[PRad] [Revised Logentry] Dynode signal check for noise issue

[liye at jlab.org]

Logentry Text:
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In order to reduce the noise level of Dynode total sum of HyCal, I checked Dynode noise .
1. The noise level for vme crate is about 30mV .
2. The noise level for output of UVA module is about 10mV , (detailed data as follow:) 
    Dynode Group       noise level (mV)            
            G11 ~~ 4.8                                    G1~~ 6.8                                 W33~~ 6.8                                  G5~~6.0                                  G15~~6.8
            G16 ~~5.2                                    G6~~ 7.2                                 W3 ~~12.4                                 G10~~ 5.6                                  G20~~ 6.4  
            G21~~5.2                                    W31 ~~ 8.4                                 W9 ~~ 10.8                                 W30 ~~10.2                                G25 ~~ 6.4
            W7 ~~12.4                                   W19~~ 10.4                               W15 ~~ 7.6                                  W6~~ 9.6                                  W12~~75.0
            W25 ~~ 10.8                                  W13  ~~ 8.8                                W21~~7.6                                  W18~~ 9.6                                  G24  ~~7.2
            G2 ~~ 5.6                                    W1~~ 10.8                               W27 ~~ 7.2                                 W24~~ 11.2                                 G4~~11.2
            G22~~6.4                                   W14 ~~10.8                               G23~~29                                  W36 ~~11.2                                W23 ~~ 11.2
            W32~~10.4                                  W8  ~~ 11.6                                G3~~12                                  W5  ~~ 8.8                                  W29~~7.4
            W26 ~~13.6                                  W2 ~~ 11.2                                W28 ~~ 35                                  W11~~ 20.0                                W35~~11.2
            W20 ~~ 13.6                                W22 ~~ 12.8                                W17 ~~12.4                                 W34~~ 44.8
          W16 ~~ 25.2                                W4~~11.2                                       W10 ~~ 23.0                               


3. Few bad groups were found , G23( 29mv) ,G3(75mv) ,W28(35mv), W16(25mv),W10(23mv), W11(20mv),W12(75mv),W34(45mv).
    For those "bad" modules , checked all the channels and found the noise level determind by the noise level of channels. 
    for G3 group -- channel G136 was bad , large noise (90mV) with 2KHz appeared, for W12 group channel W335 was bad ~ 70mV and most of channels were bad.
    havent got chance to check group W34,will do.

conclusion :  noise level of Dynode total sum signal came from the individual channel (most likely from divider), UVA module and vme crate have small effect on this noise issue.



           

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