News on PbWO 4 Crystals

Transcription

1 June 16, 2015 Jlab - R. W. Novotny News on PbWO 4 Crystals R. W. Novotny II.Physics Institute, University Giessen, Germany and for the PANDA collaboration The PANDA requirements Some comments on radiation hardness Available manufacturer SICCAS CRYTUR Status

2 the PANDA detector at FAIR photon detection with high resolution over a large dynamic range: barrel 10MeV < E g < 15GeV high count-rate capability ( ~ Annihilations/s) nearly 4p coverage sufficient radiation hardness endcaps timing information for trigger-less DAQ concept shashlyk-type Sampling Calorimeter Target Spectrometer PWO-II 200mm (23X o ) ~4.000 crystals 4p detector for spectroscopy and reaction dynamics with antiprotons

3 the Target Spectrometer: based on high-quality PWO-II

4

5 T, % T, % Change of the transmission under hadron irradiation wavelength, nm wavelength, nm Change of the longitudinal transmission of 22 cm long PWO crystals after irradiation with ϒ-quanta (60Co, 1000Gy) and 24GeV protons with fluence 3, p/cm 2.

6 PWO: Short term intense irradiation by g-quanta 60 Co (1.2MeV, 1 MGy) Radiation induced absorption spectrum and its approximation with set of Gaussians

7 dk, m-1 PWO: intense irradiation with 24GeV protons (3.6x10 13 (p/cm 2 ) Spectrum cutoff shift Sum of bands 30.0 Experimental curve x1=3.56 ev (348 nm) x2=3.18 ev (390 nm) x3=2.75 ev x4=2.48 ev (451 nm) (500nm) x5=2.26 ev (548 nm) x6=1.79 ev (692nm) Energy, ev Radiation induced absorption spectrum and its approximation with set of Gaussians

8 consequences of cooling rel. light 25 o C / % fast decay kinetics even at T=-25 o C: LY(100ns)/LY(1µs) > 0.9 constant temperature gradient: LY(-25 o C)/LY(+18 o C) ~ 3.9 no statistical recovery of radiation damage at T=-25 o C asymptotic light loss correlated with Dk (@RT) T= -25 C RT / m -1

9 radiation hardness: limitations at T=-25 o C PMT output / a.u. PMT output / a.u 2 rad/h 20 rad/h +20 C -25 C recovery pilot-experiments at Protvino o C / GI PWO-II - 28 recovery at 25 o C PWO-II - 30 time time / h/ h SCINT07

10 Optical transmission: stimulated recovery in PWO WO 3 + O is an oxygen vacancy and oxygen ion in a close intersite position (FTD) Electronic transitions in PWO containing FTD and dedicated absorption bands

11 stimulated recovery of radiation damage Spontaneous LED_1550nm LED_1300nm k (420 nm) / m LED_1060nm LED_940nm LED_464nm illumination time / min applied integral dose of 60 Co: D = 30Gy V. Dormenev et al., NIM A623 (2010) patented

12 implications for EMC operation

13 overall quality of the available BTCP crystals

14 remaining PWO manufacturer SICCAS Shanghai, China R&D continued in parallel Bridgeman technology (not comparable to BTCP) fully acceptable crystals delivered in the past presently search for appropriate raw material and optimization of technology CRYTUR Turnov, Czech Republic R&D phase just started (June 2014) Czochralsky technology (identical to BTCP) know-how and raw material still available

15 how to produce crystals Czochralsky-method Bridgeman-technology

16 former SICCAS

17 recent delivery from SICCAS ( )

18 recent delivery from SICCAS (1)

19 recent delivery from SICCAS (1)

20 recent delivery from SICCAS (1)

21 recent delivery from SICCAS May 2015

22 recent delivery from SICCAS May 2015 SICCAS 1475

23 additional new PWO manufacturer CRYTUR Turnov, Czech Republic R&D phase just started (June 2014) Czochralsky technology (identical to BTCP) know-how and raw material still available

24 start CRYTUR (1) first experiences under different conditions: supported by: RINP Minsk: M. Korjik small test samples NEOCHEM, Moscow: Dosovitskyi first and second full size ingot (~ 23cm long)

25 start CRYTUR (2) Longitudinal induced absorption coefficient of CRYTUR PWO 1,4 1,2 test crystal: 20 x 20 x 200 mm 3 dk, m -1 1,0 dk 5 Gy dk 10 Gy 0,8 dk 20 Gy dk 30 Gy 0,6 dk 50 Gy dk 70 Gy dk 100 Gy 0,4 dk 150 Gy dk 200 Gy 0,2 0, wavelength, nm longitudinal inhomogeneity scattering centers sufficient light yield radiation hard dk, m -1 1,4 1,2 1,0 0,8 0,6 0,4 0,2 Radiation induced coefficient vs deposited dose dk360n dk420n dk620n 0, Dose, Gy

26 Transmittanse, % Transmittance at 360 nm, % test crystal: 20 x 20 x 200 mm 3 80 Lateral Transmittance of CRYTUR PWO crystal, Lateral Side 1 70 Transversal transmittance at 360 nm vs position for different sides Before irr. 1 cm Before irr. 3 cm 50 Before irr. 5 cm Before irr. 7 cm 40 Before irr. 9 cm Before irr. 11 cm 30 Before irr. 13 cm Before irr. 15 cm 20 Before irr. 17 cm Before irr. 19 cm 10 Longitudina transmittance of CRYTUR PWO Longitudinal transmittance of BTCP PWO wavelength, nm T360nm, % (Side1) T360nm, % (Side2) T360nm, % (Side3) T360nm, % (Side4) Position, cm dk, m -1 1,5 1,4 1,3 1,2 1,1 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0 Lateral transmittance of CRYTUR PWO crystal, Lateral Side 2 Lateral position = 1 cm Lateral position = 3 cm Lateral position = 5 cm Lateral position = 7 cm Lateral position = 9 cm Lateral position = 11 cm Lateral position = 13 cm Lateral position = 15 cm Lateral position = 17 cm Lateral position = 19 cm Longitudinal Longitudinal (30 Gy dose) wavelength, nm dk, m -1 1,5 1,4 1,3 1,2 1,1 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0 Radiation induced coefficient vs position, Lateral Side 2 Integral dose= 200 Gy Position, cm dk360nm dk420nm dk620nm

