Power supply cable

Charge injection3 channels readout

(external cables to the scope)

3 channels readout

(internal cables)

Set up for reading two cards

3 channels readout Charge Injection

Testing one card at a time

Reading one card

3 channels connected

Output signals are reasonable

The quality of the output signal improves when the grounds of the input and output cables were connected inside the box

Same for both cards

Grounds of input and output cables are connected

Single channel - Single card (2)

-30

-25

-20

-15

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-5

0

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Single channel Single Card (1)

-30

-25

-20

-15

-10

-5

0

5

10

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Testing one card at a time with one channel connected – signal recorded from main channel

Long tail

Ringing/oscillations in the tail

Single channel Single card (1) ground

-120

-100

-80

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-20

0

20

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Single channel single card (2)

-120

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0

20

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Long tail, oscillations reduced when the grounds of the input and output inside the box are connected

Gain is also increased

Testing one card at a time with one channel connected – signal recorded main channel

Two channels Single Card (1)

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0

20

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Two channels single card (2)

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0

20

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Testing one card at a time with two channels connected – signals recorded from main channel

3 channels single card (1)

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-80

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0

20

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

3 channels single card (2)

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0

20

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

Testing one card at a time with three channels connected – signal recorded from main channel

3 channels 2 cards (1)

-140

-120

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-40

-20

0

20

40

-10 -8 -6 -4 -2 0 2 4 6 8 10

Time (ns)

mV

3 channels 2 cards (2)

-50

-40

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-20

-10

0

10

20

-60 -40 -20 0 20 40 60

Time (ns)

mV

Testing one card at a time with three channels connected – signal recorded from main channel

Reasonable signal recorded from bottom card (card 1), but with bad oscillations

Very bad oscillations on top card (card 2)

Signals in the two cards do not behave in the same manner

Summary of current status

Can read one channel from one card

Signal quality improves when the grounds of cables for the input and output inside the shielding box were connected

With this configuration, signals in the main channel are reasonable in terms of time response and gain, even when the neighbour channels are connected

When both cards are connected, signals from one card has a long tail and the other with significant oscillations.

Work to do:

To investigate the problem when two cards are connectedTo investigate possible injection from pulse generator into the ground

Other observations:

As soon as pulse generator is connected to the shielding box, there is a potential difference around the box (ie. the potential is not homogeneous across the box).

The pulse generator seems to disturb the ground potential.

The pulse generator was set to have a 50ohm impedance.

A signal is observed at the ground pin once the pulse generator is connected.