By analysis of the observations of the cosmic-ray ionization on the Hafelekar (2300 meters above sea level, 48 North geomagnetic lat, ) during five years the existence of a seasonal variation with an amplitude of &0.9 percent has been proved. Reduction of the monthly means to the annual mean temperature diminishes the amplitude of the 12-month wave to one-half without eliminating it. This agree...

Multiply protonated peptides and proteins in the gas phase can respond to near edge X-ray absorption in three different ways: (i) non dissociative ionization and ionization accompanied by loss of small neutrals, both known to dominate for proteins with masses in the 10 kDa range. (ii) Formation of immonium ions, dominating for peptides in the 1 kDa range. (iii) Backbone scission leading to sequ...

We present predictions for two statistical measures of the hydrogen reionization process at high redshift. The first statistic is the number of neutral segments identified in spectra of high-redshift QSOs as a function of their length. The second is the cross-correlation of neutral regions with possible sources of ionizing radiation. These independent probes are sensitive to the topology of the...

Photoionization has been a highly selective method for the preparation of polyatomic molecular ions [1]. VUV light, usually of low intensity, must be employed; the produced ion flux has, however, often been insufficient for many interesting appli­ cations. Classical methods have employed discharge lamps or, more recently, synchrotron radiation [2]. The former is limited to a few wavelengths a t...

An experimental method (the two-dose-rate method) for the correction of general recombination losses in liquid ionization chambers has been developed and employed in experiments with different liquids and radiation qualities. The method is based on a disassociation of initial and general recombination, since an ionized liquid is simultaneously affected by both of these processes. The two-dose-r...

The use of the "thimble" ionization chamber (Fingerhutkammer) has in the past been the only method for comparing the primary X-ray standards of different laboratories, hence the precise calibration of two thimble chambers is discussed in this paper. Five principal factors determine the accuracy of such a calibration, and it is shown that the errors are all, in general, in the same direction. It...

Ion recombination in ionization chambers is usually considered as a side effect, which influences the accuracy of the determination of the absorbed dose. This is generally true for volume recombination, but not always for initial recombination, i.e. the recombination which occurs between the ions created in the same track of a single ionizing particle or resulting from a single ionization event...

The laser produced plasma from the multi-component target YBa2Cu307 was analyzed using Michelson interferometry and time resolved emission spectroscopy. The interaction of 10 ns pulses of 1.06 #m radiation from a Q-switched Nd:YAG laser at laser power densities ranging from 0.55 GW cm 2 to 1.5 GW cm 2 has been studied. Time resolved spectral measurements of the plasma evolution show distinct fe...

Analysis of the evolution of submillijoule few-cycle light pulses in an ionizing gas reveals physical mechanisms and scenarios enabling the generation of high-intensity supercontinuum radiation compressible to singlecycle pulse widths. The main properties of supercontinuum generation in this regime are analyzed by numerically solving a spatiotemporal evolution equation for a few-cycle light fie...

We study the classical and quantal ionization dynamics of a one-dimensional system by strong, low-frequency electric fields with slowly varying envelopes. We show that classical ionization can be described using the principle of adiabatic invariance, if the driving frequency is sufficiently small, and that after ionization the atomic potential does not significantly alter the motion. This dynam...