Dieter Seeliger

Search for DD-fusion neutrons during heavy water electrolysis

Abstract By a large volume liquid scintillation detector and some other neutron and γ-ray detectors the radiation obtainedby the electrolysis of heavy water with a palladium cathode was measured. An indication is found for a weak generation of fast neutrons (0.1 s−1 of about 2.5 MeV).

New method for measurement of energy and angular distributions of prompt fission neutrons

The energy (E) and the angle (θ) dependent emission probabilities N(E, θ) of prompt fission neutrons are measured by neutron time-of-flight spectroscopy as well as by a direction-sensitive method of fragment spectroscopy based on two parallel-plate avalanche counters (PPAC, one position-sensitive). Due to the determination of θ by the measurement of fragment direction for a fixed neutron detector position systematic errors are considerably reduced. The arrangement permits the precise measurement of neutron angular distributions depending on E for the whole angular range (180°) with a rather high angle point density (up to 120 per 180°). The angular resolution amounts to ⪆3° depending on the chosen geometry. Pulse shape discrimination is used for background (γ-rays, cosmic muons) suppression when employing NE213 scintillators for neutron detection (1–10 MeV range). 6Li-glass scintillators serve for the N(E, θ) measurement at low energy. The experimental setup, the multiparameter data handling, and the analysis procedures including corrections are described. Results on 252Cf(sf) neutron emission covering the energy range 0.1–10 MeV (up to 18 MeV in the polar direction) are presented and discussed in comparison with previous data.

Evidence for the Production of d-d Fusion Neutrons during Electrolytic Infusion of Deuterons into a Palladium Cylinder

A lengthy experiment for the observation of deuteron-deuteron (d-d) fusion neutrons emanating from a massive palladium cylinder is described. The experimental results are discussed in the framework of a plasmalike model for fusion in condensed matter, resulting in fusion rates of {lambda}{sup pl}{sub d{minus}d} = (1.19 {plus minus} 0.15) {times} 10{sup {minus}44} s{sup {minus}1}.

Observation of d-d fusion neutrons during degassing of deuterium-loaded palladium

Experiments with two massive deuterium-loaded palladium samples designed to search for deuteron-deuteron (d-d) fusion during thermal degassing are described. In the heavier of the two samples, which has a total mass of [approximately] 0.5 kg, during deuterium expulsion from the metal, a significant neutron excess count rate was detected by two independent NE-213 scintillation neutron detectors. The maximum time-dependent excess count rate corresponds to a d-d reaction rate of (3 [+-] 1) [times] 10[sup [minus]25] per deuteron pair per second. From detector pulse height spectra, the energy of the neutrons is determined to be [approximately] 2.5 MeV, as expected for d-d fusion neutrons. 10 refs., 10 figs., 2 tabs.

A simple plasma model for the description of d-d fusion in condensed matter

AbstractA simple plasmalike model that describes the time behavior of the deuteron-deuteron (d-d) fusion reaction rate as a function of charging time is presented. When used to describe the experimental shape of d-d neutron production rates averaged over broad time intervals, the model gives reasonable agreement. The fusion rates obtained from this comparison are of the order of the magnitude of effects that could be expected by the combination of electron screening and fluctuation enhancement. The model allows predictions of the conditions under which d-d fusion neutrons in condensed matter might be observed and explains why, in many cases, no effects are observed.

Uranium Removal from Flood Water at Königstein Mine

The acidic flood water from the former in-situ leaching (ISL) mine Konigstein is characterized by considerable U concentrations (about 10 to 60 mg/1). Flood water treatment includes (i) U removal by ion exchange (IX) and further U processing by multi-stage elution, H2O2 precipitation of U, and U oxide washing and de-watering and (ii) water cleaning in a HDS plant. The former U plant at the site was converted and technologically adapted to meet the specific requirements determined by controlled flooding, by disposal/usability criteria for U as well as by legislation and authorities.

Indication for the temporary production of deuteron-deuteron fusion neutrons during electrolytic infusion of deuterons into a massive palladium slab

In this paper two successive long-duration experiments for the observation of deuteron-deuteron (d-d) fusion neutrons emanating from a massive palladium slab are described. The experimental effects observed are discussed through the use of a simple plasmalike model for the time dependence of fusion reactions in condensed matter, which is modified for a plane geometry. This results in a plasma fusion rate of {lambda}{sup Pl}{sub d-d} = (1.0 {+-} 0.15) {times} 10{sup {minus}44}s{sup {minus}1}. While plasmalike behavior leading to observable d-d fusion reaction intensities occurs temporarily, under nonequilibrium conditions of electrolytic charging only, for permanently occurring d-d molecular fusion in the fully loaded palladium slab from the experiments, only an upper limit can be set, which is given by {Lambda}{sup d-d} {lt} 10{sup {minus}26}s{sup {minus}1}.

Temperature shift of neutron resonances

Temperature-induced shift of neutron resonances have been experimentally observed studying low-energy resonances of 103Rh, 109Ag, l61Dy and l63Dy with a time-of-flight spectrometer at the Dubna pulsed reactor The shifts are regarded as an analogue to the second-order Doppler effect in Mossbauer gamma-ray spectroscopy.

Detailed investigations of fission neutron emission

Abstract Two parallel-plate avalanche counters (one position-sensitive) for fragment detection (time of flight, direction) and two NE213 scintillators for neutron detection (time of flight, scintillator response) are used to measure the Cf-252(sf) neutron double-differential emission probability N(E, Θ), i.e. in dependence of laboratory system (LS) energy and LS angle of neutron emission with reference to light-fragment direction. First results are compared with complex statistical-model calculations.

Theoretical study of the Cf-252(SF) neutron spectrum

Abstract The Cf-252(sf) neutron spectrum was calculated in the framework of both the complex cascade evaporation model (CEM) and the generalized Madland-Nix model (GMNM). A comparison with recent experimental data is presented. Specifically the CEM including the emission anisotropy in the center-of-mass frame (CMS) yields a good agreement with measured data between 1 keV and 20 MeV.