Preliminary Investigations of Saudi Fluorite for Radiation Dosimetry
A. M. Alsoraya
The general dosimetric properties of local natural CaF2 are investigated using the thermoluminescence technique. It shows very good dosimetric properties with low fading and linear dose response ( ). In addition to that, the trap parameters such as activation energy, kinetic order, sensitivity and fading were undertaken to satisfy the feasibility of using the present sample as - ray dosimeter.
COMPARATIVE STUDIES BETWEEN SAND, ASPHALT AND CONCRETE AS SHIELDING MATERIALS AGAINST FISSION NEUTRONS·
A benchmark experiment was set up to study dose rate attenuation of fission neutrons in concrete, sand and asphalt. neutron source was used for fission neutrons. The neutron field intensities were measured by a plastic NE 102 scintillation counter. Dose rate factor was determined with the help of a neutron survey meter. The results suggest that ) the desert sand provides reasonably good protection against fission neutrons.
Relative Efficiency Determination of a Ge(Li) Detector in the Energy Range from O. 08 - 2 . 5 MeV
M. A. Farouk and A. M. Alsoraya
Relative full energy peak efficiency, between 0.08 and 2.50 MeV, of the CANBERRA, model 7229 - 7500 Ge(Li) gamma ray detector is described. The measurements have been performed with gamma rays from 182W, and 226Ra radio-active sources. As a test of the accuracy of the efficiency curve, obtained in this experiment, the relative intensities of more intensive gamma ray transitions in. the decay of 133Ba have been measured and compared with the results of other authors.
Reactions and from
1.7 to 2.5 MeV
G. U. Din and A. M. AlSoraya
J. A. Cameron, V. P. Janzen, and R. B. Schubank
The yields of the (p,g) and (p,p'g) reactions on 50Cr were measured in the proton energy range 1.7 to 2.5 MeV with an energy resolution <2 keV. In all, 72 resonances were found, mostly in both channels. Nine resonances, at 1.936, 1.942, 2.030, 2.042, 2.113, 2.141, 2.187, 2.303, and 2.408 MeV were determined to be close multiplets. Gamma-ray spectra were measured at 53 resonances, including the multiplets. Angular distributions of the capture g transitions at 40 resonances and of the transition in 50Cr at 27 resonances were measured. The gamma decay schemes of the resonances provided information on 43 excited states of 51Mn up to 5.174 MeV. Bound levels at 3.029, 3.835, 3.877, 3.955, 4.006, 4.046, and 4.153 MeV were populated for the first time in the (p,g) reaction and their decay schemes were determined. Significant revisions of the decay schemes of the 2.276, 2.702, 2.893, 3.131, 3.292, 4.450, 4.540, 5.074, 5.129, and 5.174 MeV levels have resulted from the large number of resonances studied. Spins and parities for many resonances and bound states of 51Mn have been determined from an extensive set of angular distribution measurements. In the proton energy range studied, 13 resonances are proposed as isobaric analogs of excited states from 2.704 to 3.207 MeV in 51Cr.
THE POLARIZATION OF NEUTRONS FROM THE 2H(d,n)3He REACTIONS FOR DEUTERON ENERGIES FROM 35 TO 275 keV
A. M. ALSORAYA and R. B. GALLOWAY
The dependence on deuteron energy of the polarization' of the neutrons emitted at 45° from the 2H(d, n)3He reaction in the range 35 to 275 keV, was determined from the asymmetry in the scattering of the neutrons by 4He. There is no indication of the much discussed possible resonance at about 100 keV deuteron energy. The results are discussed in relation to the general theoretical treatment of the 2H-2H interaction put forward by Boersma.
NUCLEAR REACTIONS 2H(d, n), E = 35-275 keV; measured polarization .
226Ra AS A STANDARD SOURCE FOR EFFICIENCY CALIBRATION OF Ge(Li) DETECTORS
M.A. FAROUK and A.M. AL-SORAYA
The relative intensities of gamma-rays resulting from the decay of 226Ra in equilibrium with its short-lived daughters have been measured using two different high resolution Ge(Li) detectors. The accuracy of the measurements does not exceed 2.5%. The most intense components of gamma-rays from thin 226Ra are recommended for use as a calibration standard for Ge(Li) detectors in the energy range from 186 keV to 3.050 MeV. J
Low-lying proton resonances of spin in 51Mn and 53Mn
G. U. Din and A. M. AlSoraya
J. A. Cameron and J. Sziklai
Spin resonances have been observed in proton capture by 50Cr at Ep= 2.397 MeV and by 50Cr at Ep= 2.680 and 2.686 MeV, 0.80, and 1.45 MeV below the respective g9/8 analog resonances.
In studies of isobaric analog states (IAS) in proton capture, much attention has been paid to g9/8 states. In some systems, such as 59Cu, the g9/8 IAS is strongly concentrated, while in others, such as the M n isotopes, considerable fragmentation occurs, though still over a relatively limited energy range (about 0.1 MeV). At roughly half the excitation energy of the IAS is a further level, the anti-IAS (AIAS), connected to the IAS by large M1 electromagnetic matrix elements. Wide observed variations in the M I gamma decay rate from one nucleus to another through the fp shell have been attributed to interference induced by various kinds of core excitation acting within the lower 1sospin components. These models produce a spectrum of (excited states above the AIAS. In 53Mn and 59Cu, (3He,d) experiments appear to have identified some of these, but until recently no evidence was found for such levels in (p,g ) experiments. We have already reported the discovery of a capture resonance 0.7 MeV below the IAS in 59CU and its properties have been verified by further experiments, As in the case of the main IAS fragments, the de- \ cay is principally by an M I transition to the AIAS. The presence of a measurable E2 admixture in the)' decay and the strength of the proton decay to the first 2 + state in 58Ni hint strongly that the core excitation is of E2 character and produces a wave function admixture in the capture state as well as in the AIAS. Although several other 1=4 transitions were reported in 58Ni(3He,d)59Cu, no other proton resonance has been found from threshold to the IAS.
Thermal-neutron fluxes produced in Glycerin or base oil and water
M.A RAOOF and A.M.AL-SORAYA
Thermal-neutron fluxes produced in water, glycerin or base oil by two isotopic sources, 1 Ci (Am-Be) and 1.07 mCi (252Cf), used in turn, were measured by Au-foil activation. Activities produced in bare and cadmium-covered foils were determined with a 3 in. x 3 in. NaI(Tl) scintillation counter.
For mobile radiographic units, several organic moderators have been proposed such as polyethylene, glycerin, nylon, perspex and transformer oil . Thermal-neutron fluxes in water for the isotopic sources 241Am-Be, 124Sb-Be  and 239pu-Be, 241Am-Be  have been reported earlier, but there have not been sufficient studies of thermal-neutron flux distributions in organic moderators, particularly when there are encouraging prospects of such units with the spontaneous fission source 252Cf . From the prospective high-density hydrocarbons, glycerin and locally produced petromin base oil 100 (similar to transformer oil, rich in hydrogen and free from any chemical additives) were chosen for the present studies.