1. 1Domenico 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. 2Domenico 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. 3Domenico 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. 4Domenico 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) Tag1Tag2 5 Bar CHANTI prototype. 2 channel instrumented. e- beam

5. 5Domenico 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. 6Domenico 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. 7Domenico Di Filippo Tot board calibration setup PC (Linux) VME Bus HPTDC Arbitrary Waveform Generator Signal splitter (trigger) CAEN bus over USB Tot Board (LVDS over HD cable) ( Thanks to Frascati and F.Gonnella for the TDC controlling software )

8. 8Domenico 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 147 mV

9. 9Domenico Di Filippo Threshold calibration Threshold (DAC count) Threshold (mV) Trail Threshold Lead Threshold

10. 10Domenico Di Filippo Hysteresis Threshold (DAC count) Hysteresis Reproducibility

11. 11Domenico Di Filippo Signal width dependance The 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 Threshold Lead Threshold Threshold (mV) Width (ns)

12. 12Domenico 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. 13Domenico 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 Threshold Lead Threshold Period (ns) Threshold (mV)