AFTER TPC readout electronics P Baron 1 A

AFTER- TPC readout electronics P. Baron 1, A. Delbart 1, X. de la Broise 1, D. Calvet 1, E. Delagnes 1, F. Druillole 1, J-L. Fallou 1, E. Mazzucato 2, F. Pierre 2, A. Sarrat 2, , E. Virique 1, E. Zonca 1, M. Zito 2. 1 CEA Saclay, DSM/DAPNIA/SEDI, 91191 Gif-sur-Yvette Cedex , France 2 CEA Saclay, DSM/DAPNIA/SPP, 91191 Gif-sur-Yvette Cedex , France Lolly. Pollacco Modified the file Of Pascal Baron pascal. baron@cea. fr The T 2 K experiment The TPC Electronic architecture The AFTER ASIC Results Status Conclusions Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 1

The T 2 K experiment • Goal: Study of neutrino oscillation • J-PARC: 50 Ge. V synchrotron (under construction) • ND 280 m: Near detector at 280 m from the neutrino production target J-PARC, Tokai Super Kamiokande ND 280 Kamioka Time schedule: Q 3 2009 Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 2

The T 2 K TPCs 359 mm 2. 5 m 342 mm 2. 5 m 1 m 1726 active pads Bulk Micromegas 12 detector modules per TPC plane => 72 modules => 124. 272 pads !! Design of a novel compact readout electronics Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 3

Initial Requirements & Constraints • Store and digitize the detector signal over a 511 sample time window larger than the drift time over 12 bits. • Must be versatile to be usable with various end-plate detectors and gas (not defined at the beginning of the design Q 1 2005): • compatible with both polarities of signal, programmable gain • Sampling frequency adjustable (1 MHz-50 MHz) • Short time development (2 years for the all electronics) => architecture with limited risks and use of mature technologies. • Minimum power consumption (detector inside magnet). • Minimize the cabling between detectors and acquisition. • Low cost • But, fortunately: • Low Event rate: beam rate ~0. 3 Hz; cosmic ~ 20 Hz. • External trigger available. Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 4

Read-out Electronic Architecture A Highly multiplexed architecture to reduce the power consumption taking benefit of the low event rate 432 FEC ~124. 000 channels 1 -6 Tbaud*/s peak Pre-amp and shapers 1728 AFTERs 432 ADCs Samplers and multiplexers Analog to digital conversion 72 Mezzanine cards ~2 ms retention max. 34 Gbaud/s peak On-detector electronics 400 Gbit/s peak Digital buffer 72 Optical fibers 6 Concentrator Cards Standard LAN connection(s) *1 baud = 10 bit ~1 -10 Gbit/s averaged Data concentration ~0. 1 -1 Gbit/s Shared DAQ system Architecture principles • AFTER ASIC : 72 channels; Signal amplified & stored in the SCA (511 cells) • External trigger: digitization of the totality of the SCA of all the channels (2 ms) • ADC + digital buffer mounted close to the detector • Multiple optical fibers send data to off-detector concentrators • Interface to common DAQ via standard network Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 5

Detector A Read-out Electronic Architecture Réseau DAQ control 3 TPC Outside magnet Gigabit Ethernet TCP/IP 12 duplex Inside magnet 1 m 5 Optical fibres Global trigger VME/PCI backplane bus 6 DCCs 2, 5 m 2, m Detector B 1 of 6 TPC planes (12 -modules) x 6 1 of 6 Data Concentrator Card PC Linux 1 of 72 modules 1728 pad Micromegas plane 288 channel Front End Card (FEC) 1 of 1728 Front-End ASIC “AFTER” Slow control network Front End Mezzanine Card (FEM) Optical fiber to/from DCC Low voltage Power supply Micro Pattern Gas Detectors. Towards an R&D Collaboration 72 channel x 511 time buckets Switched capacitor array CERN, 10 September 2007 6

Assume that … • • 50 cm diameter 0. 25 cm²/pad 8000 pads 10, 000 pads AFTER 72 Channels/ASIC 160 AFTER chips 36 FEC 6 FEM 1 Optic Concentrator 50 cm 1728 pad Micromegas plane 288 channel Front End Card (FEC) Card (FEM) Optical fiber to/from DCC Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 7

