TAU - status

December 14

TAU - status report 2

Lab setup

9/7/2011

Each RO line is X100 Attenuated and 100Ω terminated

10 μm position precision of collimated source

Discriminator

10 RO lines

VME V560counter

HV line quenched with 20MΩ connected to a 1MΩ /100MΩ voltage divider

TAU - status report 3

Source position

9/7/2011

Source sits here

1cm thick, Delrin collimator, with a 3 mm slit opening

TAU - status report 4

All night measurement

• collimated Source was left on the same position (above RO channel 7) for ~14 hours.

9/7/2011

TAU - status report 59/7/2011

Each histogram shows the ratio between each channel and the channel beneath the source (7).

hour

ratio

1 2 3 4

5 6 7 8

9 10

TAU - status report 6

Position scan

• Each full turn of the micrometer moves the source by 1mm• Started the scan when the micrometer read is 60mm• Made 16 measurements each of 5minutes and 1mm apart. • CF4 gas, 600 Torr, 1316V .• Actual voltage on the panel is ~4/5 of the HV applied due

to the voltage divider.9/7/2011

TAU - status report 79/7/2011

49mm 50mm 51mm 52mm

53mm 54mm 55mm 56mm

60mm 59mm 58mm 57mm

cpm

Channel

TAU - status report 8

Source position measurement

9/7/2011

• points in this graph are the Gaussian fit results

• Errors are σ/√(n-1)• Numbers in the x-axis

have no global meaning, simply the read of the micrometer and not the distance from any real point in space…

• The electrode pitch in this panel (10 electrodes per inch) is the slope of this line: 0.4 electrodes per mm…

XY signal processing

• Measuring the pulse as a function of HV line number.

RO

85 24105 55

Volts

Time

Panel

HV

HV line Area Width at bottom

Width at 60%

Maximum

24 46.7 77 bins 21 bins 1.36

55 51.5 75 bins 33 bins 1.2

85 47.7 80 bins 64 bins 0.995

105 48.3 82 bins 57 bins 1.05

XY signal processing

• Cutting out the noise. Flipping the signal to the positive side. Trying to discriminate between the two pulses (table above).

• None of the quantities above seems to give good separation between the two pulses.

TAU - status report 11

Last minute plots …

• Seems that the r/o pulse can be parameterized according an electric damped oscillator

9/7/2011

cos( )tA e t

2

R

L

2

2

1

4

R

LC L

TAU - status report 12

r/o pulse fit

9/7/2011

If we supposed R=100 ohms, the

fit results gives C=15pF

Future plans

• Measuring the signal at stripe #1, we expect to get the signal shape with a factor 2. This should include the negative side of the bi-polar signal.

• Fitting the two pulses with the shape extracted from the above measurement. Allowing the location of the two signals to float.