Antoine Drouart DSM/DAPNIA/SPhN. Köln, 5 th of December,

Transcription

1 Köln, 5 th of December,

2 Basic CATS/BTD mechanics Köln, 5 th of December,

3 Beam Tracking Today -Detector able to cope with a few 10 5 pps -Spatial resolution (FWHM) : 0.7mm -Time resolution (FWHM) : 1.5ns (light ions) to 400ps (heavy ions >O) -Total thickness in the beam : 4.8μm Mylar foils + 2cm gas (4torr) ~ 700μg/cm 2 SPIRAL 2 Beams - Low energy, high masses MeV/u Straggling = 1.82 mrad (FWHM) MeV/u Straggling = 3.64 mrad (FWHM) BTD are too thick! Köln, 5 th of December,

4 Secondary Emission detectors Emissive foil detectors ~ 50µg/cm2 of carbon possible on a few cm 2 Secondary electrons Emissive foil (Mylar+Al, Carbon) B Ion beam E Secondary electron detector Secondary electron detector -Gas detector - Micro-channel plates - others : Micromégas, diamonds? MeV/u δθ = 0.47 mrad (FWHM) ( ~BTD with 8He@15MeV/u) MeV/u δθ = 0.94 mrad (FWHM) Köln, 5 th of December,

5 Secondary Electron Detector for VAMOS Spectrometer Secondary Electron Detector Emissive foil Metal testing Mask Incoming ions Magnetic coils - Siez : 10 x 40 cm 2 (focal plane detectors) - Counting rate = 10 3 pps (limited by electronics dead time) - Theoretical limit ~10 7 pps - Spatial resolution : 1-2 mm - Time resolution : 1.5ns (light ions) to 300ps (heavy ions Z>40) - Total thickness in the beam : 0.6μm Mylar foil = 75μg/cm 2 Köln, 5 th of December,

6 Estimated Performances Optimum for low energy, heavy ions (Z>10) Ions Measurements with the Se-D detector on VAMOS (low pressure proportional counter, 10*40cm 2 ) Energy (MeV/A) de/dx (MeV/mm) Efficiency Time resolution (FWHM ps) Heavy Fission frag. Average Z~ % 250 Light fission frag. Average Z~ % Ge % Mg % C % 1000 Alpha %(70%*) 1200* Mini Se - D (7x7cm 2 ) under (re)construction( Köln, 5 th of December,

7 Improvement for SPIRAL2 Position resolution < 1mm Active area > 5x5cm 2 Increase the counting rate up to 10 7 pps Paths of R&D for the secondary electron detector Large size micro-channel plates Mini-Se - D? Micromegas? Diamond detectors Collaboration with Huelva and Sevilla Universities + New Fast electronics Synergy with the Low energy Köln, 5 th of December,

8 B-TrackS Beam TRACKing at Saclay Köln, 5 th of December,

9 CEA Saclay test Bench Vacuum Chamber for test with 241 Am or 252 Cf sources Köln, 5 th of December,

10 CEA Saclay test Bench 2 turbo pumps (oversized ) Main pump Köln, 5 th of December,

11 CEA Saclay test Bench Coincidence Silicon detector Collimated Source Detector Other detector For Time of flight Köln, 5 th of December,

12 CEA Saclay test Bench Gas pumping machine ( 2<P<100mbar) for isobutane or others gases! Absolute Calibration of the pressure is difficult! Köln, 5 th of December,

13 CEA Saclay test Bench Electronics -Local electronics for charge amplification - NIM electronics - fast amplifiers (time) - coincidence - Constant fraction discriminators - VME/CAMAC Coding -QDC - Sampling Matacq Card (time) - LabView acquisition system on PC Köln, 5 th of December,

14 CEA Saclay test Bench Staff 1 Physicist (20%) 1 engineer (50%) 1 mechanics technician (20%) 1 electronics technician (20%) + technician from Sevilla Project for 2008 Study alternative types of Secondary e - Detectors Build a prototype detector for low energy Beams - Existing electronics - Estimate its performances : simulations & source tests (first half of 2008) beam tests (Sevilla) 1 st Step : have a first operational mini-se - D end Köln, 5 th of December,

15 Köln, 5 th of December,

16 Detector principle Julien Pancin X PPAC zone MWPC zone Thin 1.5 µm mylar foil 32 cathode strips at V=0 V, 2.54 mm pitch, Al. evap. on 0.9 µm mylar foil Low pressure gas ic4h10 at 6 Torr 3.2 mm E [V/cm] X E Field in the detector Y 71 Anode wires 10 µm diameter at V=+ 600V (Not on scale) 7 cm Constant field zone: PPAC, position Particle signal on the strips High gradient field zone: MWPC, time signal on the wires X [mm] Köln, 5 th of December,

17 Detector description Julien Pancin Köln, 5 th of December,

18 Time resolution calculated using 3 detectors Time and spatial resolution Julien Pancin Spatial resolution using a 500 μm hole σ t = 250 ps +/- 20 ps X [mm] hbar Entries 591 Mean RMS c / ndf / 18 p p p p σ x,y = 380 μm +/- 40 μm (To re-do with a better set-up) Köln, 5 th of December,

19 Electronic improvments Julien Pancin Détecteur Simplified connectics Amplis and electronic more integrated Amplifier modules close to the detector Numerical delay for each strip Only the strips really fired are registered No dead time (apart from delay) : count rate = 1 MHz/strip Baie Electronique The count rate limit is not any more Baie on retard the electronics Köln, 5 th of December,

20 BTD final characteristics (vs CATS) Count rate capability ~ 10 5 pps/cm 2 Low dead time 1 μs / strip Spatial Resolution : σ X, σ Y ~ 400 μm Julien Pancin CATS μs 500 μm Time resolution < 0.5 ns Efficiency > 90 % 8 He@15 MeV/n 1,7 ns 83 % To be tested now in beam Köln, 5 th of December,

21 Secondary Electrons Detection Julien Pancin Köln, 5 th of December,

22 SED Secondary Electron Detector Julien Pancin Emissive foil Metal testing Mask Incoming ions Magnetic coils - Counting rate = 10 3 pps (limited by electronics dead time) - Theoretical limit ~10 7 pps - Spatial resolution : 1-2 mm - Time resolution : 1.5ns (light ions) to 300ps (heavy ions Z>40) - Total thickness in the beam : 0.6μm Mylar foil = 75μg/cm 2 Köln, 5 th of December,

23 Perspectives and new R&D in 2007 Julien Pancin End of BTD project in middle 2007 : Supply of 3 BTD to GANIL Installation of 2 BTD in march 2007 at GANIL, first real in-beam test with electronics New R&D project on beam tracking to fit with SPIRAL2: - SED with Micromegas Gain Gain comparison in BTD ic 4 H 10 6 Torr First promising tests : mumegas - no sparking - signal Amplification at low pressure X [cm] Köln, 5 th of December,