Trigger system for the T600 detector: applications to Supernova detection G. Fiorillo for the ICARUS...

Trigger system for the T600 detector: applications to

Supernova detection

G. Fiorillofor the ICARUS Collaboration

CRYODET WorkshopLNGS, March 13-14, 2006

G. Fiorillo Cryodet Workshop, LNGS 13 March 2006 2

View of the inner detector

T600 semimoduleCryostat (half-module)

Readout electronics


ICARUS DAQ


Physics considerations

• Events in T600 at LNGS:– Cosmic rays muons– Atmospheric neutrinos– Solar neutrinos + neutrons E ~ 5 MeV– Neutrinos from Supernova (burst) E ~ 20 MeV– Proton decay– CNGS neutrinos external timing– Beam muons


Event topologies

Cosmic-ray shower Muon

Low energy electrons


Data volume (A. Rubbia ICARUS IM Sept.02)

event/year wires/event drift factor of average total size number DLTin T600 samplescompression size per year equivalent(order of 4 in in GB (40GB/DLT)magnitude) Mbytes

solar neutrino 3000 27648 2500 4 32,96 97 2,4neutron capture 6000000 27648 2500 4 32,96 193119 4828,0muon crossing 2,00E+06 27648 2500 4 32,96 64373 1609,3side rock event 1,00E+05 27648 2500 4 32,96 3219 80,5atmospheric-like event 1,00E+03 27648 2500 4 32,96 32 0,8supernova event 0 27648 2500 4 32,96 0 0,0proton decay 0 27648 2500 0,0

TOTAL w/o low energy 67720 1693,0TOTAL with low energy 260743 6518,6

– 1.5 m drift or 1 ms is 2500 samples of 400 ns

– 27130 wires with 2500 drift samples

– 32 wires per board x 18 boards per crate x 48 crates= 27648 readout channels of 2500 samples

Total volume: 260 TB per year (25% CMS or ATLAS experiment!)

Volumes are dominated by physics backgrounds: neutron capture and muon crossing


Neutrinos from Supernovae

€

ν e + 40Ar→40Cl* + e+

• Elastic scattering from neutrinos (ES)

• Electron-neutrino absorption (CC)

• Elastic scattering from antineutrinos (ES)

• Electron-antineutrino absorption (CC)

(νe)+0.15 (ν + ν)

νx +e− → νx +e−

νe+40Ar→ 40K * +e−

(νe) Q=5.885 MeV

€

ν x + e− → ν x + e−

(νe)+0.34 (ν + ν)

(νe)Q≈8 MeV

low energy reactions in Argon


Shock breakout

collapse

OscillationNo

oscillation

757

730

27

Non adiabatic

1036

995

41

Adiabatic

Expected events from SN at 10 kpc in 3 kton

244TOTAL

203absorption

41Elastic

reaction

A.Rubbia, I.Gil-Botella


Supernova burst• Specific time structure

– Ex.: ~ 100 SN triggers in T300 in 1 sec(expected for a SN at 10 kpc, with an energy release of 1053 erg)

• Global trigger (full detector readout): bandwidth + storage problem– 1 event = 27648 ch 2500 samples 2 bytes

~ 130 MB 13 GB total

– DAQ throughput limit: < 40 MBytes/s (or >5 minutes to empty buffers)

• Local trigger: SN events are localized and limited to 1 crate per view– 5 events per crate (on average) in COLL + IND2 views ~ 40

MB/crate– 13 events per crate (on average) in IND1 view ~ 60 MB/crate

Each crate can be read-out as a separate event


Segmented trigger• Intrinsic granularity of the trigger is

a crate

• The requirement of the Supernova trigger introduces two types of triggers

– Global triggers: an entire T300 is readout as a single event

– Local triggers: the various crates are readout independently as separate events Overlapping in time local triggers

can be reconstructed offline (or online) using the absolute time information

• The implementation of local triggers presupposes the development of a small “local trigger control unit” card in each crate