Then … • An event of two traces will give us – 300 fired pads – 300 x 511 x 2 bytes = 306 Kbytes = • Assume 1, 000 events/sec – 306 Mbyte/sec – Need 1 GHz through-put • Am not sure we can afford the 1 k events/sec • Rise –Time difficulty • Placing the AFTER layout – Dead-time is common for the full AFTER chip Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 8

AFTER 76 to BUFFER 1 PA TEST In Test • • • SCA FILTER SLOW CONTROL ADC 511 cells Power On Reset Serial Interface Main features: Input Polarity: positive or negative 72 Analog Channels 4 Gains: 120 f. C, 240 f. C, 360 f. C & 600 f. C 16 Peaking Time values: (100 ns to 2µs) 511 analog memory cells / Channel: Fwrite: 1 MHz- 50 MHz; Fread: 20 MHz SCA MANAGER Asic Spy Mode W / R CK Mode CK CSA; CR; SCAin (N° 1) • • • Slow Control No zero suppress. No auto triggering. Power on reset No selective readout. Test mode: calibration or test [channel/channel] functional [72 channels in one step] • Spy mode on channel 1: CSA, CR or filter out AFTER Main Features Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 9

AFTER BUFFER PA TEST In Test • • • ADC SCA FILTER SLOW CONTROL ADC 511 cells Power On Reset Serial Interface SCA MANAGER Asic Spy Mode W / R CK Mode CK Main features: Input Polarity: positive or negative 72 Analog Channels 4 Gains: 120 f. C, 240 f. C, 360 f. C & 600 f. C 16 Peaking Time values: (50/100 ns to 2µs) 511 analog memory cells / Channel: Fwrite: 1 MHz-100 MHz; Fread: 20 MHz CSA; CR; SCAin (N° 1) • • • Slow Control No zero suppress. No auto triggering. Power on reset No selective readout. Test mode: calibration or test [channel/channel] functional [72 channels in one step] • Spy mode on channel 1: CSA, CR or filter out AFTER Main Features Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 10

Possible Changes • • Pre-amp also outside Slow controlled Shaper Disc Trigger (Sum of Disc) – Slow controlled Selective read-out via FPGA Selective trigger via FPGA Increase in gain by x 2 possible Increase of an ADC at 20 MHz read-out Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 11

Layout & package • • • Technology: AMS CMOS 0. 35µm Area: 7. 8 x 7. 4 mm 2 Package: LQFP 160 (28 x 1. 4 mm) Run: April 2006 Delivery: August 2006 Test: Start in October 2006 SCA : 76 x 511 Cells Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 12

AFTER Test set-up Evaluation kit (Memec) Xilinx Virtex 2 pro Interface card LABVIEW Test Software Font-end ASIC Test Card Protection 1: diodes + Photo. MOS Protection 2: diodes ASIC Test Socket Protection 1 Micro Pattern Gas Detectors. Towards an R&D Collaboration Protection 2 No Protection CERN, 10 September 2007 13

Pulse Shape FWHM Range Tpeak (5% -100%) Tpeak (100% -5%) FWHM 100 ns 200 ns 400 ns 1µs 2µs 111 ns 185 ns 387 ns 893 ns 1776 ns 182 ns 552 ns 823 ns 2118 ns 4037 ns 150 ns 287 ns 631 ns 1529 ns 2953 ns Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 14

Charge Gain Charge Range 120 f. C 240 f. C 360 f. C 600 f. C Gain 18 m. V/f. C 9. 7 m. V/f. C 6. 7 m. V/f. C 4. 1 m. V/f. C Spread (ASIC) 5. 6% 4% 3. 8% 3. 4% Spread (50 ASICs) 12% 8% 7% 6. 5% Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 15

Linearity Measured INL < 1. 2% Full range Specification: 1% [0 -3 MIPS]; 5% [3 -10 MIPS] At 100 MHz, the INL is the same Range: 120 f. C; FCKW=50 MHz Large speed margin of the system !! Peaking Time: 100 ns Range: 120 f. C; FCKW=100 MHz Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 16

