1 Domenico Di Filippo

CHANTI Update and High rate effects

Fabio Ambrosino,Tiziana Capussela,

Michele Corvino (B.Sc.),Domenico Di Filippo,

Paolo Massarotti,Marco Mirra,

Marco Napolitano,Giulio Saracino

2 Domenico Di Filippo

100% of bars to produce 6 additional stations completed We need ~1 month to finish bar characterization Station assembling will start in ~ 1 month. It will take ~1 week

per station. small vessel 90% completed in Napoli Mechanical Workshop.

Assembly & welding of the full two vessels system two expected to start in < 1 month.

The tender for the building of CHANTI front-end electronic is closed. The production has started, delivery expected mid March.

CHANTI Status

3 Domenico Di Filippo

DCS

A draft version of DCS specification for the CHANTI is ready and will be in EDMS by end of the week.

Starting the next week I will be at CERN working on the DCS software.

4 Domenico Di Filippo

We expect a mean rate of about 500 kHz on a single CHANTI bar (see Marco Mirra talk at software meeting).

In order to get an estimation of the high rate behavior of the CHANTI electronic we use BTF data taken last summer (analysis performed in Michele Corvino B.Sc. Thesis work)

High rate efficiency estimation

Flash ADC

Beam: 575 MeV e-Rate: O(Hz)Multiplicity: O(1)

Tag1 Tag25 Bar CHANTI prototype. 2 channel instrumented.

e- beam

5 Domenico Di Filippo

Emulating high rate with BTF data

Peak delay (us)

Event #

Some events present two distinct peaks (they are not particle of same burst because there are about 20 ns between them). Restricting our analysis to these kind of event we can emulate high rates

6 Domenico Di Filippo

Efficiency on the 2nd peak

Peak Delay (us)

0.924

Dead time < 60 ns. We (conservatively) estimate an inefficiency of about 2%.

1st peak revelation efficiency; it is due to acceptance.

7 Domenico Di Filippo

Tot board calibration setup

PC (Linux)

VME Bus

HP

TD

C

ArbitraryWaveformGeneratorS

igna

l spl

itter

(trigger)CAEN bus over USB

Tot Board(LVDS over HD cable)

( Thanks to Frascati and F.Gonnella for the TDC controlling software )

8 Domenico Di Filippo

Tot board calibration strategy

Trail threshold

Lead threshold

(base-Tot)*slope = Th_trail

(base-Tot)*slope = Th_lead

We first add a stable part to the signal to not stress the electronic

100 ns 100 ns147 mV

9 Domenico Di Filippo

Threshold calibration

Threshold (DAC count)

Thr

esho

ld (

mV

)Trail ThresholdLead Threshold

10 Domenico Di Filippo

Hysteresis

Threshold (DAC count)

Hys

tere

sis

Reproducibility

11 Domenico Di Filippo

Signal width dependanceThe CHANTI signal have not the flat region, so we want to check the ToT behavior in more realistic condition

There is an unexpected width behavior.

width 100 ns

Trail ThresholdLead Threshold

Thr

esho

ld (

mV

)

Width (ns)

12 Domenico Di Filippo

DC cut

Looking at the Tot 4-channel analog adder, it seem to be there a sensible DC cut.

Big (in charge) signals get a (positive) offset, so we get a wrong threshold estimation.

This could be a problem in high rate environment because the signal mean charge could sensibly differs from zero.

13 Domenico Di Filippo

DC cut effect on CHANTI

We expect a ~500kHz rate i.e. 2000 ns period.

However we use a signal with 3x the real signal charge, so it is comparable with 6000 ns with real signals.

So, this effect should be under control. More (direct) test soon...

CHANTI working point at ~6000

100 ns50 ns

Trail ThresholdLead Threshold

Period (ns)

Thr

esho

ld (

mV

)