arXiv subjects

D. Nikas

Publications and source records attributed to D. Nikas.

7 recordsLinked to original sources

arXiv2009

An Improved Limit on the Muon Electric Dipole Moment

Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d=-0.1(0.9)E-19 e-cm, are all consistent with zero, we set a new muon EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.

hep-ex↗

arXiv2001

A Single Shot, Sub-picosecond Beam Bunch Characterization with Electro-optic Techniques

In the past decade, the bunch lengths of electrons in accelerators have decreased dramatically to the range of a few picoseconds \cite{Uesaka94,Trotz97}. Measurement of the length as well as the longitudinal profile of these short bunches have been a topic of research in a number of institutions \cite{Uesaka97,Liu97,Hutchins00}. One of the techniques uses the electric field induced by the passage of electrons in the vicinity of a birefringent crystal to change its optical characteristics. Well-established electro-optic techniques can then be used to measure the temporal characteristics of the electron bunch. In this paper we present a novel, non-invasive, single-shot approach to improve the resolution to tens of femtoseconds so that sub-millimeter bunch length can be measured.

physics.acc-ph↗

arXiv2000

ElectroOptical measurements of ultrashort 45 MeV electron beam bunch

We have made an observation of 45 MeV electron beam bunches using the nondestructive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with the optical beam path distance from the electron beam. The risetime of the signal was bandwidth limited by our detection system to \~70ps. An EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. The EO technique may be ideal for the measurement of bunch structure with femtosecond resolution of relativistic charged particle beam bunches.

hep-ex↗

arXiv2000

Electrooptical Measurements of Ultrashort 45 MeV Electron Beam Bunches

We have measured the temporal duration of 45 MeV picosecond electron beam bunches using a noninvasive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with distance from the electron beam. The risetime of the temporal signal was limited by our detection system to ~70ps. The EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. It has a distinctively long decay time constant and signal polarity opposite to that due to the field induced by the electron beam. The electro-optical technique may be ideal for the measurement of bunch length of femtosecond, relativistic, high energy, charged, particle beams.

hep-ex↗

arXiv2000

First Electrooptical Detection of Charged Particles

We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a birefringent crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured in a single shot, 120 ps, was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds promise for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

hep-ex↗

arXiv2000

Electrooptical Detection of Charged Particles

We have made the first observation of a charged particle beam by means of its electro-optical effect on the polarization of laser light in a LiNbO3 crystal. The modulation of the laser light during the passage of a pulsed electron beam was observed using a fast photodiode and a digital oscilloscope. The fastest rise time measured, 120 ps, was obtained in the single shot mode and was limited by the bandwidth of the oscilloscope and the associated electronics. This technology holds promise for detectors of greatly improved spatial and temporal resolution for single relativistic charged particles as well as particle beams.

hep-ex↗

arXiv1999

A Decommissioned LHC Model Magnet as an Axion Telescope

The 8.4 Tesla, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utilized as a macroscopic coherent solar axion-to-photon converter. Numerical calculations show that the integrated time of alignment with the Sun would be 33 days per year with the magnet on a tracking table capable of $\pm 5^o$ in the vertical direction and $\pm 40^o$ in the horizontal direction. The existing lower bound on the axion-to-photon coupling constant can be improved by a factor between 50 and 100 in 3 years, i.e., $g_{aγγ} \lesssim 9\cdot 10^{-11} GeV^{-1}$ for axion masses $\lesssim$ 1 eV. This value falls within the existing open axion mass window. The same set-up can simultaneously search for low- and high-energy celestial axions, or axion-like particles, scanning the sky as the Earth rotates and orbits the Sun.

astro-ph↗