1 / 1

Experimental set-up for on the bench tests

s = 40ps. s = 37ps. a. s = 39ps. s = 38ps. Timing and Cross-Talk Properties of BURLE /Photonis Multi-Channel MCP PMTs S.Korpar a , b , I. Adachi c , R. Dolenec b , P. Križan d ,a , R . Pestotnik b , A . Stanovnik d ,a

satya
Download Presentation

Experimental set-up for on the bench tests

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. s = 40ps s = 37ps a s = 39ps s = 38ps Timing and Cross-Talk Properties of BURLE/Photonis Multi-Channel MCP PMTs S.Korpara,b, I. Adachic, R.Dolenecb, P.Križand,a, R.Pestotnikb, A. Stanovnikd,a aUniversity of Maribor, Slovenia, bJožef Stefan Institute, Ljubljana, Slovenia, cKEK, Tsukuba, Japan, dUniversity of Ljubljana, Slovenia ALS PiLas controller TDC Kaizu works KC3781A discriminator Philips model 806 NIM amplifier ORTEC FTA820A signal splitter passive 3-way CAMAC QDC CAEN V965 PC LabWindows CVI Abstract VME Modeling of processes in the MCP PMT We report on on-the-bench studies of the two types of BURLE multianode micro-channel plate(MCP) PMTs, one with 64 channels and other with 4 channels, both with 10mmpores. A possible applications of this tubes are RICH and time-of-flightcounters. We haveinvestigated the timing properties of the tubes and studied various cross-talks and their influenceon the timing and spatial resolution. We have also performed tests in magnetic field up to 1.5 T. Parameters used: - cathode to MCP potential difference U = 200 V - photocathode to MCP distance L = 6 mm - photoelectron initial energy E0 = 1 eV g Photo-electron: • d0,max~0.8 mm • t0 ~ 1.4 ns • Δt0 ~ 100 ps Motivation Photo-electron range, projected g Backscattering: • d1,max=2L=12 mm • t1,max ~ 2.8 ns b Distributions assuming that back-scattering by angle b is uniform over the solid angle. Charge sharing Photo-electron travel time ~ 12mm ~ 2.8ns Timing TDC distribution has three contributions: - prompt signal ~ 70% - short delay ~ 20% - uniform distribution ~ 10% back-scattering • Present study: • measure detailed timing properties and cross-talk, • determine their influence on the position resolution and time resolution. 70% 20% Experimental set-up for on the bench tests BURLE 85011 MCP-PMT: - multi-anode PMT with two MCP steps - 2x2(8x8) anode pads - 10 mm pores - bialkali photocathode - gain ~ 0.6 x 106 - collection efficiency ~ 60% Outside dark box: - PiLas diode laser system EIG1000D (ALS) - 404 nm and 635 nm laser heads (ALS) - neutral density filters (0.3%, 12.5%, 25%) - optical fiber coupler (focusing) - optical fiber (single mode,~4mm core) Signal processing: - laser rate 2kHz (~DAQ rate) - amplifier: 350MHz (<1ns rise time) - discriminator: leading edge, 300MHz - TDC: 25ps LSB(s~11ps) - QDC: dual range 800pC, 200pC - HV 2400V Inside dark box mounted on 3D stage: - optical fiber coupler (expanding) - semitransparent plate - reference PMT (Hamamatsu H5783P) - focusing lens (spot size s ~ 10mm) 10% Time resolution of the main peak is dominated by the photo-electron time spread (26ps rms, estimated from the model); other contributions are laser timing (15ps rms) and electronics (12ps rms). Time-walk corrected TDC distributions of all four channels of 2x2 MCP PMT. For the Belle particle identification system upgrade, a proximity focusing RICH detector withaerogel as radiator is being considered. One of candidates for the detector of Cherenkov photonsis a microchannel plate PMT. With its excellent timing properties, such a counter could serve inaddition as a time-of-flight counter. A prototype of this novel device using BURLE 85011 64-anode, microchannel plate PMT with 25mmpores, was tested in the test beam at KEK. Excellent performance ofthis counter could be demonstrated (left). In particular, a good separation of pions and protonswas observed in the test beam data with a time-of-flight resolution of 35ps (right). Timing with a signal from the second MCP stage If a charged particle passes the PMT window, ~10 Cherenkov photons are detected in the MCP PMT; they are distributed over several anode channels. Idea: read timing for the whole device from a single channel (second MCP stage), while 64 anode channels are used for position measurement Single anode MCP second stage output s < 40ps Timing resolution as a function of light intensity Uniformity of response at B=0T and B=1.5T Scans across a 64 channel PMT without (top) and with magnetic field (bottom). Surface response of PMTs is fairly uniform. Multiple counting is observed at pad boundariesdue to charge sharing. B = 0 T, HV = 2400 V Tests in magnetic field 1 2 • Measurements of gain, uniformity of response snd cross talk • Magnet at KEK with B field up to 1.5 T • Light source - laser: • wavelength 439 nm • spot size < 0.5 mm • pulse timing 90 ps (FWHM) 1 2 B = 1.5 T, HV = 2500 V Gain in magnetic field Gain as a function of magnetic field for different operation voltages and as a function of aplied voltage for different magnetic fields. . . 2 x 12mm = range of back-scattered photo-electrons Number of detected hits on individual channels as a function of light spot position. Slice of 2D distribution shows a uniform response withinthe pads, and the long range cross talk due to photoelectron back-scattering and photon reflection. In the presence of magnetic field, charge sharing and cross talk due to long range photoelectron back-scattering are considerably reduced.

More Related