Measurement of the 171Tm beta spectrum.

The beta spectrum of the main transition of the ß- decay of 171Tm was measured using a double focalizing spectrometer. The instrument was lately improved in order to reduce its low energy threshold to 34 keV. We used the spectrometer to measure the beta spectrum end-point energy of the main transition of 171Tm decay using the Kurie plot formalism. We report a new value of 97.60(38) keV, which is in agreement with previous measurements. In addition, the spectrum shape was compared with the ξ-approximation calculation where the shape factor is equal to 1 and good agreement was found between the theory and the measurement at the 1% level.

Continued skirmishing on the wave-particle frontier.

Historical developments in electron microscopy where understanding lies at the interface between the particle and wave pictures of the electron are reviewed. Electron optics has remained mainly particle-based but imaging is now substantially dependent on wave methods which are now pushing it to new heights. Spectroscopy in the low loss region has used Fermi's classical electron model which can also describe the main effects of Johnson noise. It is confirmed that the RMS Johnson noise scattering of an aloof beam electron is proportional to its wavelength and to the square root of the temperature. If the conductivity σ is high, it is independent of σ. In the performance of magnetic spectrometers, the angular deflections due to the walls may be less significant than that generated in the slits. The angular deflections due to the many bremmstrahlung events in the spectrometer seem to be negligible but the influence of Johnson noise on them is beyond the scope of the classical Fermi theory and will need to be addressed by the quantum mechanical spontaneous wave theory.

Comparison of space radiation GCR models to AMS heavy ion data.

Galactic cosmic rays (GCR) are a constant source of radiation that constitutes one of the major hazards during deep space exploration missions for both astronauts and hardware. In this work, GCR models commonly used by the space radiation protection community are compared with recently published high-precision, high-resolution measurements of cosmic ray lithium, beryllium, boron, carbon, nitrogen, and oxygen fluxes along with their ratios (Li/B, Li/C, Li/O, Be/B, Be/C, Be/O, B/C, B/O, C/O, N/B, N/O) from the Alpha Magnetic Spectrometer (AMS). All of the models were developed and calibrated prior to the publication of this AMS data, therefore this is an opportunity to validate the models against an independent data set. This paper is a compliment to the previously published comparison of GCR models with AMS hydrogen, helium, and the boron-to-carbon ratio (Norbury et al., 2018).

Comparison of space radiation GCR models to recent AMS data.

This paper is the third in a series of comparisons of American (NASA) and Russian (ROSCOSMOS) space radiation calculations. The present work focuses on calculation of fluxes of galactic cosmic rays (GCR), which are a constant source of radiation that constitutes one of the major hazards during deep space exploration missions for both astronauts/cosmonauts and hardware. In this work, commonly used GCR models are compared with recently published measurements of cosmic ray Hydrogen, Helium, and the Boron-to-Carbon ratio from the Alpha Magnetic Spectrometer (AMS). All of the models were developed and calibrated prior to the publication of the AMS data; therefore this an opportunity to validate the models against an independent data set.

Preliminary beta spectrum measurements using a magnetic spectrometer.

We report the performances of a double focusing magnetic beta spectrometer. The energy resolution was measured using conversion peaks of Cs-137 and Ba-133 at 0.73% for 624 keV, and 1.33% for 124 keV. The counting efficiency as a function of the energy was estimated using a P-32 source and was used to correct the measured spectra of Cs-137. The result was compared with the theoretical spectrum and we found a good agreement.