Research in nuclear physics at low and intermediate energies, neutrinos and x rays: Final report, May 1980--August 1987
During the past year the research in our West Bridge Laboratory at Caltech has continued to focus on studies of neutrino properties, particularly neutrino mass. To this end the nuclear double beta decay has been exploited and several experiments have been carried out. Upon completion of a series of comprehensive studies of backgrounds and radioactive impurities in various materials conducted with a 90 cm/sup 2/ Ge detector in our Gotthard tunnel laboratory, a large 8 crystal Ge detector array with its cryostat, copper and lead shielding, and data acquisition computer has been installed in the Gotthard tunnel and is now operating well with the anticipated low background. Sensitive limits for two-neutrino and neutrinoless decay, as well as for majoron emission have already been obtained. The latter results rule out a recently published claim. The design and construction of the xenon time projection chamber has been completed. The TPC now operated with an active volume of 206 liters of xenon gas 5 atm. At the present time electron and muon tracks are being recorded and analyzed using a computer based pattern recognition scheme. A double beta decay event is recognized by a contiguous track beginning and ending with a high ionization density ''blob''. At the same time, theoretical nuclear structure calculations have been conducted to help evaluate the rates of the two-neutrino and neutrinoless processes in various double beta decay candidates, including the nuclei /sup 76/Ge and /sup 136/Xe. To further explore new techniques capable of identifying double beta decay in high density targets, extensive studies of electron-ion pair recombination in liquid argon and liquid xenon have been conducted, leading to several novel concepts for the creation of the electron track and the observed energy resolution.
- Research Organization:
- California Institute of Technology (CalTech), Pasadena, CA (United States)
- DOE Contract Number:
- AS03-81ER40002
- OSTI ID:
- 5896859
- Report Number(s):
- DOE/ER/40002-T1; ON: DE89012698
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DOUBLE BETA DECAY
NEUTRINOS
NUCLEAR PHYSICS
RESEARCH PROGRAMS
CALIFORNIUM 252
COMPOUND NUCLEI
DETECTION
ELECTRON CAPTURE
GERMANIUM 76
NEUTRINO OSCILLATION
OXYGEN ISOTOPES
PROGRESS REPORT
REST MASS
SPONTANEOUS FISSION
T INVARIANCE
TERBIUM 158
TIME PROJECTION CHAMBERS
XENON 136
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BETA DECAY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY
BETA-MINUS DECAY RADIOISOTOPES
CALIFORNIUM ISOTOPES
CAPTURE
DECAY
DOCUMENT TYPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTARY PARTICLES
EVEN-EVEN NUCLEI
FERMIONS
FISSION
GERMANIUM ISOTOPES
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
INVARIANCE PRINCIPLES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LEPTONS
MASS
MASSLESS PARTICLES
NUCLEAR DECAY
NUCLEAR REACTIONS
NUCLEI
ODD-ODD NUCLEI
PHYSICS
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SECONDS LIVING RADIOISOTOPES
STABLE ISOTOPES
TERBIUM ISOTOPES
XENON ISOTOPES
YEARS LIVING RADIOISOTOPES
651000* - Nuclear Physics
645100 - High Energy Physics- Particle Interactions & Properties-Experimental