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High-spin states in odd-odd 164 Lu have been studied using 19 F and 23 Na induced fusion-evaporation reactions. Three strongly coupled rotational bands have been established and three decoupled bands were tentatively assigned to 164 Lu. The band crossing frequencies, energy sig-nature splittings, and relative transition probabilities were deduced from experimental data and compared with neighboring even-even and odd- A nuclei. An anomalously large band crossing frequency was observed in the excited band, and a pronounced signature inversion was observed in the yrast band of 164 Lu. These anomalies may be associated with residual neutron-proton interactions.

Cross sections for elastic scattering and quasielastic transfer have been measured for {sup 32}S+{sup 96,100}Mo at {ital E}{sub lab}=180 MeV ({similar_to}60% above the Coulomb barrier). The transfer yields are dominated by the ({sup 32}S, {sup 33}S) and ({sup 32}S, {sup 31}P) reactions which account for about 50% of the total quasielastic transfer strength. The transfer probabilities show an exponential decrease with increasing distance of closest approach. The measured decay constants are smaller than the binding-energy derived decay constants. The observed enhancements of the transfer probabilities for the simplest single-step transfer reactions (involving the transfer of up to two nucleons) can be understood quantitatively in terms of quantum diffraction.

A focal plane detector system has been developed for the Rochester Recoil Mass Spectrometer. It consists of a parallel grid avalanche counter (PGAC) backed by an ionization counter (IC). The PGAC is used to obtain the horizontal and vertical position of the incident particles and also to provide a fast timing signal. The PGAC has an active area of 5.1 cm x 5.1 cm. The IC consists of three charge collecting anodes (2.0 cm, 6.2 cm, 21.6 cm long) and provides nuclear charge identification and a total energy measurement. Both the PGAC and the IC are filled with isobutane as the counter gas. The intrinsic position resolution of the PGAC was determined to be 0.9 mm (FWHM). The IC is able to resolve neighboring nuclear charges for light ions with energies as low as 0.7 MeV/u. The nuclear charge resolution of the IC for heavy ions with IC energies below 0.7 MeV/u was found to be 1.3 e (FWHM).

A segmented focal plane detector has been used to study the breakup of 87 MeV $^{11}\mathrm{B}$ ions incident on a $^{12}\mathrm{C}$ target into $^{4}\mathrm{He}$ and $^{7}\mathrm{Li}$ fragments at relative energies between 0 and 4 MeV. The relative energy spectra are dominated by sequential breakup of the 9.28 MeV, 10.26+10.33 MeV, and 10.60 MeV excited states in $^{11}\mathrm{B}$. The measured breakup yields decrease with increasing center-of-mass scattering angle, consistent with predictions made using single-step inelastic distorted wave Born approximation calculations. Applications of this technique to study the breakup of $^{16}\mathrm{O}$ at low relative energies will be discussed.

A segmented focal plane detector for an Enge split-pole spectrograph has been developed for the study of breakup reactions at very low relative energies. It consists of a 61 cm long segmented position-sensitive parallel plate avalanche counter backed by a large Bragg curve detector. A segmented plastic scintillator is mounted behind the anode of the Bragg curve detector and is used for particle identification of low-ionizing particles. The dead space between the two sections of the focal plane detector is 2.5 mm. The intrinsic position resolution of the detector is 1 mm. The intrinsic energy resolution depends on the energy of the incident ion and can be as good as 0.55%. The nuclear charge and mass resolutions are 0.3 e and 0.3 u, respectively.

Objective—To assess the accuracy and validity of three points used in the cephalometric assessment of autorotation in orthognathic surgery. Design—A retrospective study of 15 cases of maxillary surgery. Setting—A postgraduate dental hospital in London. Subject—Fifteen well-documented cases of maxillary surgery with mandibular autorotation, treated by a single surgical, team were examined. Cephalometric surgical predictions were prepared, using the planned surgical movements, incorporating three different points advocated as centres of mandibular autorotation, for each case. These predictions were compared with the results achieved at surgery. Main outcome measures—The discrepancy between the predictions and the surgical result in each case was measured and subjected to statistical analysis. The method error was assessed and considered with the measured discrepancy. Results—Individual variation was seen, both between the individual landmarks and the individual cases studied. The discrepancies measured were broadly similar for each of the centres of autorotation. Statistical analysis failed to show any significant differences between the points studied. Conclusion—All 3 points of autorotation examined will approximate mandibular autorotation following maxillary surgery and all can be considered equally valid.

This study investigated the accuracy with which the planned surgical change could be achieved during orthognathic surgery, based upon the retrospective cephalometric analysis of 62 patients who received correction of dentofacial deformity. It is concluded that, despite individual variation, no statistically significant difference could be demonstrated between the orthognathic prediction and the surgical outcome. This supports both the use of orthognathic profile planning and the surgeon's ability to follow the plan.