Calorimetric Low Temperature Detectors FAIR for Applications in NUSTAR Peter Egelhof GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany and University Mainz, Germany NUSTAR Annual Meeting 2016 GSI, Darmstadt February 29 - March 4, 2016
Calorimetric Low Temperature Detectors FAIR for Applications in NUSTAR I. Introduction II. Detection Principle and Basic Properties of Calorimetric Low Temperature Detectors (CLTD`s) III. CLTD`s for High Resolution Detection of Heavy Ions - Design and Performance IV. Applications of CLTS`s in Heavy Ion Physics - Status and Perspectives V. Conclusions
I. Introduction The success of experimental physics and the quality of the results generally depends on the quality of the available detection systems ! ⇒ idea: detection of radiation independent of ionisation processes � calorimetric detector ° thermometer particle or photon potential advantage: phonons • energy resolution interaction of radiation with matter: • energy linearity primary: ionization, ballistic phonons • detection threshold (conventional ionisation detectors) • radiation hardness secondary: thermalization: conversion of energy to heat ⇒ various applications in ⇒ detection of thermal phonons many fields of physics ⇒ calorimetric detectors
Applications of Low Temperature Detectors - an Overview Astrophysics: Atomic and Nuclear physics: • X-ray detection • dark matter ⇒ high energy resolution ⇒ low detection threshold • Ion detection • solar neutrinos ⇒ high energy resolution ⇒ low detection threshold ⇒ good energy linearity • cosmic x-rays Applied physics: ⇒ high energy resolution • x-ray material analysis Particle physics: ⇒ high energy resolution • ββ 0 ν -decay • life sciences ( MALDI ) ⇒ absorber = source ( 130 Te) ⇒ high energy resolution neutrino mass from β - endpoint determ. • for more detailed information see: ⇒ absorber = source ( 187 Re) • Cryogenic Particle Detection, Topics in Applied Physics 99 (2005) Proceedings 15 th Int. Workshop on • Low Temperature Detectors, JLTP (2014), 320 participants!
II. Detection Principle and Basic Properties of Calorimetric Low Temperature Detectors (CLTD`s) detection principle: thermal signal: absorber C incident particle thermometer R (T) ∆ T t 1 t 2 with energy E T ⇒ ⇒ T + ∆ ⇒ ⇒ ∆ ∆ ∆ T k thermal coupling time heat sink amplitude: ∆ T = E/C (C = c • m = heat capacity) rise time: τ 1 ≥ τ therm ( ≈ 1 – 10 µ sec) τ 2 = C/k ( ≈ 100 µ sec – 10 msec) fall time:
Optimization of the Sensitivity a) absorber: maximum sensitivity ∆ T = E/mc for – small absorber mass m – small specific heat c + β (T/ θ D ) 3 due to: c = α T ( θ D = Debye-temperature) electrons lattice ⇒ low operating temperature ⇒ „low-temperature detector“ ( α T dominating for T ≤ 10K ⇒ insulators ( α = 0) or superconductors) R b) thermometer: for thermistor (bolometer): ∆ T → ∆ R → ∆ U ⇒ maximum sensitivity for large dR/dT – semiconductor thermistor due to appropriate doping ⇒ exponential behavior of R(T) – superconducting phase transition thermometer T
Potential Advantage over Conventional Detectors • small energy gap ω ⇒ better statistics of the detected phonons semiconductor detector: ω ≈ 1 eV ω ≤ 10 -3 eV calorimetric detector: ω ∆ E N 1 phon calorimete r = electr . = ≤ ∆ ω E N 30 semicond . det . phon . electr . more complete energy detection ⇒ better linearity and resolution • energy deposited in phonons and ionisation contributes to the signal (for ionisation detectors: losses up to 60-80% due to: - recombination - direct phonon production) • small noise power at low temperatures • method independent on absorber material ⇒ optimize radiation hardness, absorption efficiency, etc.
