Studies of relative gain and timing response of fine-mesh photomultiplier tubes in high magnetic fields

We investigated the use of Hamamatsu fine-mesh photomultiplier tube assemblies H6152-70 and H6614-70 with regards to their gain and timing resolution in magnetic fields up to 1.9 T. Our results show that the H6614-70 assembly can operate reliably in magnetic fields exceeding 1.5 T, while preserving a reasonable timing resolution even with a gain reduction of a factor of approximately 100. The reduction of the relative gain of the H6152-70 is similar to the H6614-70s near 1.5 T, but its timing resolution worsens considerably at this high field.