On possibility of measurement of the electron beam energy using absorption of radiation by electrons in a magnetic field

The possibility of the precise measurement of the electron beam energy using absorption of radiation by electrons in a static and homogeneous magnetic field in a range up to a few hundred GeV energies, was considered in [1]. With the purpose of experimental checking of this method in a range of several tens MeV energies, the possibility of measurement of absolute energy of the electron beam energy with relative accuracy up to 10^{-4} is examined in details.Comment: 14 pages, 10 figure

Standard and Null Weak Values

Weak value (WV) is a quantum mechanical measurement protocol, proposed by Aharonov, Albert, and Vaidman. It consists of a weak measurement, which is weighed in, conditional on the outcome of a later, strong measurement. Here we define another two-step measurement protocol, null weak value (NVW), and point out its advantages as compared to WV. We present two alternative derivations of NWVs and compare them to the corresponding derivations of WVs.Comment: 11 pages, 2 figures. To appear in Quantum Theory: A Two-Time Success Story: Yakir Aharonov Festschrif

Spectroscopic Investigation of Fast (ns) Magnetic Field Penetration in a Plasma

The time dependent magnetic field spatial distribution in a coaxial positive-polarity Plasma Opening Switch, carrying a current ~135 kA during ~100 ns, was investigated by two methods. In the first, ionic line emission was observed simultaneously for two polarizations to yield the Doppler and Zeeman contributions to the line profiles. In the second method, the axial velocity distribution of ions was determined, giving the magnetic field through the ion equation of motion. This method requires knowledge of the electron density, here obtained from the observed particle ionization times. To this end, a lower bound for the electron kinetic energy was determined using various line intensities and timedependent collisional-radiative calculations. An important necessity for POS studies is the locality of all measurements in r, z, and θ. This was achieved by using laser-evaporation to seed the plasma non-perturbingly with the species desired for the various measurements. The Zeeman splitting... The Zeeman splitting a..