Search results for "silicon"
showing 10 items of 1391 documents
Lifetimes of charged and neutralD mesons
1987
We have measured the lifetimes of hadronically produced charged and neutralD mesons using silicon microstrip detectors and an active silicon target in the NA32 spectrometer at the CERN SPS. We obtainτD± = (10.9±1.51.9)·10−13s andτD(−)10 = (4.2±0.5)·10−13s based on 59 and 90 fully reconstructed decays respectively, giving a ratioτD±/τD(−)10 of 2.6 ±0.5.
Measurement of the masses and lifetimes of the charmed mesonsD 0,D + andD s +
1990
We present the final results on the measurement of the masses and lifetimes of the mesonsD0,D+ andD s + in the NA32 experiment at the CERN SPS, using silicon microstrip detectors and charge-coupled devices for vertex reconstruction. We measure the following lifetimes:\(\tau _{D^0 } = 3.88 \pm _{0.21}^{0.23} \cdot 10^{ - 13} s\) using a sample of 479D°→K−π+π−π+ and 162D°→K−π+ decays;\(\tau _{D^ + } = 10.5 \pm _{0.72}^{0.77} \cdot 10^{ - 13} s\) with a sample of 317D+→K−π+π+ decays;\(\tau _{D_s^ + } = 4.69 \pm _{0.86}^{1.02} \cdot 10^{ - 13} s\) with a sample of 54D s + →K+K−π+ decays. We measure the following masses:mD0=1864.6±0.3±1.0 MeV,mD+=1870.0±0.5±1.0 MeV and\(m_{D_s^ + } \)=1967.0±1.0…
Production properties ofD 0,D +,D *+ andD s + in 230 GeV/c? ? andK ?-Cu interactions
1991
We have studied the hadronic production of charmed mesons in the NA 32 experiment at CERN. A special trigger together with a high resolution vertex detector consisting of charge coupled devices and silicon microstrip detectors allowed the selection of very clean samples of charmed mesons. We have collected 852 fully reconstructed decays: 60D + →K + K −π+, 543D°→K −π+ andK −π+π−π+ as well as 249D +→K −π+π+ (or charge conjugate). 147 mesons out of our $${{D^0 } \mathord{\left/ {\vphantom {{D^0 } {\bar D^0 }}} \right. \kern-\nulldelimiterspace} {\bar D^0 }}$$ sample were produced via chargedD * state. For all charmed mesons we determine the total production cross-section and study thex F andp …
g Factor of Lithiumlike Silicon: New Challenge to Bound-State QED
2019
The recently established agreement between experiment and theory for the $g$ factors of lithiumlike silicon and calcium ions manifests the most stringent test of the many-electron bound-state quantum electrodynamics (QED) effects in the presence of a magnetic field. In this Letter, we present a significant simultaneous improvement of both theoretical $g_\text{th} = 2.000\,889\,894\,4\,(34)$ and experimental $g_\text{exp} = 2.000\,889\,888\,45\,(14)$ values of the $g$ factor of lithiumlike silicon $^{28}$Si$^{11+}$. The theoretical precision now is limited by the many-electron two-loop contributions of the bound-state QED. The experimental value is accurate enough to test these contributions…
Comparison of Silicon Photomultiplier Characteristics using Automated Test Setups
2016
Silicon Photomultipliers (SiPM) are photo-sensors consisting of an array of hundreds to thousands pixels with a typical pitch of 10-100 μm. They exhibit an excellent photon counting and time resolution. Therefore applications of SiPMs are emerging in many fields. In order to characterize SiPMs, the PRISMA Detector Lab at Mainz has established three automated test setups. Setup-A is dedicated to measure the gain, the dark count rate and the optical crosstalk probability. The temperature dependencies are characterized by operating the setup in a climate chamber. Setup-B is an optical system to measure the photon detection efficiency. Setup-C addresses the most challenging aspect of comparing …
Proof-of-principle measurements with a liquid-scintillator detector using wavelength-shifting optical modules
2018
Based on test-beam measurements, we study the response of a liquid-scintillator detector equipped with wavelength-shifting optical modules, that are proposed e.g. for the IceCube experiment and the SHiP experiment, and adiabatic light guides that are viewed either by a photomultiplier tube or by an array of silicon photomultipliers. We report on the efficiency, the time resolution and the detector response to different particle types and point out potential ways to improve the detector performance.
A tracking fiber detector based on silicon photomultipliers for the KAOS spectrometer
2011
A tracking detector based on two meters long scintillating fibers read out by silicon photomultipliers (SiPM) is being developed for the Kaos spectrometer at the Mainz Microtron MAMI. Results from a prototype setup using 2 mm square fibers and large area SiPM readout are presented. The detection efficiency of such a combination was measured to be between 83 and 100% depending on the threshold on the SiPM amplitude. A Monte Carlo simulation based on a physical model was employed in order to extract the photon detection efficiency of the SiPM devices.
SNR measurements of silicon photomultipliers in the continuous wave regime
2014
We report on our Signal-to-Noise Ratio (SNR) measurements carried out, in the continuous wave regime, at different frequencies and at various temperatures, on a novel class of silicon photomultipliers (SiPMs) fabricated in planar technology on silicon p-type substrate. SNR of SiPMs is given by the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square (RMS) deviation of the same current. In our measurements, we have employed a 10 Hz equivalent noise bandwidth, around the lock-in amplifier reference frequency. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current, while background light …
Precise determination of the 1s Lamb Shift in hydrogen-like heavy ions at the ESR storage ring using microcalorimeters
2015
The precise determination of the energy of the Lyman α1 and α2 lines in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. To improve the precision of such experiments, the new detector concept of microcalorimeters, which detect the temperature change of an absorber after an incoming particle or photon has deposited its energy as heat, is now exploited. The microcalorimeters for x-rays used in these experiments consist of arrays of silicon thermometers and x-ray absorbers made of high-Z material. With such detectors, a relative energy resolution of about 1 per mille is obtained in the energy regime of 50–100 keV. Two successful measu…
Comparison between transmission and scattering spectrum reconstruction methods based on EPID images.
2013
Numerous improved physics-based methods for Linac photon spectra reconstruction have been published; some of them are based on transmission data analysis and others on scattering data. In this work, the two spectrum unfolding approaches are compared in order to experimentally validate its robustness and to determine which is the optimal methodology for application on a clinical quality assurance routine. Both studied methods are based on EPID images generated when the incident photon beam impinges onto plastic blocks. The distribution of transmitted/scatter radiation produced by this object centered at the beam field size was measured. Measurements were performed using a 6 MeV photon beam p…