A counter system for natural C14 measurement
- Resource Type
- Authors
- C.Y. Fan; Hain Oona
- Source
- Nuclear Instruments and Methods. 143:391-397
- Subject
- Physics
Background subtraction
Physics::Instrumentation and Detectors
business.industry
Detector
Proportional counter
General Medicine
Scintillator
Coincidence
Nuclear physics
Optics
Scintillation counter
Pulse height analyzer
Counter system
business
- Language
- ISSN
- 0029-554X
Two proportional counters made of plastic scintillator were constructed for measuring the C14 contents in dated tree rings. One is for background and the other for specimen. CH4 at 1 atm pressure was used as the counter gas; each counter has an active volume ∼5.51. The wall, being scintillator, serves as a 4π anti-coincidence shell for rejection of natural radioactivity in the material housing the proportional counter and penetrating cosmic ray muons. The outputs of the proportional counters which are in anticoincidence with the scintillation counter were recorded in a pulse height analyzer. After background subtraction, it yields the beta-decay spectrum of carbon-14 in the methane filled proportional counter. Simultaneously, the outputs which are in coincidence with the scintillation counter were also recorded as a monitor of the operational characteristics of the detector systems. The problems inherent with pulse height analyzers and the use of scintillators are discussed and evaluated.