CAEN. Electronic Instrumentation. CAEN Silicon Photomultiplier Kit

Transcription

1 CAEN Tools for Discovery Electronic Instrumentation CAEN Silicon Photomultiplier Kit CAEN realized a modular development kit dedicated to Silicon Photomultipliers, representing the state-of-the art in low light filed detection with photon number resolving capabilities. The kit can be configured in three basic configurations for three different applications: One set up is ideal for making easy SiPM tests and characterization, using the Ultra-Fast Led Driver especially developed for this Kit. The mini-spectrometer configuration allows the take of gamma-rays spectra through the use of 3 different scintillating crystals and a dedicated 3 X 3 SiPM, all mounted in an easy handling set-up. Cosmic rays and beta particles detection are also made possible through a polystirene plastic scintillating tile, using the discrimination and the coincidence performance of the CAEN digitizer DT5720A.

2 Application Basic set-up for sensor testing & characterization The development kit can be configured for making easy SiPM tests and characterization. Most of the basic detector figures (e.g. gain, photon number resolving power and Dark Count Rate at different photo-electron threshold) can be measured with a set-up including the Ultra-fast LED driver SP5601, the General Purpose Amplifier and Power Supply Unit (SP5600) housing the SiPM under test and the CAEN Desktop Waveform digitizer mod. DT5720A, with 2 input channels, a sampling rate of 250MS/s and a digitization over 12 bits, running a dedicate Digital Pulse Processing firmware for Charge Integration (DPP CI). As exemplary illustration, the spectrum of the photons emitted by the LED unit and recorded by a SiPM is shown in Figure 1. The light burst, with a duration at the ns level, is conveyed to the SiPM by an optical fiber, FC interfaced. The amplified signal from the SiPM is sampled by the CAEN Desktop Waveform digitizer. The integral of the pulse is retained as a figure of merit, actually implementing the functionalities of a digital QDC. Beyond the waveform digitization, the DT5720A performs the signal integration over different user-defined gating modalities, namely external or self-triggering, over a fixed or adaptive duration, the latter being defined by a threshold crossing. Figure 2 shows the dark count rate versus discrimination threshold obtained using the SP5600. Peaks corresponding to 24 photons can be resolved. Figure 2. One channel dark count rate versus discrimination threshold. Figure 1. Spectrum of the photons emitted by the LED unit and detected by a SiPM at room temperature. Peaks corresponding to 24 photons can be resolved. Set-up for SiPM testing & characterization VME NIM Desktop PCI Express - Digitizers Family From 1 to to 64 channels, up to 5 GS/s sampling rate FPGA firmwares for Digital Pulse Processing Up to 14 bit resolution VME64X, Optical Link, USB 2.0, PCI Express Interfaces available Memory buffer: up to 58MS/ch (max events) Multi-board synchronization and trigger distribution Software Tools for Windows and Linux

3 Application Detecting Gamma Rays The mini-spectrometer configuration is ideal for gamma ray detection. The spectrometer s design allows an easy connection to the General Purpose Amplifier and Power Supply Unit (SP5600). The signal produced by a crystal coupled with a 3x3 mm 2 SiPM is amplified by the SP5600 and then digitized by thecaendesktop waveform digitizer. In the spectrometer different crystals can be mounted. The Figure 3 shows the spectrum of a 137 Cs source obtained with a CsI crystal. Three different crystals are included in the kit (LYSO, BGO, CsI) to show how the different properties of these inorganic scintillators (Light Yield, Decay Time, Efficiency) affect the spectral response. 137 Cs spectrum obtained with a CsI crystal. The resolution on the 662 kev peak corresponds to a FWHM ~ 10% of the peak. Set-up for detecting gamma rays CAEN Waveform Digitizers feature Digital Pulse Processing (DPP) firmwares for physics applications. DPP algorithms are implemented in FPGA and can be reprogrammed at any time. In one single module you have the complete information and the capability to extract all the quantities of interest. FPGA fimware for Digital Pulse Processing - Zero Suppression - Pulse Triggering - Trapezoidal Filters for energy calculation - Digital Charge Integration - Digital CFD for timing information - Pulse Shape Analysis - Coincidence - Possibility of customization

4 Application Detecting Cosmic Rays and β particles The start-up kit may include a polystirene plastic scintillating tile with a sensitive volume of 100 x 100 x 10 mm 3, with light collected by a WLS fiber and conveyed to two SiPMs mounted on the SP5600. The signals from the first amplification stage of the SP5600 are routed to the discrimination stage, providing through a coincidence logic the trigger and the gate for digitizing the SiPM output. The discrimination and the coincidence can be also performed inside the FPGA of the Digitizer. Figure 4. Two channel coincidence rate versus discrimination threshold. The black data correspond to the random coincidence rate of the two sensors. The counting rate for a 90 Sr source of 3.7 kbq activity and for cosmic rays across the tile is also shown. The coincidence scheme naturally enhance the discrimination power against the background rate, as illustrated in Figure 4, where the counting frequency vs. the discrimination value in the SP5600 is shown. In the reported measurements, the sensors where equalized in gain and the coincidence window for the reported measurements was 50 ns. The spectrum for a 90 Sr source is displayed in Figure 5, with a most probable value corresponding to 6 photoelectrons for a 1x1 mm 2 sensor with 60% Photon Detection Efficiency. Figure Sr spectra acquired at two different threshold value. Set-up for detecting cosmic rays and β particles VME Desktop NIM PCI Express