Segmented trigger pixel definition

Rack 1Rack 20

Rack 11Rack 13

T600 Half Module – 1 chamber viewed from cathode

1 pixel area: ~ 0.6 m2

Total Number of Pixels ~ 80

32 x 9 Induction II

wires

32 x 9 Collection

wires

864 mm


MC simulation: low energy eventsICAFLUKA


MC simulation: high energy eventsICAFLUKA


Preliminary considerations• Trigger rate is dominated by physics background

– Neutron capture rates expected in T600 (ICARUS/TM-

2002/13): • 210-4 s-1 from natural radioactivity of the rock• 0.030.1 s-1 from Al container

• Segmented trigger potentially solves bandwidth and storage problems

• Event pre-classification data streams– extraction of solar neutrino data from low energy

stream

• Test bed for larger LAr detector low energy trigger


Trigger Input

• PMTs (global and local triggers)

• DAEDALUS (Based on single wire information)

• AWS (Analog 32 wires sum, exists on the front-panel of each analogue card, local triggers)

• External (beam profile chambers, cern-spill, …global)

G. Fiorillo Cryodet Workshop, LNGS 13 March 2006 16[x 50 ns]

PMT signal

The high light yield measured in T600 provides the natural solution for T0 definition and (in part) for trigger

PMT system


A PMT based trigger

• The PMT system allows for the design of a fast triggering system able to select the events on the basis of the scintillation light produced in liquid argon.

• The study is based on the MC simulation of real events inside the T600 detector.

• The contribution due to the dark counts and noise is taken into account.

• The segmentation of the sensitive volume according to the PMT layout permits the definition of local triggers.


Trigger Efficiency PlotsThe plot summarizes the trigger efficiency (triples case) as a function of the

electron kinetic energy, for different threshold values (G.Raselli IM Jan06).


Trigger Efficiency Tables

10

7

0.5 1.5

5

2

15

3

31Threshold

(phe)Energy(MeV)

98.3%

6.2 Hz

Trigger efficiency / Stochastic rate

(triples case)

99.7%

99.9%

99.9%

99.9%

95.2%

99.1%

99.8%

99.9%

99.9%

86.1%

97.9%99.1%

99.8%

99.9%

73.6%

93.3%97.1%

99.4%

99.9%

46.2%

80.2%

92.8%

97.9%

99.6%

6.2 Hz

6.2 Hz

6.2 Hz

6.2 Hz

1.1 Hz

1.1 Hz

1.1 Hz

1.1 Hz

1.1 Hz

0.2 Hz

0.2 Hz

0.2 Hz

0.2 Hz

0.2 Hz

<0.1 Hz

<0.1 Hz

<0.1 Hz

<0.1 Hz

<0.1 Hz

«0.1 Hz

«0.1 Hz

«0.1 Hz

«0.1 Hz

«0.1 Hz


Basic design requirements

• Redundancy important to measure efficiency• Global trigger:

– Generated by PMTs or external– drift deadtime GLOBAL_DRIFT (1ms)– Read-out deadtime GLOBAL_BUSY (1s) vetoes new

global triggers– Local triggers vetoed during GLOBAL_DRIFT

• Local trigger:– Generated by AWS + PMT– LOCAL_DRIFT (1ms) vetoes new local triggers


Trigger System Architecture

LTCU: discriminates the inputs, has one independent

threshold for each input, gives 1st level trigger

proposals as output; TCU:

performs coincidences between LTCUs proposals,

processes the fired pixels to study and label the event topology, produces global or local trigger proposals;

Trigger Supervisor: monitoring of the trigger and

the DAQ system, statistical functions.


Trigger System Architecture

LTCU TCUTRIGGER

SUPERVISORDAQ

CERN or any other external request

20 boards per chamber

(80 boards for T600)

from v791

n-bit request

v816

96

9

4 boards per T600

9

Trigger

Distribution

T120

T220

T11

T21

PMT LTCU


• LTCU discriminates the 18 inputs comparing them with remotely controlled thresholds. Noisy inputs can be masked

• Gives as output two separate trigger proposals (T1 and T2), corresponding to the OR of INDII or COLL boards respectively

• Test mode to check the working status

• Counting capabilities to check rates of trigger proposals for each input

• Board functionalities are driven by a remote controller

TCULTCU

9 T1

T29

from v791

• 1 board per crate - 20 boards per chamber

• each board receives as input 9 + 9 coming from the v791 analog boards (generally 9 of 2nd induction and 9 of collection)

