MICRO PIXEL AVALANCHE PHOTODIODE AS ALTERNATIVE TO VACUUM PHOTOMULTIPLIER TUBES

Transcription

1 MICRO PIXEL AVALANCHE PHOTODIODE AS ALTERNATIVE TO VACUUM PHOTOMULTIPLIER TUBES G.S. Ahmadov, Z.Y. Sadygov, F.I. Ahmadov National Nuclear Research Centre, Baku, Azerbaijan G.S. Ahmadov, Z.Y. Sadygov, Yu.N. Kopatch Joint Institute for Nuclear Research (JINR),Dubna 25-th International Seminar on Interaction of Neutrons with Nuclei: «Fundamental Interactions & Neutrons, Nuclear Structure, Ultracold Neutrons, Related Topics» Dubna, Russia, May 23 27, 2017

2 Talk Outline

3 Solid State Motivation...is to provide a solid-state alternative to the vacuum tube based photomultiplier tube (PMT)... Plasma tv (Bitzer/Gene Slottow) Vacuum Tube Silicon Transistor (Texas Inst.) 1875 LightBulb (Edison) CRT (Ferdinand Braun) LED (Holonyak) 1950 SiMP Photomultiplier Tube (RCA) Vacuum Tube Diode (Fleming) ENIAC (17,468 Tubes)

4 Photodetectors Vacuum photomutliplier tubes PMT was invented more than 80 years ago and was first device to detect light at the single-photon level. They are widely used in many applications up to now. Advantages: High gain factor ( ) Low Noise Large areas (up to several dm2) Disadvantages: Large size Sensitivity to magnetic fields High supply voltage The relatively high cost Quantum efficiency (up to 25%) PiN diodes PiN diodes are also used in various experiments. Such diodes have a very simple structure, since the i-region (semiconductor) lies between the regions of n and p conductivity. They do not have internal amplification. Advantages: Good linearity (dynamic region) Quantum efficiency reaches 90% Disadvantages: High operating voltage Sensitivity to other kinds of radiation (Nuclear counter effect) Requires charge sensitive amplifiers

5 Avalanche photodiodes M Ordinary Linear mode Geiger mode photodiodes 0 Response to a photon Breakdown voltage I(t) 1 M<103 M>103

6 MAPD vendors MEPhI/Pulsar (Moscow) - Dolgoshein CPTA (Moscow) - Golovin Mikron (Moscow) - Sadygov now Zecotek (Singapore) - Amplification Technologies (Orlando) Hamamatsu Photonics (Hamamatsu, Japan) SensL(Cork, Ireland) AdvanSiD (former FBK-irst Trento, Italy) STMicroelectronics (Italy) KETEK (Munich) RMD (Boston, USA) ExcelitasTechnologies (former PerkinElmer) MPI Semiconductor Laboratory (Munich) Novel Device Laboratory (Beijing, China) Philips (Netherlands) Every producer uses its own name for this type of device: MRS APD, G-APD, MAPD, SiPM, SSPM, MPPC, SPM, DAPD, PPD, SiMPl, dsipm Prices: about 15 / mm2 which is 10 times lower than in 2008

7 Two main designs of MAPD The Hamamatsu and SENSL technology does not allow producing high density cells (>5000 cells / mm2) and high PDE (>15%). However, their technology makes it possible to obtain very fast pixel recovery times (<6 ns). GAPD can be triggered several times due to the fast recovery of pixels, which should lead to an effective increase in the dynamic range of the GAPD. Equivalent circuit of a pixel of the GAPD Zecotek technology allows the production of high-density pixels (> pixels/mm2) and high PDE (> 25%). However, the Zecotek MAPD has a slow pixel recovery time (95% is restored in < 1 µs). In this technology, the function of a quenching individual resistor is performed by artificial potential wells. Equivalent circuit of a pixel of the GAPD

8 MAPD from Zecotek Photonics Inc. MAPD 3A 3B 3N 3N1P K0 Pixel densitypix/mm Size,mm 2 3x3 3x3 3x3 3x3 3.7x3.7 PDE, % ( ) ~13 ~13 ~30 ~30 ~40 Gain Voltage ~66 ~70 ~90 ~90 ~90

9 Micropixel avalanche photodiode Silicon photomultipliers are nowadays considered a promising alternative to conventional vacuum tube photomultipliers. MAPD is one successful type of the silicon photomultipliers. Micro-pixel avalanche photodiode manufactured by Zecotek Photonics Inc. Design of MAPD PDE (~40%) High gain (~106) Low operation voltage (~90 V) High pixel density (1*104-4*104 pix./mm2) Insensitive to magnetic field very compact very robust 1-Si substrate of n-type; 2 - epitaxial layer of n-type; 3 epitaxial layer of p-type; 4 - thin layer of n + -type; 5 - n+ -type regions (pixels); 6 - p+ -type layer; 7 - metal contact; 8 - guard ring n + - type; 9-n+ -type layer. 9

10 Operational principle The basic operation can be explained in three modes as charge, discharge and quenching. To simplify the explanation, we assume the MAPD as capacitance like element. This capacitance is charged at Vop (charge) and stands till incidence of photon occurs. The photon incidence occur the avalanche process in MAPD, and current will begin to flow (discharge). The existence of quenching resistor (artificial potential wells) limit the recharge of MAPD, so decrease of Q, also decrease Vop Vbr and avalanche process will stop (quenching) but recharge through the quenching resistor will continue after the quenching process (recharge).

