A 2 x 2 mm(2) superconducting strip-line detector for high-performance time-of-flight mass spectrometry

We present the fabrication and characterization of the latest generation of superconducting strip-line detectors (SSLD) for application in time-of-flight mass spectrometer (TOF MS) of heavy molecules. The SSLD is realized in the parallel strip-line configuration to achieve a 2 x 2 mm(2) sensitive area. The parallel SSLD is mounted in a TOF MS and tested at 4.2 K under bombardment of lysozyme molecules. The detector exhibits output pulses with rise and fall times of 500 ps and 2.3 ns respectively. We also present measurements of the time evolution during the acquisition of the singly and doubly charged monomers and singly charged dimers peaks in the mass spectrum. We argue that the observed behavior proves that parallel SSLD can perform charge state discrimination. The achievement of a 2 x 2 mm(2) sensitive area with an output pulse rise time in the region of the sub-nanosecond and a fall time of a few nanoseconds is a milestone in the development of superconducting detectors for TOF MS applications because it addresses important issues such as high mass resolution and high-throughput analysis.