Crosstalk between Twinax cables

Run 12523. Only one T0P0 versus only one T0N5.

(06/02 14:33, A. Sukhanov) All TC signals disabled by pulling out cables from F11. The TC is connected to T0N5 only. The free running generator 1 MHz is connected to T0P0. TC is set to 80/40 to have less pulses outside of TDC range, with this setting there are only 2 pulses in the high resolution range.

Signals:

T0P0 is connected to FB TDC17[0]. Free running generator 1MHz.

T0N is connected to FB TDC17[1] and VME VTDC0[1].

T0P is connected to FB TDC17[2] and VME VTDC0[0].

T0N5 is connected to FB TDC17[3]. Time Calibrator.

T0P0 vs T0N5 using FASTBUS TDC.

Draw("TDC17[2]:TDC17[1]>>hT0FP_N","","colz")

The zigzag at Y=500: effect of the trailing edge of the generator pulse

The bump at Y=1500: effect of the leading edge of the generator pulse

Run 12517. All TC enabled.

Draw("TDC17[2]:TDC17[1]>>hT0FP_N","","colz")

The effect does not depend how many neighbors are fired.

Draw("TDC17[2]>>hFT0P0","1550<TDC17[1]&&TDC17[1]<1650")

Peak at 1633: crosstalk from the leading edge of the TC pulse

A structure at 2300: crosstalk from the trailing edge of the TC pulse

Draw("TDC17[0]:TDC17[3]>>hT0FP_N","","colz")

Draw("VTDC0[0]:VTDC0[1]>>hVT0P_N","1550<TDC17[1]&&TDC17[1]<1650

Draw("TDC17[1]:VTDC0[1]>>hFVT0N","1550<TDC17[1]&&TDC17[1]<1650

Draw("TDC17[2]:VTDC0[0]>>hF_VT0P","1550<TDC17[1]&&TDC17[1]<1650

The same, exploded. The vertical distortion is about 20 counts.

Run 12524. Twinax directly connected to TDC17

The twinax is connected to TDC17 using 2m of separate twisted pairs.

The shield is not connected.

The generator is 4 MHz.

The T0P0 is moved from TDC17[0] to TDC17[4] due to 40% of fails in ch 0.

T0P0. Looks reasonable

chain.Draw("TDC17[2]:TDC17[1]>>hFT0P_N","","colz")

Run 12525. chain.Draw("TDC17[2]:TDC17[1]>>hFT0P_N","","colz")

There is no crosstalk in pure twinax.

Why it differs from TDC[4]?

Run 12526.

T0P0 and T0N5 are terminated at the ECL/NIM

Looks OK now.

chain.Draw("TDC17[2]:TDC17[1]>>hFT0P_N","","colz")

First TC position

chain.Draw("TDC17[2]:TDC17[1]>>hFT0P_N","","colz")

Second TC Position

Run 12528. Added 2 meters of SpectraStrip

chain.Draw("TDC17[2]:TDC17[1]>>hFT0P_N","","colz")

chain.Draw("TDC17[2]:TDC17[1]>>hFT0P_N","","colz")