INDEX Magnetic particles

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Fig. 4. Static force index (Tesla(ATesla/Adistance)) for varying particle shapes, where K is the bulk density of material in kg/m. The plate has dimensions of 6 X 76 X 76 mm the bolt has dimensions of 6 x 25 mm. The horizontal line represents the distance from the magnet face.

The ion-source of the separator is fed by a capillary transporting the recoils therma— lized in the He-jet chamber. The separator beam is extracted at right angle to the axis of the beam line and then travels in a 120° magnet of index n=1/2. From the focal plane the mass-separated beam is then transported by means of a 6m long Einzel lens to a well-shielded collection chamber. A programmable tape-trans port device carries the activity to the counting station where X-rays, y-rays and particles are detected. 

The first term in eq. (1) Ho represents the spherical part of a free ion Hamiltonian and can be omitted without lack of generality. F s are the Slater parameters and ff is the spin-orbit interaction constant /<- and A so are the angular parts of electrostatic and spin-orbit interactions, respectively. Two-body correction terms (including Trees correction) are described by the fourth, fifth and sixth terms, correspondingly, whereas three-particle interactions (for ions with three or more equivalent f electrons) are represented by the seventh term. Finally, magnetic interactions (spin-spin and spin-other orbit corrections) are described by the terms with operators m and p/. Matrix elements of all operators entering eq. (1) can be taken from the book by Nielsen and Koster (1963) or from the Argonne National Laboratory s web site (Hannah Crosswhite s datafiles) http //chemistry.anl.gov/downloads/index.html. In what follows, the Hamiltonian (1) without Hcf will be referred to as the free ion Hamiltonian. 

Hereafter, taking into account the axial symmetry of the problem that implies m = —m [see Eq. (4.333)], we will use only one upper index in the notation of the coefficient (4.334) Qfv. Further on, however, when expanding Q with respect to the probing field amplitude we will have to indicate the order of the approximation by an additional upper index. To avoid confusion, this index will be kept inside curled braces [e.g. <2 y2 ]- In a reduced form, namely, at l = m = m = 0, the parameters Q render customary uniaxial orientational order parameters of the particle axes in a suspension (magnetic fluid). In this case their meaning is illustrated by... 

Many complex fluids contain orientable molecules, particles, and microstmctures that rotate underflow, and under electric and magnetic fields. If these molecules or microstructures have anisotropic polarizabilities, then the index of refraction of the sample will be orientation-dependent, and thus the sample will be birefringent. In general, the anisotropic part of the index of refraction is a tensor n that is related to the polarizability a of the sample. The polarizability is the tendency of the sample to become polarized when an electric field is applied thus P = a E, where P is the polarization and E is the imposed electric field. When the anisotropic part of the index of refraction is much smaller than the isotropic part (the usual case), the index-of-refraction tensor n can be related to a by the Lorentz-Lorenz formula ... 

In outer space, remote from the shielding influence of the earth s magnetic field, the absorbed dose index rate from solar protons emitted during solar flares can be very high. For example, it has been estimated that the absorbed dose indices in outer space from the solar proton event of 10 July 1959 were from protons 3.6, 1.7, and 0.4 Gy behind shielding of 1, 2 and 5 g cm, respectively, and from alpha particles the corresponding values were 1.5,0.3 and 0.05 Gy, respectively (Curtis, 1974). However, the Apollo missions did not experience any measmable solar particle events (English et al., 1975). 

The ability of anisotropic and anisometric particles to assume some co-orientation in external force fields is not only responsible for significant changes in scattering properties but also causes birefringence (double refraction), i.e., the average refractive indexes of two beams polarized in perpendicular planes happen to be different. The specific orientation of particles and birefringecne may be caused by the action of electric field (Kerr effect), magnetic field (Cotton-Mouton effect), or in the case of anisotropic particles by flow of medium (Maxwell effect) [25]. 

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