SiPM readout for ECALSiPM readout for ECAL

Guido.Haefeli@epfl.ch ,EPFL Lausanne

PEBS ECAL meeting , Lausanne 30. April 2009

OverviewOverview Power consumption of the ECAL SPIROC dynamic range USB readout New SPIROC card for ECAL New USB board for PEBS DAQ

Power consumption for the Power consumption for the ECALECAL The power consumption estimates are based on the values measured at

AMS2. Note that the electronics was developed with a lot of effort to reduce power.

The latest generation of CPLD (Altera MAXII G) used at the Front End Hybrid (FE-Hybrid) and the low power FPGAs (for example Altera Cyclone III) for the Data Reduction Modules (DRM) are very well suited for our application and promise low power consumption.

Estimate for the DRM consumption of 1.2mW per channel.◦ Note that for a DRM with 8 ADCs can readout for example 8x 6x36= 1728 channels for the

ECAL or 2048 channels for the fibre tracker a total of only 3.6 W is assigned to the DRM board

◦ The DC-DC and bias power was measured for AMS2 at 2.2mW per channel.

For the SPIROC Waclaw has measured 10mW per channel without power saving and 3-5mW per channel if as much as possible of non-used parts are switched off.

Summary: 120 FE-Hybrids * 36 channels = 4320 channels◦ Power for FE-cards 4320 x 10mW = 43 W◦ Power for DRM 4320 x 1.2mW =5.2 W◦ Power for DCDC 4320 x 2.2mW =9.5 W Total: 57.7 W

Note on the dynamic range of the SPIROCNote on the dynamic range of the SPIROC

In the data sheet of the SPIROC is stated that the dynamic range of the SPIROC is 1-1000pe !

The dynamic range of the chip for a constant setting as it is intended be used for the ECAL is at most 1-100pe ◦ Only if auto gain selection is used the dynamic range is increased by a

factor 10. The low and high gain are automatically selected. In the PEBS ECAL we do not have any information about which mode was selected because the digital data is not readout.

Waclaw has seen in his tests that above 35pe a important dead time is occurring (order of ms). This is due to some saturation in the chip. Useable dynamic range even smaller??

SPIROC overviewSPIROC overview

50 -100ns

50-100ns

Gain selection

4-bit threshold adjustment

10-bit DAC

15ns

DAC output

HOLD

Slow Shaper

Slow Shaper

Fast Shaper

Time measurement

Charge measurement

TDC ramp

300ns/5 µs

12-bit WilkinsonADC

Trigger

Depth 16

Depth 16

Depth 16

Common to the 36 channels

8-bit DAC0-5V

Low gain Preamplifier

High gain Preamplifier

Analog memory

15pF

1.5pF

0.1pF-1.5pF

Conversion 80 µs

READ

Variable delay

0.1pF-1.5pF

IN

Discri

Gain

Flag TDC

Analog output

Measurement from Orsay IMeasurement from Orsay I

jeudi 10 janvier 2008 Ludovic Raux - Calice electronics meeting - SPIROC ASIC measurement 6

680fC ( ~4 pe @SiPM gain=106) in SPIROC

Charge measurement

Auto trigger

High gain channel output

Vout=30mV

Noise=1mV

Gain=45mV/pC

pe/noise~7 (expected ~11)

Set up:

Cf=400fF

Tau=50ns

7

Preampfier measurementPreampfier measurementVout=f(1/Cf), Qinj=680fC, tau=25ns

0

5

10

15

20

25

30

35

40

45

0 0.001 0.002 0.003 0.004 0.005 0.006

1/Cf (1/fF)

Am

pli

tud

e (m

V)

Série1

Vout=f(1/Cf), Qinj=680fC, tau=175ns

0

5

10

15

20

25

30

35

0 0.001 0.002 0.003 0.004 0.005 0.006

Amplitude Vout (mV)

1/C

f (1

/fF

)

Série1

Qinj= 680fC (~4pe at SiPM gain of 106)

Cf (fF)noise RMS(mV)

25snoise RMS (mV) 175ns

Vout (mV) 25ns

Vout (mV) 75ns

200 1.2 2.2 42.6 32.5

400 1.0 1.3 26.3 18.7

600 0.92 1.15 18.8 13.2

800 0.9 1.0 13.9 10

1000 0.9 0.95 11.4 7.8

1200 0.9 0.9 9.6 6.6

1400 0..9 0.9 8.2 5.6

USB readoutUSB readout2 boards now used in EPFL SiPM testing3 boards delivered to Aachen last week, VA32 and

SPIROC card readout was successfully tested in internal and external trigger mode.

Small webpage made available to access design resources◦ http://lphe.epfl.ch/tell1/usb_board/◦ User manual written◦ C-code version 1 released◦ VHDL (firmware) version I released

Some fixes in c-code needed and root file writer will be implemented for version 2.

Power supply still not available for about one more month.

USB readout for PEBSUSB readout for PEBSA USB board made for low power and with

crate power supply could be made for the readout of the complete PEBS detector.

A USB Hub (USB 2.0 provides 480Mbit/s) data bandwidth could be used for data collection to a PC.

Measure the performance with the current USB boards and a Hub to understand if this is a feasible option.