other applications and future prospects...iwori courtesy of m. fiorini (ferrara)-32-32 i nput wi...

OTHER APPLICATIONS AND FUTURE PROSPECTS

M. Campbell1, J. Alozy, R. Ballabriga, N. Egidos, J. Fernandez,

E.H.M. Heijne, I. Kremastiotis, X. Llopart, T. Poikela,

V. Sriskaran, and L.Tlustos

CERN, EP Department

1211 Geneva 23

Switzerland

1 Honorary Professor at Glasgow University

Acknowledgements – Collaboration Members

COLLABORATION NAME Medipix2 Medipix3 Medipix4

ASICS

Medipix2

Timepix

Timepix2

Medipix3

Timepix3

Medipix4

Timepix4

Albert-Ludwig Universität Freiburg, Germany X X

AMOLF, Amsterdam, The Netherlands X

Brazilian Light Source, Campinas, Brazil X

CEA, Paris, France X X X

CERN, Geneva, Switzerland X X X

Czech Academy of Sciences, Prague, Czech Republic X

DESY-Hamburg, Germany X X

Diamond Light Source, England, UK X X

ESRF, Grenoble, France X X

IEAP, Czech Technical University, Prague, Czech

Republic X X X



ASICS

Medipix2

Timepix

Timepix2

Medipix3

Timepix3

Medipix4

Timepix4

IFAE, Barcelona, Spain X X

KIT/ANKA, Forschungszentrum Karlsruhe, Germany X

Mid Sweden University, Sundsvall, Sweden X X

JINR, Dubna, Russian Federation X

MRC-LMB Cambridge, England, UK X

NIKHEF, Amsterdam, The Netherlands X X X

Univesridad de los Andes, Bogota, Columbia X

University of Bonn, Germany X

University of California, Berkeley, USA X X X

University of Canterbury, Christchurch, New Zealand X X

Universität Erlangen-Nurnberg, Erlangen, German X X



ASICS

Medipix2

Timepix

Timepix2

Medipix3

Timepix3

Medipix4

Timepix4

University of Geneva, Switzerland X

University of Glasgow, Scotland, UK X X X

University of Houston, USA X X X

University of Leiden, The Netherlands X

University of Maastricht, The Netherlands X X

University of Oxford, England, UK X

University and INFN Section of Cagliari, Italy X

University and INFN Section of Pisa, Italy X

University and INFN Section of Napoli, Italy X

Technical University of Munich, Germany X

VTT Information Technology, Espoo, Finland X

Acknowledgements – Commercial Partners


ASICS Medipix2 Timepix Timepix2 Medipix3 Timepix3 Medipix4 Timepix4

ADVACAM s.r.o., Czech Republic X X X X X

Amsterdam Scientific Instruments,

The NetherlandsX X X X X

Kromek, UK X X X

Malvern-Panalytical, The

NetherlandsX X X X

MARS Bio Imaging, New Zealand X

Quantum Detectors, UK X

X-ray Imaging Europe, Germany X X X

X-spectrum, Germany X

Outline

• Gas detector readout

– GridPix

– GEMPIX

• Visible photon detection

– ARIADNE and TPIX3cam

– Hybrid Photo Detector

• A few examples if other physics experiments

– Breit-Wheeler experiment

– Photon entanglement

– X-ray polarisation measurement

• Collaboration impact

• Personal observations

• Thoughts on future directions

-8- 8

GridPix technology

Pixel chip with integrated Grid (Micromegas-like)

InGrid post-processed @ IZM

Grid set at negative voltage (300 – 600 V) to provide gas

amplification

Very small pixel size (55 µm)

detecting individual electrons

50 µm

dyke

Aluminium grid (1 µm thick)

35 µm wide holes, 55 µm pitch

Supported by SU8 pillars 50 µm high

Grid surrounded by SU8 dyke (150 µm

wide solid strip) for mechanical and HV

stability

Courtesy of P. Kluit (NIKHEF)

-9- 9

Soft X-ray detection - working principle

X-ray photon entering through window

Hitting a gas atomPrimary electrons 1 per 26 eVDrift in E field

Gas amplification andelectron detection

E

In principle photons of energy ~26 eV could be detected. But single pixelscould be mistaken for noise → three pixels close by are probably enough.But photons of 78 eV do not pass through the window.They have to be produced internally.

