PROPERTIES OF THE $sup 12$C($gamma$, 3$alpha$) REACTION BELOW 21.5 Mev

Journal Article · Wed Jan 01 04:00:00 EST 1964 · Nuclear Physics (Netherlands) Divided into Nucl. Phys. A and Nucl. Phys. B

DOI:https://doi.org/10.1016/0029-5582(64)90229-9· OSTI ID:4025054

Toms, M E

The cross section for the photodisirtegration of /sup 12/C yielding alpha particles has been measured by studying 768 everts in nuclear emulsions exposed to 21.5 Mev bremsstrahlung filtered by 86.2 cm of graphite or by 41.9 cm of aluminium. The value of the cross section integrated up to 20.5 Mev is 0.82 plus or minus 0.03 Mev. mb. The shape of the cross section indicates resonances and suggests six energy regions for study. Of the total events, 103 could be attributed to breakup via the ground state of /sup 8/Be and 557 to breakup via the first excited state of /sup 8/Be. The cross section for the reraaining 108 events, not definitely attributable to breakup via etther /sup 8/Be state, does not resemble the cross section for either the ground state or the first excited state events. The angular distribution of the first alpha particle with respect to the photon for the 77 ground state events produced by /sup 12/C excitation of less than 14.3 Mev indicates that both E2 and E1 interactions are taking place. The modes of interaction which gave the predicted alpha energy distributions in the best agreemert with the data for the first excited state events by /sup 12/C excitation regions are 0.25 M1 and 0.75 E1 for 12.2-14.2 Mev, 0.8 E1 and 0.2 E2 for 14.3-16.3 Mev, 0.4 E2 and 0.6 M1 for all E1 for 19.6-21.8 Mev. (auth)

• Research Organization: Naval Research Lab., Washington, D.C.
• NSA Number: NSA-18-019008
• OSTI ID: 4025054
• Journal Information: Nuclear Physics (Netherlands) Divided into Nucl. Phys. A and Nucl. Phys. B, Journal Name: Nuclear Physics (Netherlands) Divided into Nucl. Phys. A and Nucl. Phys. B Vol. Vol: 50; ISSN NUPHA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALPHA PARTICLES
ALUMINUM
ANGULAR DISTRIBUTION
BERYLLIUM 8
BREMSSTRAHLUNG
CARBON 12
CONFIGURATION
CROSS SECTIONS
DISTRIBUTION
ENERGY
ENERGY LEVELS
ENERGY RANGE
EXCITATION
FILTERS
GAMMA RADIATION
GRAPHITE
INTERACTIONS
MEASURED VALUES
MEV RANGE
NUCLEAR EMULSIONS
NUCLEAR REACTIONS
PHOTOFISSION
PHYSICS
RESONANCE