=====veto shield station correlated timing=====
The veto shield has 4 independent DAQ stations NE,NW,SE,SW in each geographical corner of the Soudan 2 cavern at Soudan.  Each station has two or three front-end electronics multiplexer (MUX) boards.  The expected relative timing resolution of < 4us for our 1kHz GPS carrier, had been observed as of June 4th 2013 on only one station-mux-combination pair.  The pair which showed the good timing was SE MUX 2, to SW MUX 2.  The correlated timing was confirmed using a 40 Hz pulser which supplied simultaneous pulses to both of the station/mux combinations. The last week in June 2013 was deticated to examining this problem in detail with Kelly Stifter at Soudan, setting up various timing tests.   

Several kinds of tests were used to diagnose the problem, a summary table of the tests is given below. 

^Date^Time^Test^GPS Connection^Station/MUX^Tube^Outcome^Notes^
|6/4/2013|1215 - 1453|long 40Hz pulser|daisy chain|NE1,NW1|P8T166 (NE); P8T156 (NW)|bad|> 1ms width|
|6/4/2013|1516 - 1639|long 40Hz pulser|t-ed|SE2,SW2|P0T11 (SE); P2T19 (SW) |good|< 4us width|
|6/5/2013|1657 - 1356 (6/10)|long 40Hz pulser|t-ed|NE1,NW1|P8T166 (NE); P8T156 (NW)|bad|> 1ms width|
|6/10/2013|1520 - 1333 (6/12)|long 40Hz pulser|t-ed|SE2,NE1|P5T25 (SE); P9T8 (NE)|bad|> 1ms width|
|6/20/2013|0808 - 0814|40Hz pulser cycle|t-ed|NW2,SW2|P30T8 (NW); P2T9 (SW)|bad| off ~5s|
|6/20/2013|1443 - 1444|manual strobe test|t-ed|NWdaq,SW1|P14T10 (SW)|bad| off ~29m|
|6/24/2013|1111 - 1118|40Hz pulser cycle|t-ed|SE1,SW2|P13T14 (SE); P2T15 (SW)|bad| off ~12m|
|6/24/2013|1120 - 1128|40Hz pulser cycle|t-ed|SE2,SW2|P0T16 (SE); P2T15 (SW)|good| < 1us diffs|
|6/24/2013|1314 - 1321|40Hz pulser cycle|t-ed|NW2,NE2|P22T14 (NW); P29T14 (NE)|good| < 1us diffs|
|6/24/2013|1338 - 1346|40Hz pulser cycle|t-ed|SE1,NE2|P13T14 (SE); P29T14 (NE)|bad| off ~18s|
|6/25/2013|1700 - 1706|40Hz long/cycled pulser|t-ed|NW2,NE2|P22T14 (NW); P29T14 (NE)|correctable| NE2 trails 8s|
|6/26/2013|1045 - 1052|40Hz long/cycled pulser|t-ed|SE1,SW2|P13T14 (SE); P2T15 (SW)|correctable| SE1 trails 17.6h|
|6/26/2013|1522 - 0918 (6/27) |0.2Hz pulser strobe test|t-ed|NE|all|bad|not always reset|
|6/27/2013|0929 - 1129|0.2Hz pulser strobe test|t-ed|NW1|all|good|no bad/missed strobes|
|6/27/2013|0929 - 1129|0.2Hz pulser strobe test|t-ed|NW2|all|good|no bad/missed strobes|
|6/27/2013|1141 - 1457|0.2Hz pulser strobe test|t-ed|SE1|all|strange|strobe to 5s not 0s, none missed|
|6/27/2013|1141 - 1457|0.2Hz pulser strobe test|t-ed|SE2|all|strange|strobe to 5s not 0s, none missed|
|6/27/2013|1141 - 1457|0.2Hz pulser strobe test|t-ed|SW1|all|good|no bad/missed strobes|
|6/27/2013|1141 - 1457|0.2Hz pulser strobe test|t-ed|SW1|all|strange|eventually strobe to 5s not 0s, none missed|
|6/27/2013|1505 - 1622|40Hz long/cycled pulser|t-ed|SE1,SW1|P13T14 (SE); P14T14 (SW)|correctable|SW1 trails 9s|
|6/28/2013|0744 - 0856|40Hz long/cycled pulser|t-ed|NW3,NE3|PNMMbotT7 (NW); PNFACEbotT7 (NE)|bad|bad data|
|6/28/2013|0901 - 1011|40Hz long/cycled pulser|t-ed|NW2,NE3|P22T14 (NW); PNFACEbotT7 (NE)|correctable|NW2 trails 13s|
|6/28/2013|1017 - 1132|40Hz long/cycled pulser|t-ed|NE3,SE1|PNFACEbotT7 (NE); P13T14 (SE)|correctable|SE1 trails 168s|
|7/8/2013|0823 - 0941|40Hz long/cycled pulser|t-ed|NE2,NE3|P29T14 (NE); PNFACEbotT7 (NE)|correctable|NE2 trails 64.93 hours|
|7/8/2013|0949 - 1100|40Hz long/cycled pulser|t-ed|NW1,NW2|P22T12 (NW); P30T14 (NW)|good| < 1us diffs|
|7/8/2013|1115 - 1225|40Hz long/cycled pulser|t-ed|NW1,SW1|P22T12 (NW); P14T14 (SW)|correctable|NW1 trails 8s|
|7/8/2013|1239 - 1246|40Hz long/cycled pulser|t-ed|NW2,SW1|P30T14 (NW); P14T14 (SW)|correctable|NW2 trails 2s|