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

Asynchronous registry and storage in 4-level fifo guarantees data loss < 4%when read-out through token ring

chargeinput

chargepreamp

FASTshaper 18.5 ns

peaking

SLOW shaper(2 stages)

140 ns peaking time

Peakdetector &

hold,free running

comparatorTime Walk

Compensationcircuit

PDHreset

pulse height

output

triggertimestamp reg.

dig. FIFO

analogue FIFO

Detection of Statistical, Poisson distributed signals

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

Experimental Built-in Safety-Belts with First Submission

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

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 fastshaper using the oscilloscope.

The one chip board with silicon strip detector with pitchof 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

Am140

noise

Test Pulse

noise

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