19 November 2009 Christian Irmler (HEPHY Vienna) APV25 and Origami Scheme 4 th Open Meeting of the...

19 November 2009

Christian Irmler (HEPHY Vienna)

APV25 and Origami Scheme

4th Open Meeting of the Belle II Collaboration

2Christian Irmler (HEPHY Vienna)19 November 2009


Origami Module Status

Beam Test Performance

Origami Cooling

Hybrid Cable Length

Summary & Outlook





Origami Cooling

Hybrid Cable Length

Summary & Outlook



Belle-II SVD Layout

• Proposed SuperSVD geometry • Central pixel double-layer using DEPFET• 4 strip layers of 6” DSSDs• Every sensor is read out individually to maintain high SNR

– red: Origami chip-on-sensor concept– green: read out by conventional hybrid (from side)

0

0

10

1+23

45

6[cm] layers

[cm]

20

-10-20-30 10 20 30 40

Double-layer of DEPFET pixels

4 layers of double-sided strip sensors



Origami Concept

Total material budget: 0.6% X0

(cf. 0.48% for conventional readout)APV25(th inned to 100µm)

zylon ribcooling pipe

DSSDRohacellKapton

side view

• Thinned readout chips (APV25) on sensor

• Strips of bottom side are connected by flex fanouts wrapped around the edge

• All readout chips are aligned single cooling pipe

• Shortest possible connections high signal-to-noise ratio

zylon rib

APV25 cooling pipe

3-layer kapton hybrid

integrated fanout(or: second metal)

DSSD

single-layer flex wrapped to p-side



• Status at 3rd B2GM: Sensor of first module was broken during bonding– A bug in the bonding program was identified as reason for the accident– Wrong bonding height for sensor

• We started to build a new Origami Module • Delivery of new hybrids again delayed• Thus we used the remaining hybrid of the first batch• Successfully repeated assembly steps 1 to 7 as shown in B2GM

in July 09 (gluing and bonding of fanouts, hybrid, APVs, …)

• But now the bondability of the integrated pitch adapters of the hybrid was checked in advance.

• Wire bonding between sensor and integrated pitch adaptor successfully performed

Progress since last Belle II Meeting (July 09)



Module Assembly Continued

• Bending & Gluing of fanouts– Most complicated task?– Using positioner equipped with

a custom tool – Easier than expected– Allows precise positioning

w/o damaging underlying wire bonds

• Wire bonding between APVs and pitch adaptors

• Attaching cooling pipe– Thermally conductive paste– Electrically isolating pad

between APV and pipe



Final Origami Module

• Top and bottom side Origami concept• Prototype completed beginning of August 2009





Origami Cooling

Hybrid Cable Length

Summary & Outlook



Beam Test Setup

• CERN SPS beam line Aug. 09• 120 GeV π+ / p / K+ • Cooling: 13 °C water

cooling system

beam

• Origami Module• Together with other types of

Belle DSSD prototype modules



Beam Test Results

• Origami Module has been tested for several hours • Good performance w and w/o cooling (13 °C water)• About 80 GB data recorded• Analysis is in an early stage results preliminary• Benefit of cooling: ~ 10% higher SNR

120 GeV/c π+/p/K+ w/o cooling cooling (13° water)

p-side n-side p-side n-side

Average cluster width 2.2 1.8 2.2 1.8

Cluster SNR 11.5 16.7 12.8 18.5

• Cluster SNR = strip_signal / ( sqrt(cluster_width) * noise_avg)• ~10% higher noise compared to 2008 beam test for all modules

(ground loop in the front-end and / or HV supply?) • Hence SNR of all modules is slightly worse than expected



Beam Test Results – Hit Time Reconstruction

• Time resolution achieved in beam tests with several different types of Belle DSSD prototype modules (covering a broad range of SNR)

Time Resolution vs. Cluster SNR

0

1

2

3

4

5

6

7

5 10 15 20 25 30

Cluster SNR [1]

trm

s [n

s]Previous beam tests

SPS 09 beam test

Log-Log Fit

(TDC error subtracted)

Origami Module

• SPS 2009 data matches previous beam test.

• 2...3 ns RMS accuracy at typical cluster SNR(15...25)

• Origami shows similar precision like other modules





Origami Cooling

Hybrid Cable Length

Summary & Outlook



Origami Cooling – Intention

• Learned from Beam Test:– Cooling with water of 13°C ~10% higher SNR

– Temperature inside module was not measured unknown conditions

• Source tests with temperature sensors mounted on the cooling pipe of the module

• Cool down to sub-zero temperatures– Needs flushing with dry air to avoid condensation

• Which SNR can be achieved?



