[en] Mechanical and thermal impact of the plasma focus discharge on structural elements of diagnostic windows of the PFM-72m discharge installation are calculated. The absence of critical impact at early discharge stages and during the first 300 ns after the “plasma focus” formation is shown. The possibility of shock impact on the surface of diagnostic windows at later times, which may result in their substantial deformation and destruction, is demonstrated.

[en] The theoretical and numerical steady-state calculation of the width of an escaping plasma stream through a magnetic mirror solves the self-consistent potential and charge distribution for a low beta plasma. The leak widths is obtained as the geometric mean of the ion and electron Larmor radius, also called hybrid width, in agreement with some experimental measurements. If the out-streaming plasma is unstable or collisional, the leak width can only larger, contrary to earlier results in the literature. (orig.)

[en] In lightly beam loaded superconducting accelerators the rf power requirements are dictated by the maximum amount of microphonics that the system must be able to control and by the energy content of the cavity. In previous machines, such as heavy-ion boosters, the energy content of the cavities was relatively small and one could afford to specify a large control window and still use low power (∼100 W) rf sources. In newer accelerators that are being contemplated--such as the CEBAF 12 GeV upgrade or RIA--the energy content of the cavity is quite large requiring rf sources in excess of 10 kW. Conservatism in the control window specification would be quite costly; on the other hand loss of lock could have adverse effect on machine availability or beam property or even, in some cases, result in activation. We present a model to estimate the requirements to be placed on the rf control system based on the properties of the cavities, the FR-equency tuning system, and the characteristics of the accelerator

[en] Short communication

[en] A shaft door is patented with a folding ladder which may easily be opened from the top and bottom of the shaft. It excludes the opening of the door by falling objects which improves work safety. This door is suitable for access shafts to biological protective cabins for repairs and maintenance inside nuclear reactors and for other purposes. (Ha)

[en] The invention concerns the improvement of the locking mechanism for the gates of a personnel air lock for pressure and safety chambers with two gates. The locking device according to the invention is to have the effect that one door can only be opened if the other is closed. In addition, it is to be operated from within and from the outside. It therefore is proposed to fit locking elements in the form of radially protecting bayonet teeth at each door which are embraced in the locked position by locking elements in the form of a bayonet counter gearing mounted on the door impact frame. Further advantageous refinement of the device is described in detail. The invention can be applied for caisson work, safety rooms of nuclear reactor stations, air-conditional rooms etc. (RW)

[en] Radio frequency (RF) windows are historically a point where failure occurs in input power couplers for accelerators. To obtain a reliable, high-power, 350 MHz RF window for the Low Energy Demonstration Accelerator (LEDA) project of the Accelerator Production of Tritium program, RF windows prototypes from different vendors were tested. Experiments were performed to evaluate the RF windows by the vendors to select a window for the LEDA project. The Communications and Power, Inc. (CPI) windows were conditioned to 445 kW in roughly 15 hours. At 445 kW a window failed, and the cause of the failure will be presented. The English Electronic Valve, Inc. (EEV) windows were conditioned to 944 kW in 26 hours and then tested at 944 kW for 4 hours with no indication of problems

No abstract available

[en] The purpose of this paper is to present the results of a theoretical study pertaining to the feasibility of Phase Induced Amplitude Apodization (PIAA) units using deformable mirrors (DMs). We begin by reviewing the general derivation of the design equations driving PIAA. We then show how to solve these equations for square apertures and show the performance of pure PIAA systems in the ray optics regime. We tie these design equations into the study of edge diffraction effects and provide a general expression for the field after a full propagation through a PIAA coronagraph. Third, we illustrate how a combination of pre- and post-apodizers yields a contrast of 10^-10 even in the presence of diffractive effects, for configuration with neither wavefront errors or wavefront control. Finally, we present novel PIAA configurations over square apertures which circumvent the constraints on the manufacturing of PIAA optics by inducing the apodization with two square DMs. Such solutions rely on pupil size smaller than currently envisioned static PIAA solutions and thus require aggressive pre- and post-apodizing screens in order to mitigate for diffractive effect between the two mirrors. As a result they are associated with significant loss in performance, throughput in particular.

[en] Synthetic aperture interferometry (SAI) is a novel way of testing aspherics and has a potential for in-process measurement of aspherics [Appl. Opt.42, 701 (2003)].APOPAI0003-693510.1364/AO.42.000701 A method to measure steep aspherics using the SAI technique has been previously reported [Appl. Opt.47, 1705 (2008)].APOPAI0003-693510.1364/AO.47.001705 Here we investigate the computation of surface form using the SAI technique in different configurations and discuss the computational errors. A two-pass measurement strategy is proposed to reduce the computational errors, and a detailed investigation is carried out to determine the effect of alignment errors on the measurement process.