Automated wire tension measurement system for LHCb muon chambers Ciambrone, P.; Dané, E.; Dumps, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
06/2005, Letnik:
545, Številka:
1
Journal Article
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A wire tension meter has been developed for the multi-wire proportional chambers of the LHCb muon detector. The wire tension is deduced from its mechanical resonance frequency. In the LHCb muon ...chambers, the wires are 2
mm apart and electrically connected in groups of 3–32, so that the wire excitation system must be precisely positioned with respect to the wire to be tested. This wire is forced to oscillate by a periodic high voltage applied between that wire and a non-oscillating “sense wire” placed parallel and close to it. This oscillation produces a variation of the capacitance between these two wires which is measured by a high precision digital electronic circuit. At the resonance frequency this capacitance variation is maximum. The system has been systematically investigated and its parameters were optimized. In the range 0.4–1
N a good agreement is found between the mechanical tension measured by this system and by a dynamometer.
The KLOE2 experiment is operating at the Dafnee e- collider, designed to reach an instantaneous luminosity of 2*10^{\mathbf {32}} \mathbf {cm} ^{\mathbf {-2}} \mathbf {s} ^{\mathbf {-1}} at the \Phi ...resonance. Secondary vertex displacement are of paramount importance for the measurement of the CP violation in the kaon system. The most relevant detector to identify and reconstrut particles in the final state is the Drift Chamber. After 20 years of operation the front-end electronics of the detector is obsolete. Moreover the drift chamber electronics is based on an ASIC production line which was discontinued. New TDCs (Time to Digital Converter) have to be built whose architecture is based on the newest FPGAs present on the market. In this paper we describe the architecture, the performance of the new TDCs and their FPGA based front-end data acquistition. The new electronics has already been installed in the experiment.
Based on an integrated luminosity of 1.61 fb(-1)e(+)e(-) collision data collected with the KLOE detector at DA Phi NE, the Frascati phi -factory, a search for the P- and CP-violating decay eta -> ...pi (+)pi (-) has been performed. Radiative phi -> eta gamma decay is exploited to access the eta mesons. No signal is observed in the pi (+)pi (-) invariant mass spectrum, and the upper limit on the branching fraction at 90% confidence level is determined to be B(eta -> pi (+)pi (-)) < 4.9 x 10(-6), which is approximately three times smaller than the previous KLOE result. From the combination of these two measurements we get B(<eta> -> pi (+)pi (-)) < 4.4 x 10(-6) at 90% confidence level.
We searched for evidence of a Higgsstrahlung process in a secluded sector, leading to a final state with a dark photon U and a dark Higgs boson h′, with the KLOE detector at DAΦNE. We investigated ...the case of h′ lighter than U, with U decaying into a muon pair and h′ producing a missing energy signature. We found no evidence of the process and set upper limits to its parameters in the range 2mμ<mU<1000 MeV, mh′<mU.
We have measured the cross section σ(e+e−→π+π−γ) at an energy W=mϕ=1.02 GeV with the KLOE detector at the electron–positron collider DAΦNE. From the dependence of the cross section on the invariant ...mass of the two-pion system, we extract σ(e+e−→π+π−) for the mass range 0.35<s<0.95 GeV2. From this result, we calculate the pion form factor and the hadronic contribution to the muon anomaly, aμ.
We have measured the ratio Rϕ=BR(ϕ→η′γ)/BR(ϕ→ηγ) by looking for the radiative decays ϕ→η′γ and ϕ→ηγ into the final states π+π−7γ and 7γ, respectively, in a sample of ∼1.4×109ϕ mesons produced at the ...Frascati ϕ factory. We obtain Rϕ=(4.77±0.09stat±0.19syst)×10−3, from which we derive BR(ϕ→η′γ)=(6.20±0.11stat±0.25syst)×10−5. Assuming the η′ has zero gluonium content, we extract the pseudoscalar mixing angle in the quark-flavor basis, φP=(41.4±0.3stat±0.7syst±0.6th)°. Combining the value of Rϕ with other constraints, we estimate the fractional gluonium content of the η′ to be Z2=0.14±0.04 and the mixing angle to be φP=(39.7±0.7)°.
The ratio Rη=Γ(η→π+π−γ)/Γ(η→π+π−π0) has been measured by analysing 22 million ϕ→ηγ decays collected by the KLOE experiment at DAΦNE, corresponding to an integrated luminosity of 558 pb−1. The η→π+π−γ ...proceeds both via the ρ resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, Rη=0.1856±0.0005stat±0.0028syst, points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the η→π+π−γ decay could be described in a model-independent approach in terms of a single free parameter, α. The determined value of the parameter α is α=(1.32±0.08stat−0.09syst+0.10±0.02theo) GeV−2.
GASTONE64 (Gem Amplifier Shaper Tracking ON Events) is a novel 64-channel mixed analog-digital ASIC developed to readout the cylindrical GEM inner tracking detector of the KLOE-2 apparatus at the ...e+e−DAΦNE collider. It has been designed in the CMOS 0.35μm technology and each analog channel is made of preamplifier, shaper and discriminator. The expected input charge ranges between few fC up to 40fC, the charge sensitivity is 16mV/fC while the equivalent input noise charge (ENC) is 800e−+40e−/pF. The discriminated signals are read-out using a 100MBit/s LVDS serial data link. The power consumption is about 6mW/channel.
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