TileCal Electronics

A Status ReportJ. Pilcher

17-Sept-1998

17-Sept-98

Outline A status report on the front-end and digitizing

electronics Overview of requirements Development status July ’98 test beam results

Barrel module 0 equipped with 2 superdrawers– 90 channels

First system tests with “in-drawer” digitizers

17-Sept-98

REQUIREMENTS Process 10,000 PMT signals Located in 256 electronics drawers

Up to 45 PMT/drawer Each module self-contained with own electronics

17-Sept-98

REQUIREMENTS

Performance 16 bit dynamic range

Up to 2 TeV in single cell Must see muons

– Calibration and monitoring– Enhance muon ID

Readout resolution should not degrade calorimeter energy resolution

Calorimeter resolution > ~2% Need readout resolution of a few percent in each cell Jet populates many channels

– averaging effects

17-Sept-98

REQUIREMENTS

In situ calibration Gives readout conversion factor (pC/count) Measures linearity Calibrates source integrator

Slow integrator for PMT current

LVL1 trigger tower sums

17-Sept-98

ORGANIZATION 3-in-1 Card

One per PMT Plugs into PMT anode

Near-ideal current source Pulse shaped signals to

digitizers Integrator for source calibration

and monitoring min-bias current

Gain switching Output gating

Charge injection for electronics calibration

LVL1 Trigger output Gated

17-Sept-98

ORGANIZATION Mother Boards

set of 4 in tandem per drawer

Services and control signals to 3-in-1

Digitizer Boards set of 4 (or 8) per drawer

Connections to drawer TTC fiber S-LINK fiber D.C. Power CANbus

17-Sept-98

Bigain pulse shaper 7-pole Bessel filter (purely passive)

Exploit current source nature of PMT No noise, no power Very linear

Clamping amplifiers and drivers Gain ratio 64:1 for dual 10-bit ADCs

3-in-1 Card Status

17-Sept-98

Output pulse to digitizers Low Gain (1 GeV/mV)

Full scale signal

High Gain (16 MeV/mV) Muon signal

3-in-1 Card Status

Low Gain Output1000 GeV input(full scale)

-0.2

0

0.2

0.4

0.6

0.8

1

-100 -50 0 50 100 150 200 250 300 350 400

Time (ns)

High Gain Output200 MeV input(muon signal)

-0.005

0

0.005

0.01

0.015

0.02

0.025

-100 -50 0 50 100 150 200 250 300 350 400Time (ns)

17-Sept-98

Linearity and calibration Residuals < 1 count over full dynamic range

3-in-1 Card Status

±1 count

±1 count

17-Sept-98

Source integrator Essential for Cs calibration and monitoring of

calorimeter See preceding talk

Cs calibration has short-term reproducibility of ~ 0.1%

Should be matched by electronics stability

3-in-1 Card Status

17-Sept-98

independent readout for each drawer ADC board + CANbus

Multiplexed to individual 3-in-1 cards

Integrator Readout Status

17-Sept-98

Source Integrator Stability better than 0.1% over 2 months (calibrator

+ integrator)Integrator Stability (Drawer A)

-2.0

-1.0

0.0

1.0

2.0

0 10 20 30 40 50 60 70 80

Time (days)

Gain 1Gain 2Gain 3Gain 4Gain 5Gain 6

Integrator Stability (Drawer B)

-2.0

-1.0

0.0

1.0

2.0

0 10 20 30 40 50 60 70 80

Time (days)

Gain 1Gain 2Gain 3Gain 4Gain 5Gain 6

17-Sept-98

Digitizer Status Partially equipped Barrel Module 0 (30

channels) in July ’98 First system test of “in-drawer” digitizers

Two 10-bit 40 MSPS ADCs per channel High gain scale 0 - 16 GeV (16 MeV/count) Low gain scale 0 - 1000 GeV (1 GeV/count) Commercial components

TTC input on optical fiber 40 MHz clock, LVL1 accept, digitizer control data

17-Sept-98

Digitizer Status Pipeline delay via custom ASIC

Digital memory unit (DMU) Originally developed for PHENIX TEC

Output via optical S-LINK Read with optical LDC/PMC, RIO processor

17-Sept-98

July ’98 Test Beam Results Laser calibration

Measure linearity and stability of PMT and electronics

3 PIN diodes to monitor laser

17-Sept-98

July ’98 Test Beam Results Digitized signals

More pedestal noise on high gain channel Digitizing clock not synchronized to beam

17-Sept-98

July ’98 Test Beam Results Pedestal Noise

High Freq. Noise

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20 25 30Digitizer Number

High GainLow Gain

Low Frequency Noise

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20 25 30

Digitizer Number

High Gain

Low Gain

Noise for high gain branch ~ 1.1 counts Corresponds to ~ 0.4 photoelectrons in PMT (17 MeV) SPICE simulation predicts 1.2 counts

Noise for low gain branch ~0.5 counts SPICE simulation of 3-in-1 card predicts 0.3 counts Digital noise < ~ 0.4 counts

17-Sept-98

July ’98 Test Beam Results Muon response for the 3 sampling depths (=90)

Pedestal superimposed Using “signal” from empty events Width reflects energy algorithm as well as electronics

– 10 digitizations used for each measurement (not optimized)

Muon signal well resolved from pedestal

17-Sept-98

July ’98 Test Beam Results Electron response

Most energy in a single cell Channel-to-channel intercalibration less important

Calibration not yet available 50 GeV and 100 GeV electrons

17-Sept-98

July ’98 Test Beam Results

Use e- response to measure readout resolution

δE

E=

23%

E⊕ 0.5%⊕

a

E

Fit for a reflects readout resolution and energy algorithm

e - Energy Resolution

0

2

4

6

8

10

10 60 110 160 210 260

Energy (GeV)

'98 Measurements'97 MeasurementReadoutSamplingConstant TermTotal

17-Sept-98

Energy resolution gives readout resolution of 0.5 counts/sample

ADC quantization error noise ...

Noise study gave 0.5 counts

Well understood result Readout will not limit

resolution of hadronic calorimeter

July ’98 Test Beam Results

17-Sept-98

July ’98 Test Beam Results

Pion energy resolution from test beam Under analysis Needs cell-to-cell intercalibration

Electron shower largely contained in single cell

17-Sept-98

Future Planning Radiation hardness tests this fall Design review this fall Electronics PRR spring ’99 3-in-1 production to start spring ’99 Version 2 of digitizer to be demonstrated

spring ’99 Final electronics needed for module

calibration in ’00, ’01, ’02 Finish production of electronics in ’02

Before start of installation

17-Sept-98

Conclusions TileCal electronics shows good performance

Achieved required dynamic range with linear system

Very low system noise Electron energy resolution used to measure

readout resolution First successful tests of “in-drawer” digitizers

No unexpected problems so far Still a lot of work to do!

Expect to start production on schedule