A microchannel plate system for accelerator mass spectrometry measurements

✍ Scribed by C. Cetina; D.L. Knies; K.S. Grabowski; M. Getaneh; S.J. Tumey; R. Raffanti; O.H.W. Siegmund; J.V. Vallerga

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 181 KB
• Volume: 513
• Category: Article
• ISSN: 0168-9002
• DOI: 10.1016/j.nima.2003.08.070

✦ Synopsis

The position-sensitive focal plane detector system for the trace element accelerator mass spectrometer at the US Naval Research Laboratory consists of 12 microchannel plate detector modules. Each module provides a 10 Â 2 cm 2 active area and together they cover 80% of the split-pole spectrograph focal plane. The MCP detects electrons produced when an MeV ion beam passes through a thin carbon foil placed at 45 with respect to the beam. The electric charge is amplified and deposited on a double-delay line anode, with differential timing at the two ends providing horizontal position. Vertical position is evaluated from top-to-bottom charge partitioning. The collected charge is converted to timing signals through specially designed readout electronics based on the MQT300A LeCroy integrated circuit. A 400-mm horizontal resolution was obtained from ion beam generated secondary electrons accelerated to 2.5 keV. A Helmholtz-type coil pair was built for further confining the secondary electrons with a magnetic field.