Courtesy of J. Kaminski (Bonn)

-10- 10

101 Event

55Fe decay: 5.9 keV photon→ ~225 electrons


-11- 11

11Some X-ray Lines

Titanium Ka (4510 eV)Titanium Kb (4932 eV)

Aluminum Ka (1486 eV) Carbon Ka (277 eV)

Copper Ka (8048 eV)


-12- 12

12CAST Experiment

axions/chameleons

photons

CAST-collaboration, CERN

https://www.facebook.com/CASTexperiment/videos?ref=page_internal

The magnet is 10 m long and is cooled down to 1.8 K.In the aperture a magnetic flux of B = 9 T is reached by a current of 13 kA.The support structure can be turned vertically ~±8° and

horizontally ∼±40°.

Sun tracking lasts 2×1.5 h/d (Sunrise & Sunset).

DecommissionedLHC-magnet ispointed to the sun.Axions and chameleonsproduced in the Sunconvert into X-rayphotons.


https://www.facebook.com/CASTexperiment/videos?ref=page_internal

-13- 13

13CAST Results

Interesting forchameleon search

Interesting foraxion search

Fluorescenceof Argon

Cosmic rays andfluorescence of Copper

Backgroundrejection bylikelihoodcomparing X-rayevents with datataken during run.

Highly ionizing track(background)

X-ray(signal) Courtesy of J. Kaminski (Bonn)

-14- 14

14Large TPC (for ILC) Test Beam Preparations

Some of the challenges are:● LV distribution possibly up to 85 A @ 2.2 V● Cooling● InGrid production● Bonding on boards● Synchronized readout

-15- 15

15Large TPC - Event Picture (I)


-16- 16

16Large TPC - Event Picture (II)


-17- 17

17Timepix3 GridPix – SEM Pictures


-18- 18

Two Micro Pattern Detectors

TimepixGas Electron Multiplier

GEM foil

70 µm 140 µm

4 Timepix

chips

Triple GEM

GEMPix

Tri

ple

GE

MReadout ElectronicsCourtesy of F. Murtas (Frascati)

-19- 19

GEMPix for Hadrotherapy

Gempix Detector (10 cm2 GEM detector read by 55x55mm pixels, 262 000 channels )

- 3D measurements of energy released in water phantom in hadrotherapy treatment facility (CNAO Pavia)

Gempix inside Phantom

Flux 8x106 Energy 332 MeV/u

GEMPix measurements /FLUKA

match within +/- 15%

F.Murtas , M. Silari, G. Stuart,

J.Leidner, M.Ciocca and A.Mirandola

CERN, INFN, UNIPV, CNAO

Journal of Instrumentation 13 (2018) P08009

-20- 20

GEMPix for Radiotherapy

F.Murtas , G. Claps, D. Falco

CERN, INFN, PTV


- 2D measurements of energy released in hadrotherapy treatment facility (Policlinico Tor Vergata Roma)

An optimal accordance between Gempix and gafchromic film is obtained

Real-time measurements with GEMPix allows fast Quality Assurance procedure.

Gafchromic film 10

min

GEMpix, 1 minIntensity Modulated Radiation Therapy

(IMRT)

6 MeV

gamma6 MeV

gamma

G.Claps PhD Thesis, University of Tor Vergata, Rome (2015).

-21- 21

GEMPix for Radioactive waste (55Fe)

5.9 KeV

3 KeV

BKG

A GEMPIX detector with

an active area of 3x3 cm2

Waste

sample

Single X-ray can be detected with high rejection respect gamma background (60Co)

The measurement procedure done with GEMPIX have a sensitivity of 10 Bq/g in 2 hour

The radiochemical analysis is more expansive and needs more time

F.Murtas , M. Silari, G.Stuart, J. Leidner

CERN, INFNNucl.Instrum. Methods A, vol. 849, pp. 60-71, 2017

-22- 22

GEMPix for Fusion Research Tokamak

F.Murtas , G. Claps, D. Pacella

CERN, INFN, ENEA


- X-ray Plasma images during shots at KSTAR Tokamak (Korea) Detector size : 2.8×2.8 cm2

Spatial resolution

GEMpix pixel: 512×512

Area of covered plasma: 60.6×60.6 cm2

Therefore spatial resolution is ~ 1 mm

Time resolution :

Data acquisition time: 0.01 s

Data writing time: 0.5 s by frame

Therefore total time resolution is > 0.5 s

ToT

mode

ToT

mode

GEMPix detector showed its potentiality for Tokamak plasmas X-ray monitor (higher spatial resolution)

Measurements in progress also with laser facility at ABC in Frascati and Eclipse in Bordeaux

Review of Scientific Instruments 87 (2016) 103505.

