1. The LNF test setup
Status as of

2. Geometry of LNF setup Top and bottom trigger counters
160 mm
4 KLOE-type tracking chambers
610 mm
One BESIII-(COMPASS-)type test chamber
200 mm
160 mm

3. 4 KLOE-type tracking chambers
One BESIII-(COMPASS-)type test chamber

4. The new BESIII-type test chamber, co-financed by INFN, IHEP and MAE

5. The cosmic trigger
The 2 trigger counters for cosmic rays are 12 by 15 cm2 scintillators (top PM HV: kV, bottom PM HV: -1 kV)
PM signals from top and bottom are sent to CAEN N417 discriminators with threshold 60 mV, stretched to 20 ns and coincidenced
The rate is 0.02 Hz, with a few % random triggers
The coincidence output triggers the SRS readout (APV25 electronics from CERN) and an Agilent DSO-X 3034A for monitoring

6. Trigger NIM logic
Trigger 27270

7. Trigger optimization
The 2 PM signals and the 2 discriminated ones are acquired via the scope USB port (triggered by the PMs AND) and analyzed separately
PM’s HV equalized looking at signal height
Fraction of random signals evaluated fitting the time difference between discriminated signals

8. Upper PM signal and timing
PM max signal from PM waveform scan
60 mV threshold
PM time slewing: smaller signals lead to a delayed coincidence
discr. time (ns) wrt coincidence

9. Lower PM signal and timing
PM max signal from PM waveform scan
60 mV threshold
PM time slewing: smaller signals lead to a delayed coincidence
discr. time (ns) wrt coincidence

10. Smaller PM signals have worse time correlation.
Below threshold are: 1) random with flat correlation
And 2) real coincidences with wider time distribution

11. Fitting the fraction of casuals
Events with high signal and good timing
Events with smaller signal and less good timing
Flat casual distribution, 0.2% in total range
BUT: unknown fraction of cosmic showers, ineliminable…

12. The gas system (Hdwr)
The 2 gases (Ar and iC4H10, isobutane) are in bottles in the gas house, 100 m away from the setup
Two separate gas lines transport the gas to MKS mass flowmeters, read out by a 647C digital controller
Mass flowmeter ranges are 500 (Ar) and 50 (iC4H10) cm3/min, nominal resolutions: 0.1% of range
The gas mixture used is (90±0.5) cm3/min (Ar) and (10±0.05) cm3/min (iC4H10)

13. Ar (Ch.1) and iC4H10 (Ch.3) mass flowmeters
The gas mixing cylinder

14. The MKS 647C readout controller

15. Gas/HV software interlock
Readings from the 647C serial ports reach a Moxa NPORT 5450 serial server, that emulates via Ethernet 4 serial ports to the slow-control PC
The slow-control PC is a VirtualBox Windows XP, running on the same Scientific Linux 6 DAQ PC
In the XP subsystem, 2 LabView VIs (one DataSocket publisher and one subscriber) monitor and log to disk gas flow readings
One additional subscriber VI implements a software interlock for the HV-controlling VI

16. The Moxa NPORT 5450 Serial Server, with its Serial Port inputs and Ethernet connection

17. The Windows XP VirtualBox: the monitor VI is a DataSocket publisher of date-stamped gas flow readings. The slow logger VI is a DataSocket subscriber that writes gas flows to disk. The Watchdog VI analyzes flow and current readings and publishes the Alarm flag, to which the HV slow control subscribes.

18. HV hardware Based on a CAEN SY1527LC crate, with 3 A1550P boards
28 channels for the 4 tracking chambers from KLOE
14 channels for one (later two) test BESIII chamber(s)
For redundancy and crosscheck the HV state is echoed (and possibly killed in an emergency) using a local monitor and keyboard
Channel currents (below CAEN system capabilities) are read by a 24-channel nanoAmperometer with 1 nA resolution (design by LNF-SELF service)

19. The CAEN controller with its Ethernet connection, and AUX video and keyboard cables. The SELF nanoAmperometer, with its CANBUS interface

20. The 7 “physical” HV channels of a GEM
For each chamber we use 7 HV channels:
Cathode HV
3/5 mm drift gap
GEM 1 “Up” HV
GEM 1 “Dn” HV
2 mm gap
GEM 2 “Up” HV
GEM 2 “Dn” HV
2 mm gap
GEM 3 “Up” HV
GEM 3 “Dn” HV
1 mm gap
Anode (readout), GND

