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Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Scintillator-based online detectors for laser-

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Presentation on theme: "Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Scintillator-based online detectors for laser-"— Presentation transcript:

1 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Scintillator-based online detectors for laser- accelerated protons – Concepts and realizations at the DRACO lab J. Metzkes, K. Zeil, S.D. Kraft, N. Stiller, U. Schramm, L. Karsch, C. Richter, J. Pawelke, M. Sobiella Instrumentation for Diagnostics and Control of Laser-Accelerated Proton (Ion) Beams II June 7 – 8, 2012

2 Seite 2 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes The DRACO laser facility time [fs] 30 fs Ti:Sapphire CPA laser rep rate: 10 Hz 2-3 J (on target) I ~10 21 W/cm 2 ns-ASE contrast *Dresden laser acceleration source

3 Seite 3 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Proton acceleration at DRACO wheel 2D offline target changer target manipulation Thomson parabola small solid angle online online laser parameter control

4 Seite 4 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Proton acceleration at DRACO wheel 2D offline target changer target manipulation Thomson parabola small solid angle online online laser parameter control Status stable high repetition rate laser system reliable proton source high degree of remote control under vacuum online optimization and monitoring of acceleration performance application experiments online spectrometers for protons & ions (1D or 2D) NEED

5 Seite 5 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Why plastic scintillators? Mainly practical reasons: easy to handle available in nearly any size and thickness no support necessary immediate light emission after excitation online information variable emission wavelength in the visible range signal readout with CCD cameras less EMP issues fast decay rates possible TOF applications linear response to particle flux light emission saturates with dE/dx calibration light emission degrades with total dose exposition

6 Seite 6 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector setup 1D angularly resolved online spectrometer for protons scintillator stack: 10 layers of BC 418 (Saint-Gobain crystals), maximum 391 nm resolution of 10 proton energy ranges light guide principle slim scintillator unit (15 mm x 76 mm) fan-like setup for good spatial resolution detection area: 10 mm x 50 mm detection angle as for RCF (~ 26° half angle ) compact detector: scintillator and camera unit only 300 mm x 80 mm radiation shielding with Pb

7 Seite 7 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector setup camera: 16 bit camera high dynamic range 1600 x 1200 px chip size, 4.4 µm pixel size camera unit directly coupled to the scintillator: light tight connection stray light suppression high light yield good spatial resolution 7px per layer thickness

8 Seite 8 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Imaging properties edges roughened to avoid reflection imaging edge polished spatial resolution surfaces polished for efficient reflection 182 mm 8.6 mm

9 Seite 9 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector setup & proof of principle proton distribution reconstructed from RCF p+ energy Measured proton distribution CCD camera image

10 Seite 10 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector setup & proof of principle p+ energy Measured proton distribution CCD camera image sufficient signal-to-noise ratio (>2) for signal detection shielding against electron and x- ray background maximum proton energy and yield online accessible for the full divergence angle of the proton beam online detection of beam inhomogeneities improves online beam optimization

11 Seite 11 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector Tandetron 6 MV tandetron at the HZDR Ion Beam Center 12 MeV p+ beam FC – 25.4 mm diam. detection surface current ~ 100pA detector reference RCF – beam homogeneity beam defining aperture – 10 mm diam. reference RCF – beam position

12 Seite 12 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Sensitivity calibration

13 Seite 13 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Sensitivity calibration dE/dx saturation of scintillator light output light transport within the scintillator case correction possible condition of polished scintillator edge

14 Seite 14 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Lateral homogeneity lateral position decrease due to imaging properties overall lateral homogeneity: ~ 80% inhomogeneity due to scintillator conditions stable measured curves give correction factors

15 Seite 15 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Imaging properties testing spatial resolutionimaging properties

16 Seite 16 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Imaging properties testing spatial resolutionimaging properties

17 Seite 17 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector application Idocisaperture beam filter aperturetargetlaser online detector proton beam Phys. Med. Biol. 56 (2011) 1529–1543 non-invasive online access to spectral distribution and yield of accelerated protons

18 Seite 18 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes Detector application optimal focus25 µm out of focus dispersion energy online optimization & monitoring of experimental performance via maximum proton energy & yield shot-to-shot monitoring via yield (higher sensitivity) online spectral monitoring dosimetry

19 Seite 19 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes 2D online detector development profile A-A` profile B-B` profile C-C` 2,5 0,40,71,0 1,92,12,5 1,21,4 1,6 Idea: mimic an RCF stack 2D spectrum ONLINE ~ 50 4,5 AA` BB` CC` Schnitt A-A` Schnitt B-B` Schnitt C-C` 2,5 0,40,71,0 1,92,12,5 1,21,4 1,6 CCD camera scintillator

20 Seite 20 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes 2D online detector development ~ 50 4,5 AA` BB` CC` camera unit absorber matrix & scintillator (BC 416, thickness 260 µm) Detector setup

21 Seite 21 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes 2D detector testing test with 12 MeV p+ basic pixel (9 energies): 4.5 x 4.5 mm 121 pixels on a 50 x 50 mm plate diam 1.5 mm dist 2.0 mm diam 1.5 mm dist 2.25 mm diam 1.5 mm dist 2.50 mm diam 1.5 mm dist 2.75 mm diam 1.0 mm dist 1.50 mm Test matrix optimized for tandetron experiment (12 MeV protons)

22 Seite 22 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes 2D detector testing basic pixel (9 energies): 4.5 x 4.5 mm 121 pixels on a 50 x 50 mm plate Progress final design for basic pixel sensitivity tandetron test of p+ scattering in angled holes To do test of a final DRACO performance with background radiation

23 Seite 23 Mitglied der Helmholtz-Gemeinschaft Josefine Metzkes (multiple filamentation of a freely propagating 100 TW beam in air) … thanks for your attention


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