A new method for the measurement of loss factor for an rf cavity is presented. The method consists of measuring the above quantity by means of the detection of both the rf voltage induced by an ...electron bunch in the device under test and the bunch charge. The device to be investigated is a copper reentrant T-shaped cavity. The experimental results and their comparison with analytical and numerical results are presented.
Antihydrogen production and precision experiments Holzscheiter, M.H.; Bendiscioli, G.; Bertin, A. ...
Nuclear physics. Section B, Proceedings supplement,
06/1997, Letnik:
56, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The study of CPT invariance with the highest achievable precision in all particle sectors is of fundamental importance for physics. Equally important is the question of the gravitational acceleration ...of antimatter. In recent years, impressive progress has been achieved in capturing antiprotons in specially designed Penning traps, in cooling them to energies of a few milli-electron volts, and in storing them for hours in a small volume of space. Positrons have been accumulated in large numbers in similar traps, and low energy positron or positronium beams have been generated. Finally, steady progress has been made in trapping and cooling neutral atoms. Thus the ingredients to form antihydrogen at rest are at hand. Once antihydrogen atoms have been captured at low energy, spectroscopic methods can be applied to interrogate their atomic structure with extremely high precision and compare it to its normal matter counterpart, the hydrogen atom. Especially the 1S–2S transition, with a lifetime of the excited state of 122 msec and thereby a natural linewidth of 5 parts in 10
16, offers in principle the possibility to directly compare matter and antimatter properties at a level of 1 part in 10
18.
In this paper are presented the results of Monte Carlo simulations on the capability of the proposed NEMO-km
3 telescope to detect TeV muon neutrinos from Galactic microquasars. For each known ...microquasar we compute the number of detectable events, together with the atmospheric neutrino and muon background events. We also discuss the detector sensitivity to neutrino fluxes expected from known microquasars, optimizing the event selection also to reject the background; the number of events surviving the event selection are given. The best candidates are the steady microquasars SS433 and GX339-4 for which we estimate a sensitivity of about 5
×
10
−11
erg/cm
2
s; the predicted fluxes are expected to be well above this sensitivity. For bursting microquasars the most interesting candidates are Cygnus X-3, GRO J1655-40 and XTE J1118+480: their analyses are more complicated because of the stochastic nature of the bursts.
A storage ring for crystalline beam studies Tecchio, L; Bisoffi, G; Ciullo, G ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1997, Letnik:
391, Številka:
1
Journal Article
Recenzirano
The possibility of generating crystallized ion beams, i.e. beams whose particles are located at fixed positions, has always excited the interest of most people working on particle accelerators. The ...reason of this interest has many aspects: knowledge either of a completely new research field or of some of the applicative potentialities, connected with crystalline beams, would justify a careful investigation of this subject.
After the successful exploitation of electron cooling in several heavy ion storage rings the possibility of generating crystalline ion beams became more realistic. New cooling methods, like laser cooling, give a further opportunity to reach an ultracold system of particles necessary for the state transition to the crystalline configuration.
The conceptual design of a low-energy heavy-ion storage ring, called CRYSTAL, proposed for the experimental demonstration of crystalline beams at Legnaro Laboratories is presented. The physics of crystalline beams as well as the main criteria to design a storage ring suitable to crystallize ion beams are discussed. The effects of instabilities for space charge dominated beams, shear forces in dipole magnets and lattice periodicity breaking are also discussed in detail.
Data acquisition electronics for NESTOR experiment: project and tests Ameli, Fabrizio; Bonori, Maurizio; Bottai, Sergio ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/1999, Letnik:
423, Številka:
1
Journal Article
Recenzirano
The NESTOR detector, at present under construction, is a telescope for high-energy neutrino astronomy. The apparatus, based on Cherenkov light detection, will be deployed in deep sea (about 4000
m) ...near the S.W. Greek coast. We briefly describe the NESTOR detector, then we describe with more details the electronics for NESTOR data acquisition and transmission. The detector signals are sampled at 200
MHz and all the resulting information are transmitted to the laboratory on 30
km long electro-optical cable. The estimated Mean Time Between Failure of the full electronics system is greater than 20 years. Tests performed on the first prototypes confirm the main characteristics of these electronics: the dynamic range allowed for the signals is bigger than 1000, the pulse shape is reconstructed with an 8 bit ADC accuracy and the resolution in the measurement of the signal “threshold crossing time” is better than 200
ps.
In a recent investigation, we studied two-dimensional point-defected photonic bandgap cavities composed of dielectric rods arranged according to various representative periodic and aperiodic ...lattices, with special emphasis on possible applications to particle acceleration (along the longitudinal axis). In this paper, we present a new study aimed at highlighting the possible advantages of using hybrid structures based on the above dielectric configurations, but featuring metallic rods in the outermost regions, for the design of extremely-high quality factor, bandgap-based, accelerating resonators. In this framework, we consider diverse configurations, with different (periodic and aperiodic) lattice geometries, sizes, and dielectric/metal fractions. Moreover, we also explore possible improvements attainable via the use of superconducting plates to confine the electromagnetic field in the longitudinal direction. Results from our comparative studies, based on numerical full-wave simulations backed by experimental validations (at room and cryogenic temperatures) in the microwave region, identify the candidate parametric configurations capable of yielding the highest quality factor.
In this Letter, we present a study of the confinement properties of point-defect resonators in finite-size photonic-bandgap structures composed of aperiodic arrangements of dielectric rods, with ...special emphasis on their use for the design of cavities for particle accelerators. Specifically, for representative geometries, we study the properties of the fundamental mode (as a function of the filling fraction, structure size, and losses) via 2-D and 3-D full-wave numerical simulations, as well as microwave measurements at room temperature. Results indicate that, for reduced-size structures, aperiodic geometries exhibit superior confinement properties by comparison with periodic ones.
The timing calibration is a delicate operation to perform for assuring the full functionality of a large underwater neutrino telescope. In this paper we illustrate the main features of our system for ...timing calibration tailored to the needs of the prototype of the NEMO (NEutrino Mediterranean Observatory) apparatus. We point out that the approach proposed can be easily adapted to work in any underwater neutrino telescope.
PDF