Theoretical Limit for the Energy Resolution for ideal calorimetric detector: - thermodynamic fluctuations (quantum statistics) - Johnson noise - amplifier noise ⇒ 5 < ∆ >= ξ • < ξ < E k T c m 1 3 B noise thermodynamic fluctuations 1 MeV particle in a 1 mm 3 sapphire absorber example: ⇒ for low temperature: microscopic particle affects the properties of a macroscopic absorber
III. CLTD`s for High Resolution Detection of Heavy Ions - Design and Performance Detector Design and Perfomance: for an overview see: heavy ions P.E. and S. Kraft-Bermuth, slit aluminium- Top. Appl. Phys. 99 (2005) 469 thermometer low temperature absorber varnish copper coldplate heat sink U R L signal absorber: sapphire-crystal: V= 3 x 3 mm² x 430 µm aluminium-film (d = 10 nm), T C ≈ 1.5 ° K (in the range of a 4 He-cryostat) thermometer: (for impedance matching to the amplifier: ⇒ meander structure) readout: conventional pulse electronics +Flash-ADC`s +Digital Filtering
III. CLTD`s for High Resolution Detection of Heavy Ions - Design and Performance Detector Design and Perfomance: for an overview see: heavy ions P.E. and S. Kraft-Bermuth, slit aluminium- Top. Appl. Phys. 99 (2005) 469 thermometer low temperature 150 absorber varnish normal state 100 R [k Ω ] operation copper temperature coldplate heat 50 sink super- transition region: U R conducting dR/dT ≈ const L 0 1.60 1.62 1.64 1.66 T [K] signal absorber: sapphire-crystal: V= 3 x 3 mm² x 430 µm aluminium-film (d = 10 nm), T C ≈ 1.5 ° K (in the range of a 4 He-cryostat) thermometer: (for impedance matching to the amplifier: ⇒ meander structure) readout: conventional pulse electronics +Flash-ADC`s +Digital Filtering
CLTD`s for High Resolution Detection of Heavy Ions - Design and Performance 3 mm detector pixel: • absorber: heating absorber 3 x 3 x 0.43 mm 3 sapphire (Al 2 O 3 ) resistor • thermometer: Transition Edge Sensor (TES) 10 nm thick meander shaped Al-layer aluminum ⇒ photolithography (high purity!!) thermometer • heating resistor: cryostat Au/Cr strip • operation temperature: T c = 1.5 – 1.6 K CLTD-array detector array: • 8 pixels with individual temperature stabilization in operation • active area: 12 mm x 6 mm • windowless coupling of cryostat to beam line
New Large Solid Angle Detector Array number of pixels: 25 active area: 15 X 15 mm 2
CLTD`s for High Resolution Detection of Heavy Ions - Design and Performance detector performance: response to 32 S ions @ 100 MeV 6 -3 τ rise = 35 µs ∆ E/E = 1.6x10 80 rate capability: 4 ∆ E = 166 keV τ decay = 150 µs counts/bin 60 ≥ 200 sec -1 Volts 2 resolution: 40 0 ∆ E/E = 1.6 x 10 -3 20 -2 0 0 500 1000 1500 101.6 102.0 102.4 E [MeV] time [µs] systematical investigation of energy resolution: for 209 Bi, E = 11.6 MeV/u ⇒ ∆ E/E = 1.8 x 10 -3 with UNILAC-beam: for 238 U, E = 360 MeV/u ⇒ ∆ E/E = 1.1 x 10 -3 with ESR-beam: for 152 Sm, E = 3.6 MeV/u ⇒ ∆ E/E = 1.6 x 10 -3 with Tandem-beam: ⇒ for heavy ions: ≥ 20 x improvement over conventional Si detectors
Comparison of Detector Performance: CLTD – Conventional Si Detector 1600 500 conventional energy resolution: 1400 calorimetric Si - detector 400 1200 detector example: counts/bin 1000 300 counts/bin ∆ E = 2808 keV ∆ E = 91 keV 800 238 U @ 20.7 MeV ) 200 600 400 100 200 S. Kraft-Bermuth et al. 0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 28.0 30.0 0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 28.0 30.0 energy [MeV] Rev. Sci. Instr. 80 (2009) 103304 energy [MeV] 2400 7000 � 4 He 2200 � 4 He energy linearity: 6000 peak position [channel] peak position [channel] 2000 � 13 C � 13 C 5000 1800 example: � 197 Au � 197 Au 4000 1600 � 238 U � 238 U 3000 1400 13 C, 197 Au, 238 U 13 C, 197 Au, 238 U 2000 1200 1000 1000 0 800 0 10 20 30 40 50 60 70 0 5 10 15 20 25 E [MeV] E [MeV] for conventional ionization detector: high ionization density leads to charge recombination (E- and Z- dependent) ⇒ pronounced pulse height defects ⇒ nonlinear energy response ⇒ fluctuation of energy loss processes ⇒ limited energy resolution
IV. Applications of CLTD`s in Heavy Ion Physics (NUSTAR) – Status and Perspectives • High Resolution Nuclear Spectroscopy • Investigation of Stopping Powers of Heavy Ions in Matter • In-Flight Mass Identification of Heavy Ions • Investigation of Z-Distribution Yields of Fission Fragments
Applications: a) High Resolution Nuclear Spectroscopy nuclear spectroscopy: • elastic and inelastic scattering ⇒ separation of inelastic channels ⇒ identification of reaction channels • nuclear reactions Example: Nat Pb ( 20 Ne, 20 Ne’), E = 100 MeV/u (CLTD adjusted to range of Ne ions) investigation of giant resonances elastic scattering (collective excitation of nuclear matter) 1000 events / channel J. Meier et al. giant resonance expected 100 Nucl. Phys. A 626 (1997) 451c 10 1900 1920 1940 1960 potential applications: energy [MeV] ⇒ investigation of multi phonon giant resonances ⇒ reactions at low energies (LEB at FAIR)
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