Gamma ray production in paraffin by cosmic rays

Gamma ray production in paraffin by cosmic ray

The low energy gamma-ray spectrum in space

Balloon, satellite and other deep space probe observations on the intensity of low energy (0.1-10 MeV) gamma-rays are carefully examined with a view to understand the existing anomalies in their intensities and energy spectra. The observed spectral data is "unfolded" to deduce the true gamma-ray energy spectrum. The recently observed flattening in the spectral shape at about 1 MeV is shown to be likely to arise as a result of the gamma-ray detector response to a simple power law input spectrum

The study of spurious scattering in nuclear emulsions and the effect of higher order differences in scattering measurements

By considering the higher order differences in the scattering measurement, a new approach of reducing the spurious scattering in nuclear emulsions is discussed. The possible effect of turbulence during the developing stage is discussed in brief

The diffuse cosmic gamma rays

A careful and objective analysis is made of the available experimental observations which claim evidence for the existence of a shoulder in the spectrum of the diffuse cosmic gamma rays in the energy range of 1-40 MeV. In this, special cognisance is taken of the experimental data and theoretical calculations of the Bombay Group. These considerations cast serious doubts on the reliability of the high flux values obtained by many experimenters in this energy region emphasizing thereby the need for great caution in interpreting the shoulder as due to cosmological effects with far reaching implications

Diffuse cosmic gamma rays observed at an equatorial balloon altitude

A 3"×3" NaI(T1) crystal-photomultiplier assembly with a 4 π charged particle anticoincidence shield is used to determine the gamma ray spectrum in the energy region of about 100 keV to 8.5 MeV at a balloon altitude of 4.7 g cm-2 over Hyderabad, India (geomagnetic latitude ˜ 8°N). The atmospheric growth curves are used to obtain the contribution of the diffuse cosmic gamma ray flux in the above energy range. The cosmic photon flux thus deduced up to about 8.5 MeV is consistent with a continuation of the power law spectrum observed at energies between 20 and 200 keV with an index of ˜-2.3, and hence contradicts the flattening trend observed in ERS-18 at an energy of a few MeV

Energetic neutrons and gamma rays measured on the Aryabhata satellite

An experiment to measure energetic neutrons and gamma rays in space was launched in the first Indian scientific satellite, Aryobhata, on April 19, 1975. From this experiment, the first measurements in space of the Earth's albedo fiux of neutrons of energy between 20 and 500 MeV have been made; the values obtained for two mean geomagnetic vertical cut-off rigidities of 5.6 and 17.0 GV are (6.3±0.4)×10-2 and (1.4±0.3)×10-2 neutrons cm-2 sec-1 respectively. These measurements confirm that protons arising from cosmic ray albedo neutron decay, can adequately account for the protons in the inner radiation belt. Observations on gamma rays of energy between 0.2 and 24 MeV have enabled the determination of the total background gamma ray flux in space as a function of latitude. This in turn has permitted useful information on the diffuse cosmic gamma rays. We have also observed four events that showed sudden increases in the gamma ray counting rates between 0.2 and 4.0 MeV. Observational details of these events are given

A method for detecting the possible existence of high energy deuterons in the primary cosmic radiation

A method which can be used for detecting the presence of high energy deuterons in the primary cosmic radiation is described. The suggested method takes advantage of the fact that when only the neutron of the incoming deuteron takes part in a collision and gives rise to a star in a nuclear emulsion, the proton continues in the forward direction almost undeviated. Such stars referred to as (d, p) stars, can provide evidence that the incoming particle is a deuteron. In order to use this method it is necessary to know: (i) the interaction mean free path λd of high energy deuterons in nuclear emulsions; and (ii) the proportion f(d, p) of deuteron induced interactions in which only the neutron takes part. These have been determined to be λd=15.8 cm and f(d, p)=0.4. The suggested method is applicable if deuterons constitute ≥ 5% of the singly charged particles in the primary radiation