The design of the MEG II experiment Baldini, A. M; Baracchini, E; Bemporad, C ...
The European physical journal. C, Particles and fields,
05/2018, Letnik:
78, Številka:
5
Journal Article
Recenzirano
Odprti dostop
The MEG experiment, designed to search for the Formula omitted decay, completed data-taking in 2013 reaching a sensitivity level of Formula omitted for the branching ratio. In order to increase the ...sensitivity reach of the experiment by an order of magnitude to the level of Formula omitted, a total upgrade, involving substantial changes to the experiment, has been undertaken, known as MEG II. We present both the motivation for the upgrade and a detailed overview of the design of the experiment and of the expected detector performance.
The tracking system for the IDEA detector at future lepton colliders Chiarello, G.; Corvaglia, A.; Grancagnolo, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
While most requirements for detectors at the International Linear Collider (ILC) are very similar to those for the future circular e+e−-colliders FCC–ee (e+e− Future Circular Collider at CERN) or ...CEPC (Circular Electron–Positron Collider at IHEP, China), the luminosity is expected to be one or two orders of magnitude larger, with a much shorter bunch spacing, placing severe constraints on the tracking system, favouring an intrinsically fast main tracker to fully exploit the cleanliness of the e+e− environment. Moreover, limits on the maximum magnetic field of the tracker solenoid represent a problem for a large volume TPC, because of the resolution degradation, and for a Si tracker, since it would require a larger radius. The proposed ultra-light He based Drift Chamber is 4m long, starting at a radius of ∼30cm and extending up to 2m, with ≲1.5cm drift cells, arranged in a fully stereo configuration ((50–250)mrad) and instrumented with readout electronics implementing the Cluster Counting/Timing technique. The total material budget is approximately 0.016X0 for tracks in the barrel region and 0.05X0 for forward tracks, providing a momentum resolution of ∼5×10−4 for <10GeV∕c and of <4×10−3 for 100GeV∕c tracks. Moreover, the use of the Cluster Counting technique will allow for a particle identification (PID) resolution <3%, a factor two better than the resolution attainable with dE/dx technique. We will illustrate the tracking system performance obtained with detailed simulations. The hardware features and the construction procedures of the proposed Drift Chamber, making use of the assembly technique developed for MEG2, will also be presented.
•Drift chamber proposal for the next generation of electron–positron accelerators.•Ultra-light helium based, fully stereo (no axial layers) drift chamber.•High spatial resolution obtained thanks to the cluster timing technique.•High particle identification capabilities thanks to the cluster counting technique.
A 10−3 drift velocity monitoring chamber for the MEG II experiment Cuna, F.; Chiarello, G.; Miccoli, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2023, Letnik:
1046
Journal Article
Recenzirano
The MEG-II experiment searches for the lepton-flavor-violating decay: μ⟶e+γ. The reconstruction of the positron trajectory uses a drift chamber operated with a mixture of He and iC4H10 gas. It is ...crucial to provide a stable performance of the detector in terms of its electron transport parameters, avalanche multiplication, composition and purity of the gas mixture. In order to have a continuous monitoring of the quality of the gas injected, we plan to install a small drift chamber, with a simple geometry that allows to measure very precisely the electron drift velocity in a prompt way. The chamber is a small box with cathode walls, that determine a highly uniform electric field inside two adjacent drift cells. Along the axis separating the two drift cells, four staggered sense wires alternated with five guard wires collect the drifting electrons. The trigger is provided by two 90Sr radioactive sources placed on top of a two thin scintillator tiles telescope. The whole system is designed to give a response in few minutes about drift velocity variations at the 10−3 level. In this paper the development of the drift chamber is presented, with a particular focus on the details of its construction.
The Central Tracker of the CMD3 detector Cuna, F.; Chiarello, G.; Miccoli, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2023, Letnik:
1045
Journal Article
Recenzirano
The CMD-3 experiment has been operating at the VEPP-2000 electron–positron collider, at the Budker Institute of Nuclear Physics, since December 2010. Its main goal is to measure the hadronic cross ...sections necessary to evaluate the anomalous magnetic moment of the muon. The discrepancy between the theoretical calculations and the experimental results obtained at the Brookhaven experiments is approximately 3.7 σ. The comparison between the results of the new “g-2” experiment at Fermilab and the theoretical calculation thanks to the new experimental contributions from CMD3 would provide important contributions to this measurement, which could prove the existence of New Physics. A key element for the success the CMD3 experiment is the tracking detector, which is a drift chamber built in the year 2009 at INFN of Lecce. Because of aging effects, its replacement is necessary. This paper presents the innovative design for the new ultralight CMD3 drift chamber.
•CMD3 experiment studies the anomalous magnetic moment of the muon.•The CMD3 new drift chamber is an ultralight multiwire drift chamber.•The goal is to maximize the transparency and minimize the multiple Coulomb scattering.•The mechanical design separates the gas containment from the wire support function.•The chamber will be equipped with cluster counting/timing readout techniques.
The central tracker of SCTF and CMD3 detectors Cuna, F.; Chiarello, G.; Miccoli, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2022, Letnik:
1040
Journal Article
Recenzirano
The CMD3 experiment has been operating at the VEPP-2000 electron-positron collider, at the Budker Institute of Nuclear Physics, since December 2010. Its main goal is to measure the hadronic cross ...sections necessary to evaluate the anomalous magnetic moment of the muon. The discrepancy between the theoretical calculations and the experimental results obtained at the Brookhaven experiments is approximately 3.7 σ.
