1 Veto Wall Test Hyupwoo Lee MINERvA/Jupiter Group Meeting June 20, 2007

2 Introduction Purpose of veto wall : To exclude events which is from impurities of neutrino beam. How? : Using a set of big scintillator panels with PMT forward and backward(?) of main detector. My job : Test panels and PMTs and figure out the characteristics of its signals. Since now : Examine the signals through the waveform taken by oscilloscope.

3 Contents Position Test : Examine the changing of signals with different hit position Timing test : Time characteristics of signal – start position of signal in time domain Cable length test : observe the signals with different signal cable length

4 Position Test Take data with only left hand side PMT Sections : row position - ½ of A and ½ of B, column position - 2, 4, 6, 8, 10, 12, 14 Averaged signal waveform of 32 events Use 2 small panels for trigger signal : same for all the other test

5 Position Test – result 1 - Signal size decreases when the distance between PMT and hit position increases - Signal seems to be delayed with the distance

6 Position Test – result 2 - Signal size reaches over than 30pC

7 Timing Test Sections : C02, C08, C14 Single sample event 2 different DAQ method - Taking waveform from scope (25 samples for each section). - Using math func. in scope (~80 samples for each section) 3 different way used for analysis - 10% peak (signal volt) to 10% peak (trigger) : same as scope math func. - 10% of total charge (signal) to 10% peak (trigger) fC (signal) to 10% peak (trigger)

8 Timing Test – result 1 - Standard deviation of timing (signal’s falling edge to trigger’s falling edge) is ~10ns - Signals are delayed by the length between hit position and PMT. - Scope cal. data for C14 is biased by data selection

9 Timing Test – result 2

10 Cable Length Test Sections : C02, C08, C14 Averaged signal waveform of 256 events Signal cable length for big panel varied with 323cm (x1, x2, x3) – using 3 same BNC cables.

11 Cable Length Test – result 1 - As cable goes longer, signals are distorted a little, but it seems OK. - As timing, shifting the signal is roughly matched with cable delay (5.5ns/m). - Roughly small signal (section #C14 – far from PMT) shows the same feature only but amplitude.

12 Cable Length Test – result 2

13 Plan for Future FEB test for veto wall Determine the setup of FEB for veto wall

14 Backup 1 (sample waveform) Timing test C02 sample #3

15 Backup 2 (select event - scope cal.)