1. FEE for TPC MPD__NICA JINR
Yu.Zanevsky, A.Bazhazhin, S.Bazilev , S.Chernenko, G.Cheremukhina,
V.Chepurnov, O.Fateev, S. Razin, V.Slepnev, A. Shutov, V. Vereschagin, V.Zryuev
JINR, Dubna
S. Chernenko, NECC2011, September 13, 2011 1

2. MPD NICA
S. Chernenko, NECC2011, September 13, 2011 2

3. Time Projection Chamber (TPC)
TPC parameters
Size: 3.4 m (length) x 2.2 m (diameter)
Drift Length: 150cm
# of samples: 50
Electric field: 140V/cm
Magnetic field: 0.5 T (max.)
Gas: 90% Argon + 10% Methane (atm+2mbar)
Readout: 2x12 sectors (MWPC+pads or GEM)
Pad size – 4x10mm in inner sector area
6x12mm in outer sector area
Total # of pads: ~80000
Performance
Spatial resolution: srf~300 mm sz~ 2 mm
Two track resolution < 1 cm
Momentum resolution Dp/p < 3% (0.2<p<1 GeV/c)
dE/dx resolution < 8%
TPC prototyping has already started
S. Chernenko, NECC2011, September 13, 2011 3

4. MPD TPC prototyping (2) MPD TPC read-out specification
Field Cage
Rods
Diameter mm
Length mm
Wall thickness - 2 mm
Material – Kevlar
Readout – MWPC:
6x12 & 4x10 mm pads
Gas – Ar/CH4 (80/20)
MWPC readout
MPD TPC read-out specification
Readout: 2x12 sectors
Pad size: 5x12,5mm
Total # of pads: ~80.000
S. Chernenko, NECC2011, September 13, 2011 4 4 4

5. Front End Electronics Requirement
Total number of channels
MIP, noise < 1000e-
Dynamic Range………………… (10 bits)
Shaping time …………………….. ~200ns (smooth shape, S/N)
Sampling …………… MHz
Tail cancellation (after 1 s)…… < 1%
Temperature……………………… ~ 0.10 C (stable drift velocit)
Pcons …………………..……………..40mW/ch
S. Chernenko, NECC2011, September 13, 2011

6. Front End Electronics Component Base
FEE for TPC_MPD
two ASICs from ALICE TPC : PASA (analogue)
- ALTRO (digital)
REASONS
- availability (total needed number of channels )
- reliability
- good experience ● ALICE ~ chs
● STAR ~ chs (recent upgrade)
- no long R&D
S. Chernenko, NECC2011, September 13, 2011

7. STAR FEE Upgrade based on ALTRO+PASA (DAQ1000 )
> 10 times faster
DAQ 1000
Old TPC features
Zero suppression done at FEE in the Altro
Event transfer times smaller
Combined with slightly faster link, will allow rates ~ hz
Event Buffering on FEE
TPC stays alive as long as throughput is < max
Deadtime only caused by TPC Drift..
0.004% dead / hz readout
Zero suppression done at RB in the DAQ room
Full ~460, bit words transferred over each fiber.
10ms readout time every event. 100hz max rate.
No event buffering on FEE
TPC dead during digitization & readout time.
1% dead / hz readout.
S. Chernenko, NECC2011, September 13, 2011

8. Data flow (rate) Track Signals readout Induced charge on pads
Pad Plane Prototype
~ chs
Data flow (rate)
- event
(Z-suppresion  10% occupancy)
- 6kHz trigger  5 TPC
~ 2 Gb per chamber
- fast trtransmission + on-line data
reduction (upgrade STAR, ~100times) to
FEE
S. Chernenko, NECC2011, September 13, 2011

9. 64 chs FEE for TPC_MPD ALTRO ALTERA (control) TPC__MPD Readout
L1: 6 kHz
4 CHIPS x
16 CH / CHIP
4CHIPS x
16 CH / CHIP
drift region
40 ms
Front-end
Bus
ALTRO
Digital
Circuit
gating grid
PASA
Readout
controller
ADC
RAM
anode
wire
80.000PADS
pad
plane
CUSTOM IC
(CMOS 0.35mm)
CUSTOM IC (CMOS 0.25mm )
CSA
SEMI-GAUSS. SHAPER
1 MIP = 4.8 fC
S/N = 30 : 1
DYNAMIC = 30 MIP
BASELINE CORR.
TAIL CANCELL.
ZERO SUPPR.
10 BIT
< 10 MHz
MULTI-EVENT
MEMORY
GAIN = 12 mV / fC
FWHM = 190 ns
S. Chernenko, NECC2011, September 13, 2011 9

10. Processing in PASA & ALTRO
- FWHM – 190ns
- Baseline restoration after 1ms:
~ 5 % in amplifier / shaper
~ 0.1% in dig. chip
FWHM ~ 190ns
PASA
ALTRO
- Baseline corrections
- Tail cancellation
S. Chernenko, NECC2011, September 13, 2011 10

11. Conclusion - TPC is optimal tracking Detector for MPD
( high multiplicity environment, possibility for dE/dx measurement )
- TPC prototyping is in a good progress now
( development of field cage, pad plane, FEE and so on;
test with the laser )
- FEE is based on ALTRO and PASA chips (ALICE TPC)
ALTRO and PASA are available and can provide all required
parameters
- FEE prototyping is being planned to be completed in 2012
- TPC installation into MPD is being planned to be completed in 2016
S. Chernenko, NECC2011, September 13, 2011 11

12. Thank you for attention
S. Chernenko, NECC2011, September 13, 2011 12