21. The 7 logical HV channels of a GEM
The 3 “GEM” potentials determine gain:
Gain 1 is (exp) function of (HVG1up-HVG1dn)
Similarly for gains 2 and 3
Overall gain = Gain1*Gain2*Gain3
The 4 “transfer” HV’s only move electrons to the next stage:
(HVcathode-HVG1up) moves electrons away from cathode towards GEM1: this is called the “drift” field
Same for middle gaps
(HVG3dn-GND) moves electrons away from GEM3 to the readout layer: this is called “induction” field

22. The LabView VI for monitor and control of GEM channels
The LabView VI for monitor and control of GEM channels. Communications with the SY1527LC crate are handled by an HV OPCServer low-level driver written by CAEN. This VI implements a gas/HV safety software interlock.

23. HV for tracking chambers
“physical”
Top/Mid/Bot (kV)
V cathode
-2.76/-2.75/-2.74
V G1 Up
-2.46/-2.45/-2.44
V G1 Dn
-2.17/-2.15/-2.14
V G2 Up
-1.87/-1.85/-1.84
V G2 Dn
-1.58/-1.57/-1.56
V G3 Up
-1.28/-1.27/-1.26
V G3 Dn
-1./-1./-1.
“logical”
Top/Mid/Bot
Drift
1./1./1. kV/cm
Transfer 2
1.5/1.5/1.5 kV/cm
Transfer 3
Induction
5/5/5 kV/cm
Gain 1
295/295/295 V
Gain 2
290/285/285 V
Gain 3
280/270/260 V
These tables are kept for reference, they were used for the old KLOE2 gas mixture

24. HV for tracking chambers
“physical”
Top/Mid/Bot (kV)
V cathode
-3.49
V G1 Up
-3.04
V G1 Dn
-2.76
V G2 Up
-2.16
V G2 Dn
-1.88
V G3 Up
-1.28
V G3 Dn
-1.
“logical”
Top/Mid/Bot
Drift
1.5 kV/cm
Transfer 2
3 kV/cm
Transfer 3
Induction
5 kV/cm
Gain 1
280 V
Gain 2
Gain 3
Gas mixture: Ar-iC4H10 90%-10%

25. The nanoAmperometer interface
The LNF-SELF 24-channels nanoAmperometer, with a CAN-bus interface, is read via a Kvaser USBCanII by a LabView set of VIs
For now, we monitor 15 channels
All 7 channels of the new BESIII test chamber
The 2 most critical channels of each tracking chamber: G3Up and G3Dn

26. The LNF-SELF nA-meter Partially funded by PGR00136
Italy-China MAECI program

27. In the plot on the left, current time-histories for 6 “tracking” channels: the peaks appear normally in the chamber ramp-up phase. In the plot on the right, the same for all 7 channels of the new BESIII test chamber

28. The tracking chambers
The 4 tracking chambers are KLOE2-type, designed and made by a LNF-Bari collaboration
Each chamber has X-Y orthogonal views, read by 2 APV25 chips, a CERN-RD51 project
The active area is 128 strip wide in X and Y
With 650 mm strip pitch, the active area is 8.3·8.3 cm2 wide

29. X- and Y-strip planes, each plane has 128 strips and is read out by 2 APV25 chips, yielding 128 charge values, for 27 time samples (25 ns apart)

30. The DAQ system
The APV25 chips are connected to an SRS board via HDMI cables, design by CERN-RD51
The SRS board, in a custom crates, is read out by the DAQ PC via a common Ethernet port

31. The SRS crate, connected via Ethernet to the DAQ PC, running Scientific Linux 6
(DAQ and board-configuring software by CERN)

32. DAQ numerology and def’s
Y view, chip 7
X view, chip 5
Y view, chip 6
X view, chip 4 z y
Y view, chip 10 x
X view, chip 8
Y view, chip3
X view, chip 1
Y view, chip 2
X view, chip 0

33. Results from cosmic setup
Request 2 hits in both top and bottom tracking chambers to define a cosmic track
Plot in the other 3 chambers the residual “expected-measured”
Alignment in X and Y (test chambers only)
Fit the residuals with one gaussian
Cosmic rays technique not ideal 
No momentum cut
Cosmic showers (?)
Geometric mismatch PMs/ chambers …

34. Choose the right SRS timebin

35. X residuals
External chambers errors unsubtracted

36. Y residuals
External chambers errors unsubtracted

37. Fixing rotations takes lots of stat….

38. Fixing rotations takes lots of stat….