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Current techniques used to produce carbon micro-ribbon targets 5 μm wide×3.7–4.5 μg/cm 2 ×25-mm long will be described. Developmental emphasis was to provide nearly identical micro-ribbons with the minimum number of atoms per unit of length, and to position them within ±0.5 mm of the desired location on C-shaped frames. The foil strip targets to be described were 200–600 μm wide×3.7–4.5 μg/cm 2 ×51 mm long. These were produced from 25-mm-wide carbon film deposits that were scribed using a jig prior to dissolving the betaine/sucrose release agent under ethanol. Both types of targets required methods and devices that differed significantly from those reported previously for substrate texturing, masking, vacuum deposition, releasing from the substrate, and mounting. Sets of 12–24 of the targets have been made for the 2006 run period at BNL.

Red 31 P targets of 2.6 and 2.9 mg/cm2±0.1 mg/cm2 with 1-cm×2-cm side dimensions were prepared for a nuclear mass measurement which required good thickness uniformity. The thinner target, with 50 μg/cm2 of gold flashed on both surfaces, withstood a 173-MeV α beam of 175 nA for 18 h. Adaptations will be described for an Indiana University Cyclotron Facility air-settling method used to distribute phosphorus powder, as well as the methods developed for subsequent pressing, roll thinning, and dry release to obtain self-supporting targets. An envelope of gold foil, in contact with the phosphorus during each step, was instrumental in the process.

For a neutron-lifetime experiment at the National Institute of Standards and Technology (NIST), an alloy of 6Li and Mg was prepared as a disk 2.8 mm thick and 37.9 mm in diameter. Three-plus grams of a homogeneous alloy with a 6Li content approaching 74 at%, a very low hydrogen content and a low oxygen content were required. A sealed stainless-steel crucible was used for the alloying, in consideration of the chemical activities and vapor pressures of Li and Mg at the alloy-formation temperature (≥925 K). This report includes design details of the weld-sealed crucible, adaptations made to a radio-frequency (RF) induction furnance and the process used to prepare 4.5 g of the alloy, recover the alloy from the crucible and shape it into a disk. For ten months, the disk was stored successfully by continous vacuum pumping at 1.3 kPa. Back-scattered gamma rays revealed the alloy had acceptably low levels of hydrogen and oxygen. No other contaminants were detected.

Immersion coating, spray coating, stretching, and roll-reduction methods have been explored in work to produce pinhole-free films of Teflon that are 5 cm × 30 cm in area and less than 500 μg/cm 2 thick. A method to produce these films by rolling thicker, commerically available films will be described. The defining characteristics and limitations encountered with each of the other preparation methods also are presented. Four of the self-supporting Teflon films form the walls of an open-ended cell used to increase the density of a polarized-hydrogen target [M.A. Ross et al., Nucl. Instr. and Meth. A 344 (1994) 307; W.A. Dezarn et al., these Proceedings (17th World Conf. of the INTDS, Bloomington, IN, USA, 1994) Nucl. Instr. and Meth. A 362 (1995) 36]. At a wall thickness of 500 μg/cm 2 , roughly half the thickness of commerically available film, detection of recoil protons became possible.

The use of thin fibers as internal targets for nuclear physics experiments in storage rings is discussed. We have measured the lifetime and the energy spread of stored, electron-cooled beams in the presence of an internal carbon fiber target. Measurements have been carried out in the Indiana Cooler with proton beams between 100 MeV and 300 MeV. The effect of the inhomogeneous fiber target on the beam is the same as that of a homogeneous gas target of equivalent thickness within the accuracy of the measurement. The measurements are compared with a Monte Carlo simulation of the stored beam. It is demonstrated that charging of the fiber target can significantly affect the lifetime and energy spread of the stored beam.

The use of 5–15 μg/cm 2 films of vacuum-evaporated carbon as targets and stripper foils in the IUCF cooler ring requires compliance with the characteristics of the ring. One way to circumvent the upper limit in target thickness of 10 15 nuclei/cm 2 (less than 100 ng/cm 2 ) for stationary targets is to move a somewhat thicker ribbon quickly through the beam. Our current methods for fabricating, handling, and mounting carbon micro-ribbons are described. Stripping-injection of 90 MeV H 2 + beam from the cyclotron into the cooler is accomplished using 5–15 μg/cm 2 stationary carbon foils. The requirement that these foils be mounted on a “C”-shaped frame with an open side of 31 mm, proved surprisingly easy to fulfill. A technique will be described for producing single-layer stripper foils which have a relatively straight edge that is unsupported across one side.

A natural-carbon analog of fluffy, intractable 14C powder was produced. With it, a method was developed to produce a pressed disk of 14C of 12.7-mg/cm2 thickness and 1.27-cm diameter, bound with 2.1 wt.% of adhesive. Aluminized Mylar cover foils and a fritted-disc filter were used to contain the target for ( p , p′) experiments. Reduction of 71Ga2O3 to the metal was accomplished with an efficiency of 94.3% in a small electroplating cell. Magnesium was chosen as the companion element because 50 at.% could be tolerated in the (p, n) experiment, and GaMg has a melting point of 646 K. A 1.27-cm diameter target, supported at the edge by a Mg foil, was produced in several simple steps. Directly rollable 66,67Zn foils were obtained from an electroplating cell with a Pt screen anode and a highly polished tungsten-carbide cathode. Plating times of 3 h provided metal-recovery efficiencies ranging from 94.2 to 96.5%. The as-deposited foils had many holes but were hole-free and shiny after reduction of 25% by pack rolling.