12/01/16      (Attachments 1-8)

FEEs set up as per ELOG entry 136 (15/12/15)

Connected cables as follows:

     - nnaida11 > LH coupler + 45cm ribbon (unshielded)

     - nnaida12 > no load (no waveforms from this card)

     - nnaida13 > LH coupler + 45cm ribbon (unshielded) + RH coupler

     - nnaida14 > LH coupler

Peak widths (ch):         <all with shaping time of 8us and heavy duty Cu braid between test inputs on each adapter card>

                     nnaida11  |  nnaida12  | nnaida13  |  nnaida14

     1.4.L   |        392       |       14.7       |      250       |      34.3 

     1.6.L   |       300        |       13.6       |      150       |      23.1

     1.8.L   |       290        |       13.0       |       123      |      16.8

    1.10.L  |       309        |       13.2       |       129      |  no output

     > widths greater than expected

     > thought it could possibly be due to pickup of external noise in the room so added Cu tape as shielding to cable connected to nnaida13 with drain wire connected to CU braid on pulser input

     > reduced peak with in nnaida13 to ~160ch

     > connecting far end of Cu shielding via a Cu braid to main Cu braid reduces this to ~130ch

     > connecting Cu shielding on RH coupler to main ribbon cable shielding with thin braid reduced this further to ~110ch

For nnaida13, see double peaking of pulser peak with all shaping times up to 2us. At 4us, see single peak of width ~160ch. At 8us, see single peak of width ~110ch.

13/01/16      (Attachments 9-20)

Set up system as yesterday.

With shaping time of 2us, nnaida13 does not show Gaussian peaks. Some peaks are double, others just single non-Gaussian peaks.

Yesterday peak-to-peak difference was ~150ch

    - added tin foil to loose coupler end and over connection between ribbon cable and RH coupler, as it was suspected it could be pickup of external noise

    - @ 2us shaping time, double peaks still present with p-2-p difference of ~130ch

    - clipped foil firmly to Cu shielding tape  >  no difference.

In nnaida14, see single roughly Gaussian peak of width ~15ch.

In nnaida11, see single peaks of widths ~250ch. At 8us this reduces to ~180ch.

Connecting the Lk7 jumper for nnaida13 produces no difference.

Added full LH coupler + 45cm ribbon + RH coupler to all nnaida, with full shielding > no improvement.

Connected all to detector and saw no improvements, in fact increased noise in nnaida13 dramatically (see waveforms)

See low frequency wave in waveforms, will work next week to try remove this as this could be what is causing the double peaking and hiding the true capabilities of the cables.