PA-PRO-2014-022

Publication title: 

Improved lifetime of microchannel-plate PMTs

Publication author: 

A. Lehmann et al. (PANDA Cherenkov Group)

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PDF icon PA-PRO-2014-022.pdf

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Papers: 

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Publication date: 

Sunday, 13 April, 2014

Publication abstract: 

The charged particle identification at the PANDA experiment will be mainly performed with DIRC detectors. Because of their advantageous properties the preferred photon sensors are MCP-PMTs. However, until recently these devices showed serious aging problems which resulted in a diminishing quantum efficiency (QE) of the photo cathode. By applying innovative countermeasures against the aging causes, the manufacturers recently succeeded in drastically improving the lifetime of MCP-PMTs. Especially the application of an ALD coating technique to seal the material of the micro-channels proves very powerful and results in a lifetime of ~6 C/cm2 integrated anode charge without a substantial QE degradation for the latest PHOTONIS XP85112. This paper will present a comparative measurement of the lifetime of several older and recent MCP-PMTs demonstrating this progress.