27 Transmittanse, % Transmittanse, % test crystal: 20 x 20 x 100 mm 3 80 Transversal transmittance of CRYTUR (10 cm) PWO crystal Before irr. 1 cm 50 Before irr. 3 cm Before irr. 5 cm Before irr. 7 cm Before irr. 9 cm 10 Longitudina transmittance of CRYTUR PWO Longitudinal transmittance of BTCP PWO wavelength, nm 60 Transversal transmittance of CRYTUR (10 cm) PWO crystal After irr. 1 cm After irr. 3 cm After irr. 5 cm After irr. 7 cm After irr. 9 cm wavelength, nm

28 Transmittance, % Transversal radiation induced coefficient of test crystal: 20 x 20 x 100 mm 3 2,0 1,5 CRYTUR (10 cm) P Integral dose= 200 Gy 1,0 dk, m -1 0,5 0,0-0,5 dk 1 cm dk 3 cm -1,0 dk 5 cm dk 7 cm -1,5 dk 9 cm Longitudinal dose= 30 Gy 80-2,0 Longitudinal dose= 200 Gy wavelength, nm Transversal transmittance vs position bi T360nm, % ai T360nm, % bi T420nm, % ai T420nm, % bi T620nm, % ai T620nm, % Position, cm

29 dk, m-1 Transmittanse, % Longitudinal Transmittance of CRYTUR (10 cm) PWO Before irr. 50 After irr. 5 Gy After irr. 10 Gy 40 After irr. 20 Gy After irr. 30 Gy 30 After irr. 50 Gy After irr. 70 Gy 20 After irr. 100 Gy After irr. 150 Gy 10 After irr. 200 Gy BTCP 1913 ECR wavelength, nm 2,0 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 test crystal: 20 x 20 x 100 mm 3 Longitudinal induced absorption coefficient of CRYTUR (10 cm) PWO dk 5 Gy dk 10 Gy dk 20 Gy dk 30 Gy dk 50 Gy dk 70 Gy dk 100 Gy dk 150 Gy dk 200 Gy 0, wavelength, nm

30 LY, phe/mev test crystal: 20 x 20 x 100 mm 3 21,0 20,5 20,0 Light Yield of CRYTUR(10 cm) PWO crystal vs position "Bottom" side attached to PMT "Top" side attached to PMT 19,5 19,0 18,5 18, Distance to PMT, cm

31 CRYTUR status July 15: installation of 4 ovens polishing and cutting order of R&D crystals Giessen Uppsala next of July production start in August

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33 the quality requirements

34 some general remarks on PWO index of refraction increased light yield due to doping

35 production at BTCP

36 quality control and performance

37 the optical transmission

38 tungstate crystal grown from stoechiometric raw material, which was measured at 20 and at radiation 1x10 5 min hardness after irradiation. Inset shows a normalized change of the induced absorption coefficient at 380, 440, and 600 nm versus time FTD 2- O - V Pb O - Dk, rel.un nm 440 nm 600 nm D k, m E+00 1.E+02 1.E+04 1.E+06 Time, min min after irradiation 10 5 min after irradiation l, nm Typical Fig.2.2.a induced Typical absorption spectra of slowly spectra recovering of radiation PWO induced undoped absorption and of uncompensated PWO. crystal grown in early days

39 optical longitudinal transmission light 18 o C longitudinal homogeneity

40 radiation hardness tested using g-rays: ~ 1.2 MeV 60 Co integral dose: 30Gy Dk ln T T bef after 1 d acceptance limit: Dk < 1.1 m -1

41 light yield measurement temperature dependence of luminescence

42 observation of severe radiation damage due to hadrons G. Dissertori et al., NIM A684 (2012)57 CMS 24 GeV/c protons fluence: (1.32 ± 0.11)10 13 cm -2 thermal treatment up to T=350 o C measurements and GI started several months after irradiation: stimulated recovery + heating

43 similar observation for 150MeV protons fluence: 1.8 x p/cm 2 similar shift like at 24GeV/c strong radiation damage due to protons at high fluence severe damage due to highly ionizing secondaries clusters of color centers due to ion displacements damage due to g-rays: stimulated recovery proton damage: annealing by heating

44 prototype performance extension response to to energies high energy < 50MeV MaxLab energy resolution tagged photon MAMI, Mainz E g = 26 MeV e - 64 MeV < E g 1.5 GeV g s E g =43.3MeV readout with incident energy / GeV photomultiplier optimized light output: PWO-II cooling: operation at T=-25 o C readout with photomultiplier

45 prototype performance PROTO 60 photon beam crystals in PANDA geometry readout with single LAAPD only quad preamplifier LED based monitoring system temperature stabilization <0.05 o C

46 prototype performance PROTO 60 counts / E / % 158 MeV E 1.78% E / GeV 0.69% 858 MeV 1.44 GeV deposited energy / MeV incident photon energy / MeV digitization: shaping /peak-sensing ADC

47 readout via SADC: further improvement energy-resolution ( 3x3 matrix ) 1 ns time resolution

48 prototype performance PROTO GeV positrons /E= 1.4% (x,y)~1mm

49 alternatives?