-23- 23

laser pulses:

• laser wavelength = 800 nm

• Cu - 170mJ at 100 kHz, τ = 39 fs

• Ni, Fe, 175 mJ @ 100 kHz, τ = 39 fs

• Focal spot 10 um (at target)

Gain Voltage @ 900 V

Al 10 um no filter

no filterAl 20 um

Al 40 um

Cu 30 umAl 10

um

no filter

Al 40

um

Al 20

um

no filter

Cu 30

um

140 140

We tested successfully the GEMpix

to different energies and photon

fluxes changing targets (Cu, Ni, Fe,

Ti, Mylar) and using a set of filters.

Cu

targ

et

filter responses

mask with different filters

GEMpix for Fusion : Laser Facility

F.Murtas , G. Claps, D. Pacella

CERN, INFN, ENEA

GEMPix

Journal of Instrumentation 11 (2016) C03022–C03022.

Outline


– GridPix

– GEMPIX











-25- 25

ARIADNE Design

500µm

- 1500L Cryostat

- 53x53x80 cm3 active

volume

- Self contained

cryogenic recirculation

and purification system

- High voltage

feedthrough

- Nominal Electric field

0.5 kV/cm

- 4x Andor EMCCDs

- 4x 8” Hamamatsu PMTs

- 16 pad segmented

THGEM

- Nd:YAG laser calibration

system

Beam window detail

THGEM detail

EMCCDsLASER

THGEM

Field

Shaping

Rings

Beam

window

PMTs

HV FT

Turbo

pump

Courtesy of K Mavrokoridis | ARIADNE

-26- 26

ARIADNE Operation

- Two-phases, Liquid and Gas Argon

- Particles interact with argon creating detectable scintillation

light and ionization (charge)

Innovation of ARIADNE:- THGEM in gas phase amplifies drifted charge by up to 100

times

- This creates secondary scintillation light (S2) that we

photograph with high sensitivity cameras (EMCCDs)

Benefits over previous charge readout techniques:- High resolution — each EMCCD sensor is 1024x1024 pixels

(run with 4x4 binning ≈ 1mm resolution).

- Sensitivity to low energies — gain generated in the THGEM

and the single-photon sensitivity of the EMCCDs.

- Very low noise — EMCCDs are decoupled from detector

noise sources.

- Ease of access — EMCCDs and future optical readouts can

easily be swapped in and out, even during cryogenic running.

- Cost efficient (No need for thousands/million charge

channels used in previous charge readout technology)

Large LAr Detectors have many challenges, that

ARIADNE addresses with innovative approaches


TPIX3CAM readout from ASI


TimePix3 camera setup @ ARAIDNE test beam

o A TimePix3 camera was mounted

on the ARIADNE prototype TPC

we have in Liverpool.

o The TPC was filled with 100mb

CF4 and the detection/operation

principle is the same like in

ARIADNE. The light detection

efficiency has been directly

compared to the EMCCD camera

and found to be very similar.


Movies for ARIADNE alpha tracks

Time over Threshold Time of Arrival


see CERN EP Detector seminar 14th June https://indico.cern.ch/event/823867/

https://indico.cern.ch/event/823867/

-30- 30

Optical imaging tube

Optical imaging tube fabricated in-house: ASIC embedded

in vacuum tube (J. Vallerga, A. Tremsin et al., 2008)

)30

Multi-alkali photocathode

S20

Quantum Efficiency:

maximum 4% at ~400 nm

Chevron MCP pair

Based on Medipix2 ASIC

256×256 pixels

Only photon counting

No timing information

Successful sealing of the tube

CMOS ASIC survived high-temperature processing steps

Proof of concept Courtesy of M. Fiorini (Ferrara)

-31- 31

Quad-Timepix imaging tube

• Prototype optical photon counting

imaging tube (J. Vallerga, A.

