Status of n-XYTER read-out chain at GSI

1. Status of n-XYTER read-out chain at GSI Rahul Arora r.arora@gsi.de GSI, Darmstadt GEM-TPC Meeting,18th November 2009

2. n-XYTER : Neutron- X, Y, Time, Energy Readout ASIC • Front-End: • 128 channels • Front end for either polarity input signals • Charge sensitive pre-amp and peak detector • Time stamping with 1 ns LSB, 2ns resolution • Peak detection and analogue storage (10 bit electronic resolution) • Purely data driven, autonomous hit detection (self triggered) • Average per channel hit rate 160kHz with 10% dead time • (determined by pile-up on slow channel) • Readout: • Per channel analogue energy and digital time stamp FIFO (1ns resolution) • De-randomizing, sparcifying Token Ring readout at 32 MHz

3. Data Driven Front-End: Asynchronous Channel Trigger Detection of Statistical, Poisson distributed signals triggertimestamp reg. comparator Time WalkCompensationcircuit FASTshaper 18.5 ns peaking PDH reset chargepreamp dig. FIFO chargeinput SLOW shaper(2 stages) 140 ns peaking time Peakdetector & hold, free running pulse height output analogue FIFO Asynchronous registry and storage in 4-level fifo guarantees data loss < 4% when read-out through token ring

4. n-XYTER Front End Topology

5. Power Consumption • preamplifier 7.4 mW • fast shaper 2.5 mW • slow shaper stage 1 1.7 mW • slow shaper stage 2 2.5 mW • discriminator 2.1 mW • peak detector and hold 2.7 mW • analogue FIFO 2.3 mW Overall we find about 21 mW/channel  air-cooling needed and installed for the tests

6. Testability and Diagnostics Individual analogue test channel Built in test pulse generator Programmable mask for every channel Programmable, forced trigger of PDH for every channel (check signal pedestal) Programmable dead time Diagnostic counters for pile-up and token statistics Backup Previsions / Safety Every individual channel may be shut off Clock signals derived on chip may be fed in separately Time stamp clock may be reduced without change of readout clock Various parts may be shut off In addition to global threshold, 5 bit programmable local threshold Experimental Built-in Safety-Belts with First Submission

7. N-XYTER FEB • Dimensions: 91 x 95 mm • 8 layers • Revision C

8. Readout chain • The readout chain starts with the Revision C board having 50 micron silicon strip detector on it having detector capacity around pF. • The source for the detector is Am140 • The next step is the ROC board connected to the FEB by flat cable. • The DC voltage supplied to the ROC and FEB is as follows • For ROC : Voltage - 5 V Current - 3 Amps • For FEB : Voltage - 5 V Current - 1.5 – 2.0 Amps • The versions of software and hardware used are • ROC hardware : 1.7.2.21 • ROC software : 1.7.2.0 • The ROC is communicated using ROCsoft software in a PC running linux. • The analysis is done using go4 sofware 4.3.1 • The FEB is maintained at a constant temperature of 20 °C using air cooler.

9. Testing of one chip board The pulse shapes are studied from the slow and fast shaper using the oscilloscope. The one chip board with silicon strip detector with pitch of 50 micron is tested using Am140 . The results are analyzed using go4 software.

10. Go4 plots for ADC count and channels ADC count for all channels

11. Event signal with baseline subtraction and test pulse signal noise noise Test Pulse Am140

12. Overall status & Known bugs • Operational tests: • Full chain is operational • Drift with temperature, but if stabilized works for days • Dedicated tests (with developer) • Cross talk (?) may be present (mixed layout?) • Temperature dependency of E-output (work below 60 °C)

13. Outlook • 2-chip board will be attacked as for as possible • Input to be changed to gas-detector • Data for the engineering run nearly complete • Submission foreseen before end of 2009