5 CAEN Silicon Photomultiplier Kit The Kit comprises: Desktop Digitizer (DT5720A) Mod. DT5720A is a CAEN Desktop Waveform digitizer housing 2 channels 12 bit 250 MS/s ADC with a dedicated charge integrating firmware (DPP-CI) for real time pulse processing. This feature allows to perform on-line processing on detector signal directly digitized. 2 Channel 12bit 250 MS/s Digitizer Digital Pulse Processing for Charge Integration DPP-CI Best suited for PMT and SiPM/MPPC readout at low and high rates Mid-High speed signals (Typ: output of PMT/SiPM) Good timing resolution with fast signals (rise time < 100 ns) Optical Link and USB 2.0 interfaces Dimension: 154x50x164 mm 3 (WxHxD) 2 Channels General Purpose Amplifier and Power Supply Unit (SP5600) Mod. SP5600 is a General purpose Power Supply and Amplification Unit, integrating two SiPMs in a mother & daughter architecture allowing easy mounting and replacement of the sensors. The basic configuration features two channels with indipendent gain control up to 50 db and provides the bias voltage (up to 120 V) to the sensors with gain stabilization. Each channel can provide a digital output generated by the fast leading edge discriminators. A timing coincidence of the two channels is also available. Variable amplification gain (up to 50 db) Low noise, not to spoil the sensor performances for small signals Wideband, to comply with the fast sensor response Fast leading edge discriminator and time coincidence Provides the bias for the sensors with gain stabilization USB 2.0 interface Mechanical structures with two embedded SiPM 1 x 1 mm 2 Dimension: 150x50x70 mm 3 (WxHxD) Led Driver (SP5601) Mod. SP5601 is an ultra-fast LED Driver with pulse width at ns level, tunable intensity and frequency, that provides a low-cost tool for the detector characterization. The LED pulse generation can be triggered by an internal oscillator or by an external pulser. Width of pulse 3 60 ns LED color: violet (400nm) 1500 mcd Pulse generator: internal/external Optical output connectors: FC Optical fiber included Dimension: 70x30x110 mm 3 (WxHxD) Mini Spectrometer (SP5603) Mod. SP5603 is a mini-spectrometer for gamma ray detection. The spectrometer is composed by a mechanical structure that houses a scintillating crystal, coupled to a dedicated 3 X 3 mm 2 SiPM. Three crystals (LYSO, BGO, CsI) are also provided. The spectrometer s design allows an easy connection to the SP5600. Mechanical structure for optimal SiPM to crystal coupling Crystal dimensions: 3 x 3 x 15 mm 3 Included crystals: LYSO, BGO, Csl One SiPM 3 x 3 mm2 embedded Dimension: 40 mm (D), 35 mm (L) Scintillating Tile (SP5602) Mod.SP5602 is a plastic scintillating tile, with a WLS fiber embedded to collect the scintillator light, FC terminated. The tile, with a sensitive volume of 100 x 100 x 10 mm 3, is the ideal tool for tests with beta emitting isotopes and cosmic rays. Sensitive volume: 100 x 100 x 10 mm 3 Scintillator: polystyrene Light guide: embedded WLS fiber Output connectors: FC Dimension: 154x12x174 mm 3 (WxHxD)

6 Silicon Photomultiplier Kit Control Software CAEN developed a dedicated control software for the control of the Silicon Photomultiplier Kit. Through a simple graphical interface the user can manage all the parameters of both the Power Supply, the Amplification Unit and the Digitizer in a single window. With few easy steps the user can control the Bias and the Gain of the SiPM. The user can also easily modify the thresholds and the digital outputs. In the same window the digitized signals can be monitored, for a real time fine tuning of the set-up. Energy spectra, Charge Vs. Time and Staircase plots are also displayed in the plot tab. The possibility to save the data in two formats (ASCII and Binary) has been implemented for further data analysis. No programming required Simultaneous control of the digitizer and of the SP5600 Unit User friendly all-in-a window graphical interface Data saving in two formats: ASCII, Binary 4 plots available: Wave, Histogram, Charge Vs. Time, Staircase About us. CAEN SpA is acknowledged as the only company in the world providing a complete range of High/Low Voltage Power Supply systems and Front-End/Data Acquisition modules which meet IEEE Standards for Nuclear and Particle Physics. Extensive Research and Development capabilities have allowed CAEN SpA to play an important, long term role in this field. Our activities have always been at the forefront of technology, thanks to years of intensive collaborations with the most important Research Centres of the world. Our products appeal to a wide range of customers including engineers, scientists and technical professionals who all trust them to help achieve their goals faster and more effectively. CAEN S.p.A. Via Vetraia, Viareggio Italy Tel Fax info@caen.it CAEN GmbH Eckehardweg Solingen Germany Tel Mobile 49(0) Fax info@caen-de.com CAEN Technologies, Inc Bay Street - Suite 2 C Staten Island, NY USA Tel Fax info@caentechnologies.com CAEN Tools for Discovery Electronic Instrumentation For more information, visit our web site: Copyright CAEN spa. All rights reserved. Information in this publication supersedes all earlier versions. Specifications subject to change without notice SIPM_brochure_2.1_200910_ADOCUME00070