11 Gain The gain can be calculated from the overvoltage ΔV, the microcell capacitance C, and the electron charge, e. G=C ΔV/e 11

12 Recovery time The recovery time of pixels is depend on the density of impurities in pixels (n + -regions) and on the depth of the potential well (capacity). The potential well serves as a quenching individual resistor in MAPD. APD (1) and MAPD-3B (2) MAPD-3A (1) and MAPD-3N (2) MAPD-3A (1) and MAPD-3N (2)

13 MAPD Timing Response Measurement of MAPD with LFS-8 crystal and 22Na source MAPD contains 15k/mm2 Single Photon Counting Detectors 13

14 Photon detection efficiency (PDE) The photon detection efficiency (PDE) is a measure of the sensitivity of an SiPM and is a function of wavelength of the incident light, the applied overvoltage and microcell fill factor. The PDE differs slightly from the quantum efficiency (QE) that is quoted for a PMT or APD, due to the microcell structure of the sensor. The PDE is the statistical probability that an incident photon interacts with a microcell to produce an avalanche, and is defined as: PDE(λ,V) =η(λ) ε(v) F η(λ)-the quantum efficiency of silicon ε(v)-the avalanche initiation probability F - the fill factor of the device.

15 Linearity and dynamic range of MAPD Zecotek technology allows to produce MAPD with high pixel density(>15000 cells / mm 2). This is very important, since it allows to cover a wide range of photon energies (even more than 30 GeV), if assuming that a 1 GeV photon produces up to two thousand photoelectrons. The gain is Sensitive area mm2 Number of pixels - 1,5 104 / mm2 Operating voltage - 90 V The efficiency of photon registration is 25% The number of pixels ensures the linearity of the MAPD A large pixel density or fast recovery time is needed for a large dynamic range Коэффициент усиления - 1, Чувствительная область mm2 Число пикселей - 1,5 104/mm2 Рабочее напряжение - 90 В Эффективность регистрации фотонов - 25% Светодиод с длиной волны 450 нм (1кГц, 10 нс)

16 Temperature dependence

17 Temperature dependence Sequence of 500 pulse shapes from a Zecotek SiPM of type MAPD-3N at a bias voltage of V, operated at T=4 K. The average light intensity was of the order of one photon. Pulse shape from a Hamamatsu SiPM of type S P operated at 77 K. The long falltime of the signal over microseconds shows the failing quenching process. M. Biroth et al. Nuclear Instruments and Methods in Physics Research Section A, Volume 787, 2015, p

18 Radiation hardness of MAPD The diodes were irradiated with protons with energy 150 MeV in Phasotron accelerator (DLNP, JINR). 1- before 2-1*1010proton/cm2 3-5*1010proton/cm2 4-1*1011proton/cm2 MPSF-3N1P

19 Registration of electrons The signal and the pulse height spectrum was obtained using a GUN-UV lamp (6-16 kev).

20 Registration of alpha particles Pulse height spectrum of alpha particles from radioactive source Am-241 (5.5 MeV)

21 Scintillation detectors based on MAPD Material NaI(Tl) LFS-3 LFS-8 LYSO LiI(Eu) BGO Density(g/cm3) Light output (%) Decay time, (ns) < Peak emis, (nm)

22 Gamma ray scintillation detectors based on MAPD and NaI(Tl) scintillator Cs-137 gamma source (662 kev)

23 Gamma ray detector based on MAPD matrix (2*2) and LYSO scintillator The size of the scintillator was 6*6*2 mm3, and the matrix - 7.5*7.5 mm2.

24 Gamma ray scintillation detectors based on MAPD and LFS scintillator Gamma ray energy spectra were obtained using LFS-8 scintillator (3*3*0.5 mm) coupled to MAPD. The MAPD gives good linearity up to 1 MeV (gamma).

25 Neutron detectors based on MAPD+ LiI(Eu) and plastic scintillator LiI(Eu) scintillator gives light yield of photons/mev deposited energy of gamma and photons/neutron for neutron It is characterized by its decay time of 1400 ns. The maximum wavelength of light emission is 420 nm. Plastic scintillator gives light yield of photons/mev deposited energy, and characterized by its decay time of 3.7 ns. The maximum wavelength of light emission is 420 nm. Neutron and gamma spectra from Ti-44 gamma and PuBe neutron source Neutron and gamma spectra from Ti-44 gamma and PuBe neutron source

26 Thank you very much for your attention!