The comparison between the results of the new “g-2” experiment at Fermilab and the theoretical calculation with the new experimental contributions from CMD3 could confirm the discrepancy, which is a new important hint of New Physics.
A key element for the success the CMD3 experiment is the tracking detector, which is a drift chamber built in the year 2009 at INFN of Lecce. Due to aging effects, its replacement is necessary, so that an innovative tracking detector, named TraPId (Tracking and Particle Identification), has been designed: an ultra-light drift chamber equipped with cluster counting/timing readout techniques, which exploits the expertise gained with the successful construction of the MEG II drift chamber. The drift chamber proposed for CMD3 will be also the prototype for the tracking system of the future Super Charm-Tau Factory detector (SCTF).
In this paper, the new design of TraPId is described, with a focus on the mechanical design of the end plates, their novel tension recovery scheme and the expected performances.
We propose a fast acquisition and elaboration system in order to process signals coming from Drift Chambers. The system is made of an analog Front End, designed in our laboratory for signal ...acquisition and a Demo Board by Texas Instruments for data elaboration. The Front End electronics is a multistage amplifier board based on high performance commercial devices. Texas Instruments board includes an Analog to Digital Converter and a FPGA (Field Programmable Gate Array) in order to implement algorithm for Cluster Counting and Timing purposes.
Ultra-low mass and high granularity Drift Chambers fulfill the requirements of tracking systems for modern High Energy Physics experiments at future high luminosity accelerators (FCC or CEPC). The ...application of the Cluster Counting/Timing (CCT) technique adds a valuable particle identification capabilities with resolutions outperforming the traditional dE/dx technique. By measuring the arrival times of each individual ionization electron to the sense wire and by using suitable statistical tools it is possible to perform a bias free estimate of the impact parameter and a precise particle identification in drift chamber operating in a Helium based gas mixtures. The CCT technique consisting in identifying pulses due to different ionization electrons and in associating them in clusters according to their relative time delays, therefore it is necessary to have read-out interfaces capable of processing such high speed signals. This requires a data acquisition chain, able to manage the low amplitude signals from the sense wires (a ∼few mV) with a high bandwidth (∼1 GHz). Requirements on the drift chamber performance impose analog-to-digital conversions by a fast ADC at sample rates of at least 2 GS/s with 14-bit resolution. These constraints, together with maximum drift times and many readout channels, impose some sizeable data reduction strategy, while preserving all relevant information. Measuring both the amplitude and the arrival time of each peak in the signal associated to each ionization electron is the minimum requirement on the data transfer for storage to prevent any data loss. An electronic board including a Fast ADC and an FPGA for real-time processing of drift chamber signals is presented. The implementation of different algorithms for peaks finding are compared.
•Development of a signal acquisition chain for a ultra-low mass drift chamber.•The application of the CCT adds a valuable particle identification capabilities..•The development of a CTT identifies the signal peaks and reconstructs the time of the single cluster.•Development of real time algorithms to acquire drift chamber signals.
IDEA (Innovative Detector for an Electron–positron Accelerator) is a general-purpose detector concept, designed to study electron–positron collisions in a wide energy range in a very large circular ...leptonic collider. Its drift chamber is designed to provide an efficient tracking, a high precision momentum measurement and an excellent particle identification by exploiting the application of the cluster counting technique. To investigate the potential of the cluster counting techniques on physics events, a simulation of the ionization cluster generation is needed, therefore we developed an algorithm which can use the energy deposit information provided by the Geant4 toolkit to reproduce, in a fast and convenient way, the cluster number and cluster size distributions. The results obtained confirm that the cluster counting technique allows to reach a resolution two times better than the traditional dE/dx method. A beam test has been performed during November 2021 at CERN on the H8 beam line to validate the simulations results, to define the limiting effects for a fully efficient cluster counting and to count the number of electron clusters released by an ionizing track at a fixed βγ as a function of the track angle. The simulation and the beam test results will be described briefly in this issue.
The ultra-low mass cylindrical drift chamber designed for the MEG II experiment is a challenging apparatus made of 1728 ϕ=20μm gold plated tungsten sense wires, 7680 ϕ=40μm and 2496 ϕ=50μm silver ...plated aluminium field wires. Because of electrostatic stability requirements all the wires have to be stretched at mechanical tensions of ∼25, ∼19 and ∼29g respectively which must be controlled at a level better than 0.5g. This chamber is presently in acquisition, but during its construction ∼100 field wires broke, because of chemical corrosion induced by the atmospheric humidity.
On the basis of the experience gained with this chamber we decided to build a new one, equipped with a different type of wires less sensitive to corrosion. The choice of the new wire required a deep inspection of its characteristics and one of the main tools for doing this is a system for measuring the wire tension by means of the resonant frequency technique, which is described in this paper. The system forces the wires to oscillate by applying a sinusoidal signal at a known frequency, and then measures the variation of the capacitance between a wire and a common ground plane as a function of the external signal frequency. We present the details of the measuring system and the results obtained by scanning the mechanical tensions of two samples of MEG II cylindrical drift chamber wires and discuss the possible improvements of the experimental apparatus and of the measuring technique.
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