REACTION STUDIES WITH FAST NEUTRONS

Technical Report · Fri Nov 01 04:00:00 EST 1963

DOI:https://doi.org/10.2172/4151122· OSTI ID:4151122

Maxson, D R

The modified accelerator performed well at voltages up to 200 kv, and construction of a 350-kv acceleration tube was initiated. An all solid state telescope was completed and a (dE/dx x E) pulse multiplier was almost finished. These instruments will be used with a new analyzer to permit simultaneous recording of (n,p), (n,d), and (n,t) spectra. An analysis of previous data on LiT/sup 7/d, alpha ) He/sup 5*/ yields alpha + n showed that the first He/sup 5/ excited state is at 2.6 plus or minus 0.4 Mev with a width of 4.0 plus or minus 1.0 Mev. The intensity of the excited state relative to that of the ground state was found to be 1.45 plus or minus 0.50. Preliminary angular distributions for the N/sup 14/(n, alpha )B/sup 11/ and O/sup 16/(n, alpha )C/sup 13/ reactions were dobtained Modifications were made to the counters for these experiments, and electronic equipment asociated with the counters and detectors was constructed. (D.C.W.) Aluminum targets evaporated under a variety of conditions all showed a Lewis peak on the thick-target gamma -ray yield curves over the Al/sup 27/(p, gamma )Si resonance reaction at 992 kev. The peaks of all targets prepared at pressures below 4 x 10/sup -7/ mm Hg rose above the plateau to a height of about 10% of the plateau yield. Targets prepared at higher pressures showed smaller peaks. Thick-target yield curves from the Ni/sup 58/(p, gamma )Cu/sup 59/ resonance reaction at 1424 kev showed a Lewis peak which was about 23% above the plateau yield. Results indicate that nickel targets are much less susceptible to contamination than aluminum. Yield curves were calculated using an improved collision spectrum that takes into account the electron shells of the atom. These calculated curves fit the experimental data much better than previous calculations that treated the electrons in the target as free. Results from these calculations indicate that the point corresponding to one-half the plateau yield, lies about 120 ev below the resonance energy for aluminum and 125 ev below for nickel. Results also indicate that past methods for experimentally determining energy resolution from thick-target yield curves are in error. (auth)

• Research Organization: Brown Univ., Providence
• NSA Number: NSA-18-002840
• OSTI ID: 4151122
• Report Number(s): NYO-9766
• Country of Publication: United States
• Language: English

Related Subjects

ACCELERATORS
ALPHA PARTICLES
ANGULAR DISTRIBUTION
BORON 11
CARBON 13
COINCIDENCE METHODS
COUNTERS
CRYSTAL COUNTERS
DEUTERONS
ELECTRIC POTENTIAL
ELECTRONIC EQUIPMENT
ENERGY LEVELS
EXCITATION
FAST NEUTRONS
HELIUM 5
LIFETIME
LITHIUM 7
NEUTRON BEAMS
NITROGEN 14
NUCLEAR REACTIONS
OXYGEN 16
PHYSICS
PROTONS
PULSE ANALYZERS
RECORDING SYSTEMS
SPECTRA
TRITONS