Studies of transition radiation using silicon on a TimePix3 chip: first results and plans

Transcription

1 Studies of transition radiation using silicon on a TimePix3 chip: first results and plans Enrico Jr. Schioppa1 and Florian Dachs1,8 on behalf of Jerome Alozy1, Nikita Belyaev2, Michael Campbell1, Michael Cherry3, Florian Dachs1, Semen Doronin, Konstantin Filippov2, Fabio Gargano4, Erik Heijne1, Serguei Konovalov5, Dimitrii Krasnopevtsev2, Xavi Llopart1, Francesco Loparco5, Valerio Mascagna4, Nicola Mazziotta5, Heinz Pernegger1, Daniil Ponomarenko2, Michela Prest4, Roman Radomskii2, Christoph Rembser1, Anatoli Romaniouk2, Evgeny Shulga2, Serge Smirnov2,, Yury Smirnov2, Mattia Soldani4, Paolo Spinelli, Daria Sergeeva2, Alexandr Savchenko2, Enrico Jr. Schioppa1, Doug Schaefer6, Mikhail Strikhanov2, Alexey Tischenko2, Petr Teterin2, Vladimir.O Tikhomirov, Erik Vallazza4, Martin van Beuzekom7, Bas van der Heijden7, Konstantin Vorobev2, Konstantin Zhukov5 CERN, Geneva, Switzerland MEPHI, Moscow, Russia 3 Louisiana Un., USA 4 Como, Italy 4 Lebedev, Russia 5 Bari Un., Italy 6 Chicago Un., USA 7 Nikhef, Amsterdam, The Netherlands 8 TU Vienna, Austria 1 2

2 What is transition radiation? X-ray Visible Emission angle Ultrarelativistic: ~ 1 1 Highly relativistic particle, gamma~10³ TR yield is low, ~1% detectors are made of multiple layers of radiators TR is in the X-ray range (kev few tens of kev) TR is emitted in the forward direction (few mrad) For a single boundary, intensity ~ gamma l l For multiple boundaries, interference puts a saturation limit at γ sat =0.6 ω1 1 2 l 1 ω1 TR emission starts at a threshold γ sat = c Particle identification in a given gamma range can be achieved by optimizing the radiator parameters c 2

3 TR theoretical spectrum 3

4 Example: the ATLAS Transition Radiation Tracker (TRT) 4 mm Coated Kapton BARREL 50k straws 30 um W (Au coat) ay X-r E PARTICL X-ray Low threshold particle hits High threshold TR hits ENDCAP 320k straws Plots from reference [2] 4

5 Motivation for more studies Electron-hadron separation works only up to ~ 500. At higher values, the TR yield for hadrons approaches the one of electrons At ~ 3x103, the TR yield saturates (need ~ 105 at future colliders and for cosmic rays) Gaseous detectors can be substituted by pixel detectors. These will allow to achieve particle identification by measuring both energy and angular information of TR photons E.g.: QCD measurements at the LHC Hadrons produced as small angles Need to separate p, K and in the 1-6 TeV range E.g. 2: nuclear charge and energy identification in cosmic ray experiments 5

6 Timepix3 Hybrid 1.4 cm x 1.4 cm 256 x 256 pixels 55 um x 55 um pixel size Single photon counting Spectral sensitivity on single quanta For this experiment, 500 um silicon sensor 6

7 The SPS setup in June 2017 Radiator-detector distance = 220 cm PID trigger BEAM Multilayer radiator Helium pipe 10 cm Pixel setup PID 3 cm 6 cm 1 week beam time Other DUTs (not in this talk): Straw detectors Silicon microstrips 500 um Si 3x300 um Si Nikhef Timepix3 telescope, one arm, modified 7

8 Some pictures The Timepix3 telescope and DUT The whole setup, view from upstream 8

9 Concept X-ray PARTICLE X-ray 9

10 ToT calibration Fluorescence (targets Ca, Cu, Zr, Ag) + test pulses *Errors on the mean are very small All pixels calibration curves Single pixel calibration An additional Fe-55 point was taken during the test beam rescale factor of ~8% All pixels resolution curves 10

11 Alignment and tracking Alignment and tracking is done with the Proteus framework [3]. Many thanks to M. Kiehn. RECONSTRUCTED PARTICLE TRACK CLUSTER CENTER 11

12 Event reconstruction GOOD EVENTS = track intercept 12

13 Quantum mechanics at its finest 13

14 Outlook: tracking is not needed 14

15 Very first results THEORY MEASUREMENT ANGLE PROJECTION ENERGY PROJECTION Credit: E. Shulga, Y. Smirnov, A. Savchenko 15

16 Another example 20 GeV electrons Polypropylene 15 um ANGLE PROJECTION ENERGY PROJECTION Ongoing effort to implement full differential TR spectrum in GEANT4 Credit: E. Shulga, Y. Smirnov, A. Savchenko 16

17 Conclusion and plans Transition Radiation Detectors are useful to achieve particle identification For future collider and cosmic ray experiments, TR angular and spectral information must be exploited First tests with a Timepix3 pixel detector have shown encouraging results The analysis of the 2017 data is being finalized, together with the implementation of MC simulations New beam time in June 2018 No need of a telescope Will measure GaAs sensor, for better spectral sensitivity at high energy 17

18 References [1] B. Dolgoshein, Transition radiation detectors, NIM A326 (1993) , [2] ATLAS Collaboration, Inner Detector TDR, Vol. I, 30 April 1997, [3] [4] N. Belyaev at al., Measurements of angular distribution and spectrum of transition radiation with a GridPix detector, Phys.: Conf. Ser , 18

19 Datasets 19

20 Clustering FRONT PLANE 0 Clustering is done with the Proteus framework [3]. PLANE 1 PLANE 2 Many thanks to M. Kiehn. 20

21 Wtf events (just for fun) 21

22 Event selection 22

23 Fiducial volume correction 23

24 Effects of the correction SIMULATION DATA MC truth Uncorrected Corrected Truth - corrected RADIAL DISTANCE [55um] 24