[email protected] ECFA Meeting, Valencia – November 8, 2006 1
First TimePix tests First TimePix tests
at CERNat CERN
David Attié
ECFA Meeting – Valencia – 8 November 2006
[email protected] ECFA Meeting, Valencia – November 8, 2006 2
Introduction
• TimePix Proposal: November 2004
- develop- produce Medipix2 TimePix- test
• TimePix test at CERN ~ November 2006
11 22 44
55
66
33
55μm
55μm
11 22 44
55
66
55μm
55μm
Medipix2 TimePix
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TimePix measurements
* Chip design was submitted to foundry on the beginning of July * 12 wafers arrived at CERN 2nd week of September
* Modifications in the Medipix readout system (~1 week):
• “Timepix-Medisoft” version of the software
• MUROS2 firmware updated (thanks to Hans Verkoojen, Nikhef)
* Preliminary TimePix characterization has been done on-wafer using the Medipix2 probing card in the DSF clean room facility at CERN
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Test procedures for TimePix
* Alignment monitor (moving platform + microscope) to position the chip
* Readout using probing bench + MUROS2
Classification (A, B, C, …)
* Software used : Medisoft 4.x
• Analogic tests (ANIN)-TOT mode- MEDIPIX mode
• Digital tests using calibration of DACs
* Check the current supply (~200 mA/chip) and ID chip
[email protected] ECFA Meeting, Valencia – November 8, 2006 5
Test procedures for TimePix
* Alignment monitor (moving platform + microscope) to position the chip
* Readout using probing card of Medipix2 + MUROS2
Classification (A, B, C, …)
* Software used : Medisoft 4.x
• Analogic tests (ANIN)-TOT mode- MEDIPIX mode
• Digital tests using calibration of DACs
* Check the current supply (~200 mA/chip) and ID chip
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―PreampOut
Pixel measurement
• From 2 special pixels at the bottom of the matrix we can measure:
- preampOut - discOut- internal Ref_Clk- counter clock
• State Machine of the counter Modes (P0, P1)
- Medipix (0, 0)- TOT (0, 1)- TimePix-1hit (1, 0)- TimePix (1, 1)
work as expected in simulations
• No visible coupling of the Ref_Clk signal into the analog signals (preampOut and discOut)
―Thr
―Shutter
―discOut
―CounterClk
TimePix-1hit mode (P0=0; P1=1) TOT mode (P0=1; P1=0) TimePix mode (P0=1; P1=0)
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0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256
DAC Code
[V]
Preamp Disc
TimePix DACs
• Some DACs show a non-monotonic curve
• Non- Monotonic DACs are:- Preamp- Disc- BufferA- BufferB
• Problem may be related to the latching of the DACs register
• The midrange value (code 01111111=127) is always stable (1 complete wafer)
• These DACs are unchanged under normal operating conditions
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 256
DAC Code
[V]
THL FBK
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TimePix chip classification
Classification of a tested chip:
• Class A: no dead column
• Class B: 1 dead column
• Class C: 2 dead columns
• Class D: more than 2 dead columns
• Class E: bad DACs
• Class F: bad digital test, no communication, etc… dead chip
14 mm
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First TimePix test
Wafer #14: A5FWQTX
Tested by Xavier Llopart (CERN)
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First TimePix test
Wafer #15: AQFWTPX
Tested by: - David Attié (CEA/Saclay) - Uwe Renz (Freiburg)
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Future development
Medipix2/TimePix
Micromegas+
Mini-chamber
SiTPC endplate+
Large Prototype
• 55 m pixels• Direct X-ray conversion• selection of window in energy• 13-bit counter per pixel
• no ExB effect• good for 2-track separation• high gain• very fast electron signal on the anode plane• very small ion feedback in the space cheap• robust and easy to implement
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Next steps
• First test of a Medipix2 + Micromegas in the gas
• Improve the gas mixture (“non-sparking” state)
• Medipix2 TimePix readout chip LP endplate
M. RIALLOT (DAPNIA/SEDI)
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Metallic box of 24 cm x 14 cm x 6 cm size
Box design
M. RIALLOT (DAPNIA/SEDI)
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Mini-chamber for the Medipix2/TimePix chip
Field cage
Box
Micromegasmesh
Medipix2 readout chip
M. RIALLOT (DAPNIA/SEDI)
Windows for X-rays source
Windows for source
6 cm
2.5 cm
Design plan:
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Conclusions
* 2 wafers and half have been tested at CERN
* ~ 50 % of class A ~ 20 % of class B ~ 30 % of class C/D/E/F
* Test to be continued in the next weeks
* First test beam in DESY right now with Medipix/TimePix
* CEA/Nikhef: test in gas chamber in the next months with Medipix/TimePix
NIKHEF Maximilien Chefdeville, Martin Fransen, Harry van der Graaf, Jan Timmermans, Jan Visschers
CEA/Saclay/ David Attié,é, Dan BurkeDAPNIA Paul Colas, Arnoud Giganon,
Yannis Giomataris
Univ. Twente/ Jurriaan Schmitz, Cora Salm,Mesa+ Victor Blanco Carballo, Sander Smits
CERN Michael Campbell, Erik Heine Xavi Llopart
Thanks to:
Wim GotinkJoop RovenkampMarc Riallot