[en] The inertial confinement fusion (ICF) community must become more cognizant of the neutron-induced background levels in charge-coupled device (CCD) detectors that are replacing film as the recording medium in many ICF diagnostics. This background degrades the signal-to-noise ratio (SNR) of the recorded signals and for the highest-yield shots comprises a substantial fraction of the pixel's full well capacity. CCD detectors located anywhere in the OMEGA Target Bay are precluded from recording high precision signals (SNR>30) for deuterium--tritium neutron yields greater than 10¹³. CCDs make excellent calibrated neutron detectors. The average CCD background level is proportional to the neutron yield, and we have measured a linear response over four decades. The spectrum of deposited energy per pixel is heavily weighted to low energies, <50 keV, with a few isolated saturated pixels. Most of the background recorded by the CCDs is due to secondary radiation produced by interactions of the primary neutrons with all the materials in the Target Bay as well as the shield walls and the floor. Since the noise source comes from all directions it is very difficult to shield. The fallback position of using film instead of CCD cameras for high-neutron-yield target shots is flawed, as we have observed substantially increased fog levels on our x-ray recording film as a function of the neutron yield

[en] We present an overview of spectrally resolved electromagnetic emission from laser plasmas produced by irradiating solid targets at 351 nm and 1053 nm. The spectra are indicative of a large number of parametric processes occurring in the corona between 0.05n/sub c/ and n/sub c/. The data were taken in support of laser fusion experiments carried out at the Laboratory for Laser Energetics

[en] A 51 MHz, 200 KV, aluminum cavity, in vacuum, has been built, tested and set in operation on the Frascati storage ring. Problems encountered in building, vacuum sealing and conditioning are illustrated. Behaviour on the accelerator is also mentioned

[en] The resonator kicker magnet and its full-scale aluminium prototype were developed for the DAFNE bunch-by-bunch feedback system, based on six waveguides. According to the modeling and measurement data its maximum complete resistance equals 750 Ohm and the frequency range - 220 MHz. Apart from this damping waveguides strongly decrease the cross-sectional and longitudinal impedances. No tuning and cooling are required due to wide frequency band and low internal scattering

[en] A program of construction of test superconducting linac with low emittance, high peak current and low energy dispersion is in course at Frascati INFN laboratories. This program is motivated by the consideration that RF superconductivity is very promising in the effort to achieve the break through in ideas and techniques that seems necessary to implement new very high energy accelerators. The linear superconducting accelerator test complex consists of : 1) 1 MeV injector at normal temperature; 2) 4 multicell superconducting cavities with an overall 4.8 m useful accelerating length; 3) recirculation channel; and 4) refrigeration and power plants. The accelerator will deliver a beam of energy between 25(49) and 36(73) MeV depending on the maximum gradient achieved in the cavities. The machine is to be assembled within two years from the date of emission of the first order. 5 references, 1 figure, and 2 tables

No abstract available

[en] The injection system, for the Frascati Φ-factory DAΦNE, is designed to store ∼10¹³ positrons and electrons in the two main rings in an overall injection time at startup of ∼10 minutes. The system will consist of a high current electron Linac (E ∼ 250 MeV), a low current high energy electron-positron section (E > 510 MeV) and a compact damping ring in order, to avoid injection saturation, to increase longitudinal acceptance and to decouple the design of the main rings from injection requirements. The two Linac sections will provide ∼ 0.3 nC of positrons within ± 1% energy spread in 10 ns pulses for injection at 50 Hz into a single 76 MHz bucket of the damping ring. Extraction of the high quality damped bunch from the accumulator will take place at 1 Hz, filling one main ring bucket at a time. The Linac design foresees 3 m long 2π/3 TW constant gradient accelerating sections with SLED systems in order to increase the energy gain. The magnetic structure of the damping ring is designed to be accommodated in a 12 x 12 m² hall, and it is made of four quasi-achromatic bending sections and four long straights to accommodate injection and extraction pulsed elements and the RF system

[en] Multibunch operation in high current storage rings like DAΦNE can be seriously limited by coupled bunch oscillations driven by resonant e.m. fields trapped somewhere along the vacuum chamber. The design of each vacuum chamber component aims to keep the beam coupling impedance below the values for which multibunch instabilities can be controlled by feedback systems. The impedance of some of the most critical devices has been measured and a summary of the obtained results is presented. (author)

[en] The choice of a suitable geometry in designing a radio-frequency cavity for e⁺e^- storage ring allows the reduction of multipacting (MP) discharges. We have studied the behaviour of resonant electron discharges in the RF cavity of the Adone storage ring in Frascati, that shows a broad MP barrier in the 35 to 70 kV range of the accelerating voltage. It can be explained by one point MP on the end-plates of the resonator. Our computer simulations of the trajectories of electrons in the RF fields of the cavity clearly show multipacting trajectories in that region of the cavity at about that field level. On the base of our experimental measurements and simulations, the design of a new RF cavity, multipactor free in the end-plates region, is presented

[en] The choice of a suitable geometry in designing a radio-frequency cavity for e⁺e^- storage ring allows the reduction of multipacting (MP) discharges. The authors have studied the behavior of resonant electron discharges in the RF cavity of the Adone storage ring in Frascati, that shows a broad MP barrier in the 35 to 70 kV range of the accelerating voltage. It can be explained by one point MP on the end-plates of the resonator. Their computer simulations of the trajectories of electrons in the RF fields of the cavity clearly show multipacting trajectories in that region of the cavity at about that field level. On the base of their experimental measurements and simulations, the design of a new RF cavity, multipactor free in the end-plates region, is presented