Pedestals Baseline of 1 Asic x 76 channels Spread: 160 to 300 ADC bin peak-peak Baseline of 50 Asics x 76 channels Spread: 360 ADC bin peak-peak The mean value is controlled on the FEC card. It will be fixed to the same value on all the TPC FEC cards Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 17

Equivalent Noise Charge on ASIC Noise equation for AFTER The current of CSA input transistor is controlled on the FEC Icsa : 400µA Icsa : 800µA measured (dots) and parameterized (lines) for the 120 f. C range Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 18

Input Protection Circuit Need to protect the electronic against spark • Input Protection diode in ASIC, but robustness ? ? => Input Protection diode on the FEC The TPC must work without distortion of the electric field even in case of problem on a Micomegas module • No access to the module inside the magnet during data taking Þ Photo. Mos to disconnect the pad from the ground [1 Photo. Mos for 2*72 channels] 1 V 220 p. F In ASIC PAD 100 MΩ s ad p er Photo. MOS h Ot Pad capacitance Measurements on module MM 1_005 7 to 17 p. F Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 19

Equivalent Noise Charge on TPC module Range: 120 f. C Target value: ENC <750 e - T 2 K: 200 ns or 400 ns Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 20

Equivalent Noise Charge on TPC module Range: 240 f. C Target value: ENC <1500 e - Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 21

Equivalent Noise Charge on TPC module Range: 360 f. C Target value: ENC <2250 e - Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 22

Equivalent Noise Charge on TPC module Range: 600 f. C Target value: ENC <3750 e - Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 23

ASIC Cross-talk Ch 16 Ch 17 Ch 19 Cross-talk is proportional to the distance / ch 18 Pedestal & FPN subtracted < +/- 0. 4% The crosstalk is mainly derivative Relative Cross-talk amplitude (Amplitudes normalized by the 18) Average output Ch 18 • Asic connected to the MM 03; Calibration mode • High signal on ch 18; Range: 120 f. C; TPeak =100 ns Ch 20 18 Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 24

SCA leakage Current Reading Phase: 2 ms 1 (asic) x 76 (channels) x 511 (memory cells) High leakage current can degrade the signal/noise ratio < 1 ADC bin 97% < 0. 5 ADC bin Amplitude variation for 2 ms of memory time Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 25

Power & Yield The main current sources are controlled on the FEC card • Icsa = 400µA; 1. 88 m. A & 6. 25 m. W per channel (135. 5 m. A & 447 m. W per ASIC) • Icsa = 800µA; 2. 28 m. A & 7. 52 m. W per channel (164. 2 m. A & 542 m. W per ASIC) Yield on a total number of 198 Asics: 73% Example of bad chip Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 26

Status of electronic Present Status AFTER • 200 ASICs tested • Foresee PRR in 12 October 2007; production in ~Q 4 -2007 Present Status FEC • 7 boards produced and tested • Foresee PRR in ~Q 1 -2008; production in ~Q 2 -Q 3 2008 Present Status FEM • 1 board produced and tested • Foresee PRR in ~Q 2 -2008 & Production in ~Q 3 -Q 4 2008 Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 27

Present Status of TPC module Micromegas Module + 1 FEC tested at Lab with 55 Fe source Ar(95%)/i. C 4 H 10(2%)/CF 4(3%) ~8% energy resolution @ 5. 9 ke. V Emesh = 350 V Edrift = 200 V/cm Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 28

Present Status of TPC module 1 complete Module will be tested at the end of September in the HARP cage for cosmic tests HARP flange 1 Micromegas Detector 1 FEM Trigger NIM->LVTTL 20 -30 m Optical fibre 1 reduced DCC 6 FECs Linux PC RS 232 (Console) Ethernet #2 (DAQ) Ethernet #1 Power Supply (PC ATX) Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN LAN CERN, 10 September 2007 29

Conclusion üCompact readout electronic for large TPC ü The Tests prove the full functionality of the electronic ü The next week, the complete TPC module will be tested with cosmics üAFTER upgrade for nuclear projects: selective readout; threshold/channel & auto triggering Micro Pattern Gas Detectors. Towards an R&D Collaboration CERN, 10 September 2007 30