multiplication effect of noises because of after-pulsing and crosstalk. Over-voltage dependence of random noise and photon detection efficiency are qualitatively different. Considering the electric field structure of MPPC (p-on-n type) and Geiger-efficiency as a function of the position of initial pair creation, these characteristics are possible to be understood. One suggestion for p-on-n type PPD from these results is narrowing the depletion layer below the multiplication layer to reduce random noise and after-pulsing. Another proposal is to put additional buffer capacitance parallel to the diode to accomplish higher gain with lower over-voltage simultaneously with lower noise rate.

Silicon Photomultiplier Technology at STMicroelectronics

In this paper we present the results of the first electrical and optical characterization performed on 1 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> total area Silicon Photomultipliers (SiPM) fabricated in standard silicon planar technology at the STMicroelectronics Catania R&D clean room facility. The device consists of 289 microcells and has a geometrical fill factor of 48%. Breakdown voltage, gain, dark noise rate, crosstalk, photon detection efficiency and linearity have been measured in our laboratories. The optical characterization has been performed by varying the temperature applied to the device. The results shown in the manuscript demonstrate that the device already exhibits relevant features in terms of low dark noise rate and inter-pixel crosstalk probability, high photon detection efficiency, good linearity and single photoelectron resolution. These characteristics can be considered really promising in view of the final application of the photodetector in the Positron Emission Tomography (PET).

Development and study of the multi pixel photon counter

The Multi Pixel Photon Counter is a novel semiconductor photon sensor which consists of 100–1600 micro APD pixels. Each pixel works in limited Geiger mode with an inverse bias voltage around 80 V. The MPPC has many remarkable features such as high gain, large photon detection efficiency, low cost and tolerance for magnetic field. Fundamental properties, such as the gain, dark noise rate and inter-pixel cross-talk, have been measured with three different samples which have 100, 400, and 1600 pixels. Variation of the gain over 750 samples, and uniformity of the gain and photon sensitivity within one pixel are also evaluated. As the result of the tests, it is confirmed that the MPPC has satisfactory performance for many applications, not only for high energy physics experiments but also for medical engineering systems.

Large dynamic range photon detector with a temperature-stabilized Si-based multi-pixel photon counter

We present an efficient fluorescence detector in the visible region of the spectrum with a photon detection dynamic range over 10 (6) photons/s made of a temperature-stabilized Si-based multi-pixel photon counter at temperature down to 5 degrees C. We show that effective cooling of the device by means of a compact thermo-electric cooler brings several advantages, such as high gain, low dark noise rate, and thus high signal-to-noise ratio in the efficient fluorescence detection at 398.9 nm from the (1)S(0) ? (1)P(1) transition of the ytterbium atoms in an effusive atomic beam. We present also a comparison of the fluorescence detection efficiencies between the device and a side-on photo-multiplier tube with known gain positioned at the symmetric location from the ytterbium atomic beam.

Temperature dependent performance of ATLAS RPC

We investigated the behavior of ATLAS RPC counters in a temperature range from about 20 °C to about 30 °C. The counter gas volumes are made of low resistivity (from 1 ÷ 4 ⋅ 10 10 Ω ⋅ cm ) phenolic-melaminic polymers with linseed oil inner surface treatment and polycarbonate spacer. The measurements show that the counter properties related to the gas amplification (such as efficiency and cluster size) scale simply with temperature, but the counter properties related to the inner surface quality (such as dark current and noise rate) increase sensibly faster.

Performance of second generation BABAR resistive plate chambers

The BABAR detector has operated nearly 200 Resistive Plate Chambers (RPCs), constructed as part of an upgrade of the forward endcap muon detector, for the past two years. The RPCs experience widely different background and luminosity-driven singles rates (0.01–10 Hz/cm 2) depending on position within the endcap. Some regions have integrated over 0.3 C/cm 2. RPC efficiency measured with cosmic rays is high and stable. The average efficiency measured with beam is also high. However, a few of the highest rate RPCs have suffered efficiency losses of 5–15%. Although constructed with improved techniques and minimal use of linseed oil, many of the RPCs, which are operated in streamer mode, have shown increased dark currents and noise rates that are correlated with the direction of the gas flow and the integrated current. Studies of the above aging effects are presented and correlated with detector operating conditions.