MFMP: Next replication - GlowStick 5.4 aka GlowShell

  • I haven't looked at the spectra, but if there are counts in the 511 keV region of interest, depending upon whether there is a narrow peak or a broadband spectrum, these could be due to (1) beta plus decay, which would show up as a peak; (2) bremsstrahlung for electrons with energies of some multiple of 511 keV, which would not reveal a peak in the higher energy region; or (3) characteristic (nuclear) gamma decays in the general neighborhood. I'll be interested to get a fuller description of the events and of the natural background.

  • That is pretty much what we did yesterday. We went higher in pressure, 3 bar absolute. That was added over maybe 5 minutes. The bleed to vacuum also was done over several minutes. At no time during the entire run did we see a deviation (above measurement jitter) between active and null temperatures, nor did we expect to.

    The data and what I recall from the live test seemed to suggest that this was done over 10-15 seconds, but I guess I could be wrong or looking at something else. The data has a sample rate of one every 10 seconds, and the jumps here show 1 or 2 at most.

  • Would you mind explaining what this means please? Whats a 511k ROI detector?

    That data input is a pulse counter for the Region Of Interest ("ROI") signal from the UCS30 Gamma Spectrometer. It is set to give a ~10 usec pulse for each detected gamma in the range of 500-520 keV. The Multi-Channel Analyzer ("MCA") is set for 4096 channels over the region of 25 keV to 1730 keV and the instrument was calibrated with a 137Cs source at the start of the run. The temperature of the NaI scintillator probe was included in the data set, in case correction for thermal drift was found to be needed. That temperature varied only a few degrees during the run, so the ROI discrimination should be accurate enough.

    The 511 keV signal originates from positron-electron annihilation which has been proposed by Piantelli as part of the reaction chain in Ni-H systems. For further details, refer to the Glowstick 5-4 live doc at