We describe an experimental setup for making precision measurements of relative β-decay rates of (22)Na, (36)Cl, (54)Mn, (60)Co, (90)Sr, (133)Ba, (137)Cs, (152)Eu, and (154)Eu. The radioactive samples are mounted in two automated sample changers that sequentially position the samples with high spatial precision in front of sets of detectors. The set of detectors for one sample changer consists of four Geiger-Müller (GM) tubes and the other set of detectors consists of two NaI scintillators. The statistical uncertainty in the count rate is few times 0.01% per day for the GM detectors and about 0.01% per hour on the NaI detectors. The sample changers, detectors, and associated electronics are housed in a sealed chamber held at constant absolute pressure, humidity, and temperature to isolate the experiment from environmental variations. The apparatus is designed to accumulate statistics over many years in a regulated environment to test recent claims of small annual variations in the decay rates. We demonstrate that absent this environmental regulation, uncontrolled natural atmospheric pressure variations at our location would imprint an annual signal of 0.1% on the Geiger-Müller count rate. However, neither natural pressure variations nor plausible indoor room temperature variations cause a discernible influence on our NaI scintillator detector count rate.
A 1 μm diameter platinum wire resistance thermometer has been used to measure temperature fluctuations generated during a static GEM-60 rocket motor test. Exact and small-signal relationships between acoustic pressure and acoustic temperature are derived in order to compare the temperature probe output with that of a 3.18 mm diameter condenser microphone. After preliminary plane wave tests yielded good agreement between the transducers within the temperature probe’s ∼2 kHz bandwidth, comparison between the temperature probe and microphone data during the motor firing show that the ±∼3 K acoustic temperature fluctuations are a significant contributor to the total temperature variations.
Evidence is presented for neutrons emanating from partially deuterated titanium foils (TiDx) subjected to non-equilibrium conditions (charged particle results appear in a separate paper in this proceedings). Two types of deuteriding and varied currents were employed to produce the non-equilibrium conditions within the foils, and emissions lasted over long durations. Experiments were conducted in a deep underground tunnel having significant rock overburden to diminish cosmic backgrounds. Subtracting background rates and taking into account detector efficiency, we found the highest net yield to be 57 ± 13 counts/hour. Yields for all runs are reported and the theoretical fusion reaction defined. Totaling all experiments, reproducibility was 40%. 525 526
We present evidence for energetic charged particles emanating from partiallydeuterided titanium foils (TiDx) subjected to non-equilibrium conditions. To scrutinize emerging evidence for low-temperature nuclear reactions, we investigated particle yields employing three independent types of highly-sensitive, segmented particle detectors over a six-year period. One experiment measuring neutron emission from TiDx foils showed a background-subtracted yield of 57 ± 13 counts per hour. (The neutron experiments are discussed in a separate paper in this proceedings.) A second experiment, using a photo-multiplier tube with plastic and glass scintillators and TiDx registered charged particle emissions at 2,171 ± 93 counts/hour, over 400 times the background rate. Moreover, these particles were identified as protons having 2.6 MeV after exiting the TiDx foil array. In a third experiment, coincident charged particles consistent with protons and tritons were observed with high reproducibility in two energy-dispersive ion-implanted detectors located on either side of 25-micron thick Ti foils loaded with deuterium. 510Our overall data therefore strongly suggest low-level nuclear fusion in deuterided metals under these conditions according to the fusion reactions d + d → n(2.45 MeV) + 3 He(0.82 MeV) and d + d → p(3.02 MeV) + t(1.01 MeV), with possibly other nuclear reactions occurring. Important advances were particle identifications, and repeatability approaching 80% for coincident charged particle emissions. Metal processing and establishing non-equilibrium conditions appear to be important keys to achieving significant nuclear-particle yields and repeatability.
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