Usage of electron spectrometry

1. Usage of electron spectrometry • Studies of nuclear structure, decays and reactions • 1) Study of conversion electrons • 2) Study of electrons and positrons from beta decays • 3) Study of Auger electrons • 4) Determination of electron neutrino mass • 5) Study of di-lepton pairs at high-energy physics • B) Application • 1) Spectroskopy of electron energy losses with high • resolution • 2) Measurement of atomic level widths and binding energy of • electrons • 3) Study of molecular bonding from shifts of energies of • conversion electron lines Electron spectrum:1) Continuous – from beta decay bremsstrahlung ... 2) Discrete – conversion, Auger electrons

2. Study of conversion coefficients Common determination of gamma and electron intensities → determination of transition multipolarity E0 transitions → are realized only by conversion electrons Very often on beam measurement together with 4π detector systems for gamma ray detection Importance of correction on Doppler Shift (widening of line at spectrum) kinematic shift is described by Lorentz transformation: • - coordinate system connected with • moving nucleus Compound nucleus → same velocity reaction and CE → different nucleus velocity Spectrum of conversion electrons - transition near yrast line Determination of kinematics by nucleus detection

3. Study of electrons and positrons from beta decay Measurement of Fermi-Kurie graph: N(Ee) – number of electrons, F*(Z,Ee) – Fermi function, contains correction on Coulomb fields of nucleus and atomic electron cloud. mνc2 ≠ 0 → EMAX=Q - mνc2 Q – decay energy Schematic description of dependency Ne = f(Ee) in beta decay Square of neutrino mass is determined Necessity of very high resolution and Minimalization of energy loss possibilities (violation of spectrum shape) Fermi graph for decay of tritium 3H, which is mostly used for neutrino mass determination

4. Determination of neutrino mass Present limit on neutrino mass (experiments at Mainz and Troick): Determined limit for mν < 2-3 eV Obtained negative value of square mass Complications:1) Energy losses in target, molecule T2 2)Spectrometer stability Experiment KATRIN Integral electrostatic spectrometer Assumed sensitivity of spectrometer KATRIN Scheme of spectrometer KATRIN

5. Usage of pair spectrometers for searching of exotic particles decay Some hypothetical particles should havedecay channel to electron positron pair Vznikat by mohly například při srážkách těžkých iontů Pair spectrometer APEX as example – it was not determined for axion searching

6. combinato- rial background Au+Au 1 GeV/n 10-6 η → e+e- ρ→ e+e- ω→e+e- φ→e+e- 10-8 pn 10-10 π+π- anihilation 0.4 0.8 1.2 M(e+e-)[GeV/c2] Δ – Dalitz decay bremsstrahlung Decay of meson η Study of di-lepton pairs in high-energy physics Usage of track spectrometers CERES, NA50, HADES ... Momentum resolution is very important Sources of e+e- pairs: Dilepton „cocktail“ Combinatorial background – its description is very important

7. Spectroscopy of electron energy losses with high resolution Set-up:1) electron gun – electrons 2) electron spectrometer with high resolution Electron gun EG3000 and electron spectrometer ELS5000 of LK Technologies company Usage: 1) Surface studies by means of characteristic Auger electrons, electron scattering and diffraction 2) Structure studies XPS method – X-ray photoelectron spectroscopy – surface, chemical analysis