1st trigger level: LTCU


• 1 board per chamber

• VME standard

• each board receives as input 40 signals from the AWS LTCUs (2 T signals x 20 boards) and N signals from PMT LTCU

• TCU performs coincidences between:

• the wire planes (in a ~3 s time window),

• the PMT signals,

• the external requests

• checks Majority, Minority, 2D Pattern logic conditions

• event is labelled according to topology

• An n-bit-word trigger request is sent to the Trigger Supervisor, defining the fired crates

2nd trigger level: TCU

CERN or any other external request

TS

T11

LTCU

TCUT1

20

T220

T21

n-bit request

PMT LTCU

AWS


TRIGGER SUPERVISOR

DAQ

n-bit request

v816

96

Trigger Distribution

• 1 or more boards

• VME standard

• TS receives 4 input n-bit-words from the TCU and the ABS CLOCK

• TS evaluates if the trigger request from TCU corresponds to a Local Trigger or a Global Trigger

TCU

• Monitoring of the system and validation of Trigger requests.

• GLOBAL/LOCAL DRIFT/BUSY Logic

• Trigger signal distribution to the v816

• Event trigger tag (trigger number, time, type, acquisition dead time…)

• Statistics for the trigger system

ABS CLOCK

Trigger Supervisor


TS GLOBAL/LOCAL Logic

• Trigger classification depends on:

• Energy deposition/number of PMT fired.

• Detector occupancy

• 2D/3D Pattern of fired pixels

• TS gives GLOBAL trigger when a MAJORITY condition is met in PMT logic

• Otherwise the trigger is LOCAL


The trigger generation algorithm


Time DiagramPMT

Induction II signal

Collection signal

LTCU T1 signal

LTCU T2 signal

TCU Trigger request

TS Trigger signal

T 3 s

T 1.5 ms Trigger dead time

n-bit


FPGAInput stage

RS232 interface

10 MHz oscillatorPower supply

18 inputsTrigger outputs

DAC

The LTCU prototype v1.0

IN

VDAC

Discriminator

Voltage follower

RC filterOUT

IN


VME INTERFACE Xilinx Spartan XC2S100 INPUT STAGE Xilinx Spartan XC2S100 SYNCHRONOUS FIFO IDT72V263

80 programmable input / output

2nd level Prototype TCU


Summary

• The readout of SN events, due to their burst nature, requires the implementation of local triggers to overcome data volume problems

• The segmentation of the sensitive volume permits the definition of local triggers potentially solving bandwidth and storage problems

• Event pre-classification by the trigger allows for the definition of data streams (useful for the analysis)

• Redundancy in the trigger system is important in order to measure the efficiencies

Segmented Trigger architecture based on PMTs and Wires Global trigger: the full detector is read-out as a single event Local trigger: only active “pixels” are read-out as separate events Events are labelled according to pixel topology


LTCU prototype for AWSv1.0


LTCU v1.0


The LTCU functionalities v1.8i

• Mask the input channels; • Read the mask status;• Set the thresholds;• Monitor the trigger rate

for each input;• Discriminator test mode;• Select one discriminator

output put on front panel.

All the board functionalities are remotely controlled via RS232 interface.


V1.0 test on 50 liters LAr TPC


Trigger rate test chain

• LTCU inputs = 4 signals from collection plane;

• Trigger generated from only one input (no FastOR);

• LTCU trigger output distributed to V816 module.

LTCU Trigger OUT

V789

LTCU

V791Ind Coll

IN IN IN IN IN IN IN IN

OUT OUT OUTOUT OUTOUT OUT OUT

IN

OUT

IN

Analog OUT

V816

trigger

PC (RS232)


Trigger Rate Plateau (I)Trigger rate for v791 n°1 in LTCU ch0

0

5

10

15

20

25

0 20 40 60 80 100 120 140

Threshold (mV)

Trigger rate (Hz)

Trigger rate for v791 n°2 in LTCU ch1

0

5

10

15

20

25

0 20 40 60 80 100 120 140

Threshold (mV)

Trigger rate (Hz)

Plateau zones


Trigger rate for v791 n°4 in ch5

0

5

10

15

20

25

30

0 20 40 60 80 100 120 140

Threshold (mV)

Trigger rate (Hz)

Trigger rate v791 n°3 in LTCU ch4

0

5

10

15

20

0 20 40 60 80 100 120 140

Threshold (mV)

Trigger rate (Hz)

Trigger Rate Plateau (II)

Plateau zones


Trigger efficiency test chain

• LTCU inputs = 4 signals from collection plane;

• One LTCU IN and Trigger OUT digitalized by a modified V791;

• PMT trigger distributed to V816 module.