Tremsin, T. Michel, J. Alozy, M.

Campbell, 2009-13 development)

– 4×Timepix (4×256×256 pixels)

– Time-tagging of events (10 ns) or

Time-over-Threshold measurement

– 50 mm square tube (Photonis)

– Bi-alkali photocathode (22% QE at

400 nm)

– Chevron MCP pair (25 μm pores)

– 4.5 mm photocathode to MCP gap

• 165 μm FWHM position resolution

iWoRi

Courtesy of M. Fiorini (Ferrara)

-32- 32

Input window, with internal photocathode coating

Ceramic carrier board

Pixelated CMOS anode

Heat sink

MCP stack

PCB PCB

Socket for

pin connectors

Socket for

pin connectors

Timepix4-based vacuum tube design

• Detector side-view

iWoRiD

3D rendering


-33- 33

Electronics and DAQ

• Front-end electronics architecture is

data driven

– 64 bit for each pixel hit

– 80 Gbps maximum data rate for a

total rate of 1.2 Ghits/s

• Flexible design: electro-optical

transceivers will link the ASIC to an

FPGA-based board for the

exchange of configuration and the

collection of event data

– FPGA far from detector

201833

The FPGA will perform serial decoding and send the data

directly to a PC for storage using fast serial data links


Outline


– GridPix

– GEMPIX











-35- 354/30November 28th 2018, CERN

The linear Breit-Wheeler process

• Fundamental QED process; Two photons annihilate to produce an electron positron

pair - Most simple process of creating matter from light

• First proposed by Breit & Wheeler in 1934, but never been directly observed in the

lab

• Reverse process of electron positron annihilation

Breit & Wheeler, Phys. Rev. 46, 1087

(1934)

Cross Section peaks at just over 10-29 m2

Threshold: s > 1

Center of Mass

energy:

𝑠 =𝐸1𝐸2

2𝑚2𝑐41 − 𝑐𝑜𝑠𝜃

𝐸1𝐸2 > 0.511 MeVFor head-on:

..

.

Courtesy of B. Kettle (Imperial College)

-36- 367/30November 28th 2018, CERN

Possible Breit-Wheeler experiments

O. Pike et al., Nature Photonics 8 (2014)

Requires:

• High energy e- beam

• Bright X-ray bath

(𝐸1) (𝐸2)


-37- 3713/30November 28th 2018, CERN

The experiment setup

15J, 40fs laser

pulse

15J, 50ps

laser pulse

LWFA

gas

cell

Bremsstrahlung

gamma converter

Gamma ray

detector

(CsI crystals)

X-ray field (~keV)x2 Timepix3

detectors

Collimat

or

Removal

magnet

1st

Analyser

magnet

2nd Analyser

magnet

Vacuum

chamber wall

Shielding


-38- 3827/30November 28th 2018, CERN

Timepix3 preliminary results summary

• Dominated by particle hits as opposed to gamma photons

• Tungsten blob (simulated signal) shots show different cluster statistics to those of Nulls shots and No-collimator (increased noise) shots.

• If we know the “signature” of real signal, a discard criteria could be used?

• Lower background than expected? On average 3-4 noise hits.

• Approximately 300 null shots and 300 data shots.

• For 95% confidence using 300 shots; with a background of 2 hits per

shot, should be able to see 0.4 BW per shot.

• Blinding data to improve quality of results – limiting access to ”Data”

shots and relying on calibration shots.


