Richard C. Fernow

Energy dependence of spin-spin forces in 90°cm elastic p-p scattering

Abstract We measured d σ d t(90° cm ) for ↑+ p ↑→ p + p from 1.75 to 5.5 GeV/ c , using the Argonne zero-gradient synchrotron 70% polarized proton beam and a 70% polarized proton target. We found that the spin-spin correlation parameter. A nn , equals 60% at low energy, then drops sharply to about 10% near 3.5 GeV/ c , and remains constant up to 5.5 GeV/ c .

Simultaneous Measurement of 2 and 3 Spins in Proton Proton Elastic Scattering at 6-GeV/c

Abstract The elastic cross section for proton proton scattering at 6 GeV c was measured using a 70% polarized beam and a 75% polarized target at the Argonne ZGS. In the range P ⊥ 2 = 0.5 → 2.0( GeV c ) 2 we obtained small error measurements for the ↑↑, ↓↓ and ↑↓ initial spin states perpendicular to the scattering plane. At P⊥2 = 0.5 we also measured the recoil spin and found that the 5 different cross sections were very unequal.

Measurement of Proton Proton Elastic Scattering in Pure Initial Spin States at 11.75-GeV/c

Abstract The elastic cross section for proton proton scattering at 11.75 GeV/c was measured at the Argonne ZGS using a 50% polarized target. In the range p⊥2=0.6 → 2.2 (GeV/c)2 we obtained precise measurements of d σ d t(ij) for the ⇈ ⇊, and ⇅ initial spin states perpendicular to the scattering plane. We confirmed that the asymmetry parameter, A, decreases with energy in the diffraction peak, but is approximately energy-independent at large p⊥2. We found that the spin correlation parameter cnn acquires rather dramatic structure, and at large p⊥2 seems to grow with energy.

Radiation damage in polarized target materials

We examine some of the parameters which influence the decay of the polarization of polarized targets in an intense proton beam. We find that the usual characteristic flux for the polarization to drop to 1/e of its initial value does not provide a sufficient criterion to specify the radiation resistance of target materials. We give a more detailed method of evaluation including an empirical formula for the effect of annealing on the target polarization. During the course of a recent high energy physics experient a) we have accumulated a significant amount of data on the radiation resistance of diol and butanol polarized targets. The experiment was performed in an external proton beam at the Z.G.S. at Argonne National Laboratory. The results allow a better comparison of the suitability of various target materials when the target must be subjected to a high intensity beam. Diols have been used as polarized target materials because of their high proton polarization and relatively short polarizing times2). A diol is a hydrocarbon chain with two of the hydrogens replaced by -OH groups. The diols examined here are 1,2-ethanediol, OHCH2CH2OH, and 1,2-propanediol, CH3CH OHCH2OH. The target samples were prepared by mixing the diol and potassium dichromate under carefully controlled conditions of temperature, light, and pressure. The procedure was designed to give an optimum concentration of paramagnetic CrV complexes in the diol solution. Table 1 lists several properties of the diol samples: the liquid EPR derivative peak separation and the

Dynamic polarization in radiation resistant materials

Abstract Measurements of spin effects in small cross section processes have shown the need for more radiation resistant polarized target materials. We have examined the dynamic polarization of a number of substances which are known to be highly resistant to the formation of color centers with particular emphasis on toluene. We have also examined the relation between the maximum polarization and characteristic radiation flux constant to obtain a figure of merit for new materials.

Energy dependence of spin‐spin effects in p−p elastic scattering at 90°CM

Data are presented on the energy dependence of the spin-spin correlation parameter, Ann, for pp elastic scattering at 90°cm over the beam momentum range 6 to 12. 75 GeV/c. Ann is about 10% up to 8 GeV/c then climbs rapidly to a value of about 60% at 11 GeV/c. Our data indicate that Ann may depend only on the variable P ⊥ 2 and suggests that Ann may reach a limiting value of about 60%.