Gamma rays, angular correlation

The experimental techniques involved in measuring the angular correlation and the Doppler broadening of the two annihilation gamma-rays were introduced in section 1.3. These techniques rely on the fact that the motion of the positron-electron pair immediately prior to annihilation causes the two gamma-rays to be emitted in directions differing... 

Fer65] Ferguson AJ 1965 Angular correlation methods in gamma-ray spectroscopy (North-Holland, Amsterdam). 

Problem 3.6 The angular resolution of a standard ID angular correlation apparatus 0.5 milliradians. To what angular resolution is the energy resolution of a Ge detector at 51 IkeV (= 1.2keV) equivalent [Use p mocQ, where 9 is the deviation of a gamma ray from the system axis.]... 

R. Bauer, Carbonic anhydrase studied by perturbed angular correlation of gamma rays Thesis/Dissertation, University of Copenhagen, Niels Bohr Institute, 1976. 

Search for GRB Neutrinos. The AMANDA GRB search for correlated v emission relies on temporal (typically less than 100 s in duration) and angular information provided by BATSE and other satellites in the IPN network (Hurley et al., 1998). Initial search strategies for data collected between 1997-2000 (Hardtke et al., 2003) and for individual GRBs (Stamatikos et al., 2004), have assumed nearly concurrent emission within the duration of prompt gamma-ray emission (Tgo). A new search (Kuehn et al., 2004) also scans for neutrino emission prior to the Tgo start time. No excess was observed for either search method above the expected background from atmospheric v and poorly reconstructed... 

T. Butz, Nuclear quadrupole interactions studies by time differential perturbed angular correlations of gamma-rays, Z. Naturforsch. A 1996, 5/(5-6), 396-410. 

The relaxation effects as probed via the Mossbauer hyperfine interaction can be investigated by other methods which can be regarded as complementary to Mossbauer spectroscopy. The techniques of perturbed angular correlation of gamma rays (PAC) and positive muon spin rotation (pSR) spectroscopy will be briefly discussed here. A more detailed review can be found in Dattagupta (1981). 

The PAC experiment makes use of a nucleus which decays through successive gamma radiations yj and yj- The observation of yj in a fixed direction determines the spin orientation of the nucleus and the subsequent radiation j2 then has a definite angular correlation with respect to the direction of yj. If in the intermediate state of the gamma-ray cascade the nucleus is under the influence of a magnetic hyperfine interaction, the second radiation y2 carries with it information on this interaction. Hence the relaxation of the environment within the lifetime of the intermediate state of the nucleus manifests itself in a time-dependent magnetic hyperfine interaction. 

Cohen, S.G., 1967, Hyperfine interactions and angular distribution and correlations of nuclear gamma rays, in A.J. Freeman and R. Frankel, eds., Hyperfine Interactions... 

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