An optical readout TPC (O-TPC) for studies in nuclear astrophysics with gamma-ray beams at HI gamma S

作者：Gai M^*; Ahmed M W; Stave S C; Zimmerman W R; Breskin A; Bromberger B; Chechik R; Dangendorf V; Delbar Th; France R H III; Henshaw S S; Kading T J; Martel P P; McDonald J E R; Seo P N; Tittelmeier K; Weller H R; Young A H

来源：Journal of Instrumentation, 2010, 5: P12004.

DOI：10.1088/1748-0221/5/12/P12004

• Gaseous imaging and tracking detectors
• Time Projection Chambers (TPC)
• Gaseous detectors

We report on the construction, tests, calibrations and commissioning of an Optical Readout Time Projection Chamber (O-TPC) detector operating with a CO(2)(80%) + N(2)(20%) gas mixture at 100 and 150 Torr. It was designed to measure the cross sections of several key nuclear reactions involved in stellar evolution. In particular, a study of the rate of formation of oxygen and carbon during the process of helium burning will be performed by exposing the chamber gas to intense nearly mono-energetic gamma-ray beams at the High Intensity Gamma Source (HI gamma S) facility. The O-TPC has a sensitive target-drift volume of 30x30x21 cm(3). Ionization electrons drift towards a double parallel-grid avalanche multiplier, yielding charge multiplication and light emission. Avalanche-induced photons from N(2) emission are collected, intensified and recorded with a Charge Coupled Device (CCD) camera, providing two-dimensional track images. The event's time projection (third coordinate) and the deposited energy are recorded by photomultipliers and by the TPC charge-signal, respectively. A dedicated VME-based data acquisition system and associated data analysis tools were developed to record and analyze these data.
The O-TPC has been tested and calibrated with 3.183MeV alpha-particles emitted by a (148)Gd source placed within its volume with a measured energy resolution of 3.0%. Tracks of alpha and (12)C particles from the dissociation of (16)O and of three alpha-particles from the dissociation of (12)C have been measured during initial in-beam test experiments performed at the HI g S facility at Duke University. The full detection system and its performance are described and the results of the preliminary in-beam test experiments are reported.

• 出版日期2010-12