PMT

V789

LTCU

V791Ind Coll

IN IN IN IN IN IN IN IN

OUT OUT OUTOUT OUTOUT OUTOUT

IN

OUT

IN

Analog OUT

V816

trigger

PC (RS232)

OUT

IN

IN

Modified V791


Test Results

Problems Solutions

High frequency noise on input signal

Band-pass filter

(f-3dBH = 2 MHz , f-3dB

L = 1 kHz);

Offset for negative input isn’t a stable solution

Inverter amplifier (G=1) in the input stage;

More than 20mV white noise

New pcb (with 8 layers) and EM/RF screening

Not stable DAC threshold

Stable VREF circuit


LTCU prototype v2.0

Power supply an filter

Input stage (for one channel)

or

IN

Band-pass filter Selectable inverter (G=1)

VTest

VTH

OUT

IN

VTH

DAC (for one channel)

VREF

VREF for DAC

Filter for low noise performance

Stable 259mV tension circuit

VREF

EM/RF Screening for input stage


PWR and GND distribution for LTCU v2.0

±5A, AGND (V791 preamp. stage)

+5A1, AGND1 (V791 mux stage)

VCC, DGND (V791 digital stage)

Four GND and two PWR planes

The second trigger level

Trigger Control Unit

Preliminary design


TCU Features

• ≥1 boards per chamber (depending on segmentation)• VME standard• checks Majority, 2D/3D Pattern logic conditions• event is labelled according to topology• Each TCU module receives as input

– Naws signals from the 20 AWS-LTCU boards of a chamber– Npmt signals from PMT-LTCU – Next from external (spectrometers, beam, ...)

• TCU performs coincidences between:– The wire planes (in a 3s time windows)– PMT signals– External requests


Pattern RecognitionNeed to store the evolution in time of the number of fired pixel

A long track fires consecutive pixels (at different times) according to direction. In this case the event is global can be acquired as many local events.

In case of a Supernova burst several pixels could be fired with a big spacing in position and in time.


General Idea on Partial majority

Rack 11Rack 13

• Window runs over the detector

• Majority condition is checked for each window


General scheme of TCU


WiRe coincidences FPGA Features

• The detector is subdivided in four sections• Each section is monitored by a different WR-

FPGA• Each WR-FPGA

– Makes coincidences between wires of different directions

– Checks the occupancy of the section– Detects spots, tracks.


PMT FPGA Features• receives an N bit Word which defines

PMT status• makes concidences between PMT and

wires• makes global trigger proposals

VME interface Features

Directly interfaced to VME CPU. Establishes communication between VME and the rest of the board.


Wire CoincidencesFPGA

preliminary

SYNCBLK

SYNCBLK

ANDBLK

9

13

INA

INB

MASK

9

13

MASK 9

AA

BB

13

A0_B[4:0]

A1_B[5:1]

A2_B[6:2]A3_B[7:3]

A4_B[8:4]

A5_B[9:5]

A6_B[10:6]

A7_B[11:7]

A8_B[12:8]

FLASH

ADR[4:0]

ENC

REG_A

REG_B

REG_C

SUMBLK

VTH

InternalXilinx

Memory

WholeCarpet

Majority

ENCA

ENCA2

ENCA3

MJLOCAL

MJGLOBAL

ADDRESSGENERATOR

FLASH

CLK PIPELINE


A possible implementation: the Uniboard

ICCMASTER

ICCSLAVE1

ICCSLAVE2

ICCSLAVE3

Spartan II

FAUXSpartan II

VME(J2)

Spartan II

VME(J1)

Spartan II

3 3 3

FIFOA

FIFOB

FIFOA

FIFOB

FIFOA

FIFOB

FIFOA

FIFOB

18 18 18 18 18 18 18 18

FF FF FF FF

EF


UNIBOARD

Trigger system for the T600 detector: applications to Supernova detection G. Fiorillo for the ICARUS...

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