GEMPIX detectors GEM with higly pixelated readout F

GEMPIX detectors : GEM with higly pixelated readout F. Murtas, G. Claps, E. Baracchini Laboratori Nazionali Frascati - INFN • Introduction • GEMPIX Detectors • GEMPIX Applications • Measurements: gain and drift velocity A. Balla, G. Claps, G. Corradi, G. Croci, E. Baracchini, D. Tagnani, D. Pacella F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 1

A triple GEM Chamber A Gas Electron Multiplier (F. Sauli, NIM A 386 531) is made by 50 m thick kapton foil, copper clad on each side and perforated by an high surface-density of bi-conical channels; 70 µm Several triple GEM chambers have been built in Frascati in the LHCb Muon Chamber framework* 140 µm GEM foil Working with different levels of gain it is possible to obtain high level of gamma- neutron discrimination F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 2

Main Characteristics The main characteristics are : - Extended dynamic range (from single particle up to 108 partcles cm-2 s-1) - Good time resolution (5 ns) - Good spatial resolution (200 m) - Radiation hardness (2 C/cm 2) Thanks to these characteristics a GEM detector can be used for: - plasma imaging for fusion reactors (tokamak) neutron and X rays, - diagnostics for beam particles (high energy physics, hadron therapy) - detectors for fast and thermal neutrons , - medical applications (diagnostics and therapy): - medical diagnostics medicale in gamma therapy; - medical diagnostics in hadro therapy; - steress diagnostics in industrial applications; - environment monitoring; - radioactive waste imaging; F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 3

GEMpix Assembling The detector has two main parts : - The quad medipix with a naked devices - The triple gem detector with HV filters and connector New HV GEM board 2. 8 cm Quad medipix board M. Campbell, J. Alzoy F. Murtas G. Claps, E. Baracchini 2. 8 cm Top view EDIT Frascati. October 22 h 2015 4

Head on detector Particles to be analysed 3 mm ionization gap Mylar window Triple GEM Gas flux AR CO 2 The detector is a quad naked medipixes (no silicon sensor): The active area is 9 cm 2 This type of device can be used for high flux of X rays Gain tuneable from 1 up to 104 Time resolution: 5 ns Energy sensitivity few ke. V F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 5

Side on detector Length analysed Kapton window Particles to be analysed Triple GEM Gas flux The detector is a quad naked medipix : The active area is 9 cm 2 The particle track is analysed with 512 pixel in 3 cm length The longest drift gap used up to now is 5 cm. F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 6

GEMPIX readout Wilkinson ADC TOA F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 7

GEMPIX detectors and HV Head-on Side-on (2 cm drift) TPC (5 cm drift) https: //web 2. infn. it/GEMINI/ HVGEM F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 8

GEMPIX applications Gempix Detector (10 cm 2 GEM detector read by 55 x 55 m pixels, 262 000 channels ) - radioactive CERN waste 55 Fe measurements (LEP, SPS, etc) - 3 D measurements of energy released in water phantom in hadrotherapy treatment facility (CNAO Pavia) - Gamma ray monitor for radiotherapy dose measurement (Polic. Tor Vergata Rome) - X ray monitor in Inertial Fusion test facility (Petal, France ) - X ray monitor in KSTAR Tokamak reactor (Korea) - Proton tomography prototypes (Nikef, Nederland) - Dark matter prototype for Directional dark mattersearches with carbon nanotubes - Dark matter prototype for NITEC: a Negative Ion Time Expansion Chamber for directional Dark Matter search Hadrotherapy Radiotherapy: GEMPIX vs radiochromic film 3 D reconstruction F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 9

GEMPIX for Fusion Laser Produced Plasmas (ABC, ENEA) Laser pulse duration = 3 ns Wavelenght = 1054 nm A maximum energy of 100 J per pulse Tokamak Plasmas (KSTAR, South Korea) F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 A frame every 700 ms 10

GEMpix detector and EBT gafcromic comparison through γ test: the bi-GEM configuration 6 MV γ < 1, 97. 57 % 8 x 8 mm 2 irradiating field Multileaf collimator 6 MV γ < 1, 90. 50 % 6 MV γ < 1, 87. 04 % F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 11

Bragg Peak finder at CNAO Phantom used at CNAO Stepper Motor Gempix Thin Window Several measurement of energy deposition along the beam (5 x 108 Carbon ions per 10 spills) F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 12

Energy deposition in hadrotherapy 3 D reconstruction F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 13

GEMPIX for radioctive waste Correlation between GEMPIX and Medipix Data acquired in one second X-ray candidates Bkg Very good pattern recognition and particle identification F. Murtas G. Claps, E. Baracchini GEMPIX 1 hour of data acquisition Medipix 10 hours of data acquisition External companies : days EDIT Frascati. October 22 h 2015 14

GEMPIX as Negative Ion TPC for directional Dark Matter searches --Larger allowed drift length thanks to negative ion suppressed diffusion J. Martoff et al. , NIM A 440 355 --3 D track reconstruction and head-tail discrimination capability thanks to time & charge GEMPIX measurements --Improved position and energy resolution thanks to possibility of single ionization cluster measurement Cluster structure clearly visible < 0. 5 mm diffusion achieved over 50 cm drift length w. r. t. 10 mm obtained with electrons (no magnetic field) F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 15

Measurements at EDIT 2015 Cosmic Rays in TOT mode cluster analysis Gain measurements with 55 Fe source Drift Velocity Measurements with the BTF eleectron Beam HV Control Online display FITPIX DAQ interfac HVGEM pixelman GEMPIX Online plots F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 16

The GEMPIX TPC 3 D reconstruction 70 counts 7 us. . . 5 cm F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 17

X Ray Source spectrum 4 points at 1300, 1260, 1220, 1180 V Geff = A eα(Vgem 1+Vgem 2+Vgem 3) A and α depend on the gas mixture. Mean charge 55 Fe HV Value F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 18

Online measurements Start with trigger end 10 us Beam F. Murtas G. Claps, E. Baracchini Single frame of 3 us EDIT Frascati. October 22 h 2015 19

Drift velocity measurement Y projection Drift Time X projection Z position F. Murtas G. Claps, E. Baracchini EDIT Frascati. October 22 h 2015 20