-39- 39

No coincidence

28 mmnon-linear

crystal

Pump: laser starts HPD

Idler:

Photodiode

(APD) stops

Timepix

Signal:

HPD in

ToA-mode

measures

timestamp

Detecting entangled photons with Timepix-HPD

39Courtesy of T. Michel (Erlangen)

-40- 40

In coincidence with idler

photon at APD

non-linear

crystal

Pump: laser starts HPD

Idler:

Photodiode

(APD) stops

Timepix

Signal:

HPD in

ToA-mode

measures

timestamp

28 mm

Detecting entangled photons with Timepix-HPD

Courtesy of T. Michel (Erlangen)

-41- 41

Absolute calibration of the QE of the HPD


-42- 42

Measurement linear x-ray polarisation with Timepix using

photoeffect

Polarized irradiation

E

Unpolarized irradiation

Asymmetry between

double-hits along

rows to columns

Orientation of the detector

Plane of polarization


-43- 43

Compton

electron

(1st hit)

Compton

photon

(2nd hit)

fE

Catch the Compton scattered x-rays

Nu

mb

er

of

eve

nts

Scattering angle f [°]

Measurement linear x-ray polarisation with Timepix using Compton

scattering


Outline


– GridPix

– GEMPIX











Measuring our scientific impact (1)

Measuring our scientific impact (2)

Outline


– GridPix

– GEMPIX











-48- 48

Some personal observations on ASIC design

• In our mixed mode designs the effort has gone from 80-90% analog front ends to

80-90% digital

• We’ve been confronted by digital errors over the years which explains our (well,

Xavi’s) strong insistence on careful design verification and the digital on top

design flow

• That being said analog design isn’t getting easier – quite the contrary with falling

Vdd and low headroom. Also, due to charge sharing in the sensor, we require

clever analog circuitry to avoid sub-threshold loss in spectroscopic imaging

applications.

• We also have to remember that our designs are (highly) unusual and that can

cause matching and yield challenges

Outline


– GridPix

– GEMPIX











-50- 50

So, what’s next after Timepix4/Medipix4?

• The cost (in Dollars and in time)

of developing these chips is still

increasing but technical

advances will require the use of

new processes

• As a community we are still far

from being done with Moore’s

law

• That being said at some point

industry is likely to ‘morph’ into

3D stacking as following Moore’s

law becomes prohibitively

expensive.

At CERN we

are designing in

65nm CMOS

-51- 51

What about X-ray radiology?

More sophisticated ‘washing machines’?

-52- 52

What about X-ray radiology?

Or collaborating robots in the medical centre…

-53- 53

Will monolithic detectors supersede hybrids?

• The monolithic pixel approach has clear benefits compared with

hybrid (no bumping -> lower cost, reduced Cin -> lower

noise/threshold) in tracking applications.

• I believe they will have a major impact in High Energy Physics

experiments but maybe to begin with more in replacing legacy

projective tracking systems with moderate hit rates

• However, hybrid pixel detectors (using bump bonding or wafer

stacking) will continue to be required in very high rate environments.

(Management: please don’t put all your eggs in one basket!)

• Also, by their nature and as we‘ve seen today, hybrid pixels are

significantly more flexible

-54- 54

Conclusions

• Hybrid pixel detectors were developed as tracking detectors of LHC.

• The Medipix2 and Medipix3 Collaborations have taken the technology into many other fields

thanks to a science-driven collaborative approach

• Like all successful developments we had to overcome significant technical challenges along the

way and the design team is greatly indebted to the support of our collaboration partners

• The technology has led to a number of high-tech start ups to develop in CERN member states

and elsewhere.

• Many novel scientific applications and experiments have been made possible by the very generic

architecture of the Timepix and Timepix3 chips. This helps contribute to a diverse physics

programme.

• CERN experiments have benefitted directly from use of our chips and indirectly from the

development of technologies and know-how which can be applied to HEP experiments.

• The Medipix4 Collaboration is developing high resolution pixel readout chips which can be tiled

on 4 sides.

-55- 55

Final thoughts

• As Mark Twain once said, “The reports of my death are greatly exaggerated”.

I believe that hybrid pixel detectors would concur!

• As design efforts and masking costs shoot up I believe our collaborative

model for ASIC design will become more common.

• Knowledge Transfer is not a one way street from science to industry. We can

(and do) learn and benefit from each other. Industry also plays a key role in

making our technology available to other scientists

• If I had to hazard a guess: Timepix5/Medipix5 will have more and smaller

pixels with even better timestamping. The question is: can we learn from other

fields (such as AI) how to do local data processing and stem the data deluge?

-56- 56

Thank you for your attention – and for 20 exciting years!

other applications and future prospects...iwori courtesy of m. fiorini (ferrara)-32-32 i nput wi...

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