• 3 temperature sensors on cooling pipe• One sensor to measure air temperature

Origami Cooling – Setup 1

liquid flow direction



Origami Cooling – Setup 2

air dehumidifier

chiller

pipes (uninsulated)

• Cooling liquid: water with glycol as anti-freeze protection

• Cooled the liquid down to -20°C• Due to lack of insulation and the thin pipe,

only -8.5°C could be reached at the module (first temp. sensor)

• Achieved liquid flow: ~1 ml/s

dry air flushing

connection to Origami cooling pipe



Origami Cooling – Results• As expected significantly better SNR with cooling• Relative improvement: ~ 20% @ -8.5°C • Corresponds to CMS studies• Some APV settings have to be adapted for low temperature

operation to avoid increase of power consumption (not yet done, but recommended by Mark Raymond)

Temperature at first thermal sensor Cluster SNR

improvement referred to

warm

[°C] p-side n-side p-side n-side

67,70 11,03 14,61

8,70 12,15 17,20 18% 10%

-8,50 13,25 17,73 21% 20%





Origami Cooling

Hybrid Cable Length

Summary & Outlook



Intention

• There is only little space for DOCK boxes inside the detector• 1902 APVs ~ 10 DOCK boxes per side required• Approx. twice than in SVD2 not enough space • Radiation dose unknown supposedly too high

• Can DOCK boxes be placed outside of the detector?• Determine maximum cable length between hybrid and repeater • Comparative measurements with long and short cables

– long: 8.7m longest available in lab– short: 1.8m currently used for prototype modules



Cable Type

• CERN 04.21.21.E • 3M type: 79992-25P-270A• Fine pitch, twisted pair with flat region

every 30 cm• Halogen free



Pulse Shape

• ADC delay scan of APV25 tick mark

• Effect of bandwidth limitation of long cable

• Similar effect was observed with long CAT7 cables

• Solved by AD8128 equalizer chip on FADC board

• Can this chip also compensate the effect of the hybrid cable?

• Tried to adjust AD8128 parameters

short (1.8m) cable long (8.7m) cable



Pulse Shape with Improved Compensation

• Complete compensation of bandwidth effects when modified AD8128 parameters are used

• But now minor negative reflection of tick mark is visible

• Needs adjustment of cable termination on REBO

pulse shape with compensation



Voltage Drop

• Hybrid equipped with 2 APVs, both enabled (bias generators turned on)

• Voltages measured on the hybrid• Voltage drop is too high, even though APVs are working well

• Possible solutions:– Remote sensing requires overvoltage protection on hybrid– Thick supply cables and a junction box close to the front-end– See following talk of Markus Friedl

V_hybrid [V] V_drop [mV] I_supply [mA]

+1.25V 1.10 150 110

+2.5V 2.35 150 220



Source Measurement

• JP_Module (SVD2.5 sensor) equipped with 4 APVs used• Only one chip was enabled (bias generators turned on) in order to

reduce voltage drop• Proper signal histogram• Minor, but tolerable decrease of signal-to-noise ratio of about 3%

• Probably caused by voltage drop comparative measurement with short cable but lowered supply voltage (run003 and run004)

• 1.09V and 2.38V instead of 1.25V and 2.5V, respectively• Higher SNR measured w reduced LV effects below repeat accuracy

run condition signal [e] noise [e] clwid SNR Delta

run001 short, normal 20274 994 2.49 12.93 -3.41

run002 long cable 21310 1086 2.47 12.49

run003 short, normal LV 20231 1055 2.5 12.13 1.75

run004 short, reduced LV 20376 1030 2.57 12.34



Cross Talk Measurement - Setup

• Comparison separated and bundled cables (1.8m = short)

• Cable of DUT is placed between the cables of two other modules

• Cables are stacked at all 5 flat regions

• Overlap = 5 x 40 mm = 200 mm



Cross Talk Measurement - Method

• Internal calibration with huge signal on the two modules which are not DUT

• Pulse height ~ 10 MIP• Pulse generator of DUT

disabled• Measurement of induced

signal



Cross Talk Measurement - Response

• Response of separated (left) and bundled (right) cables, respectively• Observed very weak induced signal• X-talk is in much lower than noise (<1 ADC count or <0.2% of pulse

height) negligible

separated cables bundled cables





Origami Cooling

Hybrid Cable Length

Summary & Outlook



Summary & Outlook

• Origami Module:– Successfully built the first Origami Module Prototype– Module has shown excellent performance at the beam test– Design of 6” Origami hybrid has been started recently– We build a complete ladder of the outermost SVD layer next year

Mechanics design see talk of I. Gfall

• Cooling:– SNR can be improved by ~20% using liquids @ sub-zero temperatures– Thin pipe: How can we ensure sufficient flow rate?– Common cooling system for PXD and SVD?

• Hybrid cables:– Cables with ~8.7m tested tolerable SNR decrease of ~3%– No cross-talk measured– Repeater can be placed outside the detector see talk of M. Friedl



Thank you for your attention



Backupslides



Calibration Curve

• Proper calibration curve with long cables• Similar pulse shape and height



Pulse Shape with Compensation

• zoomed tick mark w/ long (8.7m) cable

Date post:	16-Jan-2016
Category:	Documents
Upload:	clarence-malone
View:	214 times
Download:	0 times

19 November 2009 Christian Irmler (HEPHY Vienna) APV25 and Origami Scheme 4 th Open Meeting of the...

Documents