Peter, Wieczorek - EE Low Noise Charge Sensitive Preamplifier Development for the PANDA Calorimeter Design and Measurements of the APFEL - Chip

Peter, Wieczorek - EE Outline 1. PANDA – Experiment Overview 2. Design of the APFEL – Chip 3. Measurements of the ASIC – Performance

Peter, Wieczorek - EE 1. The PANDA-Experiment

Peter, Wieczorek - EE PANDA - Experiment PANDA

Peter, Wieczorek - EE Physical Goals The aim of the PANDA – experiment is the better understanding of the strong interaction as well as the structure and dynamics of hadrons Studies of bound quarks using meson spectroscopie  Bound qq – states  Theoretical description by QCD Looking for exotic states Hybrids (qqg) Glueballs (ggg) Molecule Molecules Gluons Mesons p Momentum [GeV/c] Mass [GeV/c 2 ]

Peter, Wieczorek - EE Charmonium Spectra Charmonium: cc – quarks Spectra of exicited states Activation of all states by pp – interaction Search of the theoretical predicted mesons Detection of charged and neutral particals over the whole solid angle p Momentum [GeV/c] [GeV/c] Mass [GeV/c 2 ]

Peter, Wieczorek - EE PANDA - Detector Target Solenoid Dipol STT RICH EMC HC Myondetector EMC MVD DIRC STT p

Peter, Wieczorek - EE Electromagnetic Calorimeter Photon detection by the electromagnetic calorimeter crystals (Barrel) Used scintillator material: PbWO 4 To increase the crystal light yield the calorimeter will operate at a temperature of T = - 20°C

Peter, Wieczorek - EE Scintillator Material Photon e - e - e + e + ….. ? Output Voltage Readout Electronics Avalanche Photodiode Scintillator Crystal λ max = 430 nm

Peter, Wieczorek - EE Requirements Noise: ENC = 4500 e - ( ≈ 0,7 fC) Max. input charge: Q max = 7 pC Dyn. range: Event rate: ≈ 350 kHz Avalanche photodiode: Detector capacitance: C det = 300 pF Dark current: I d = 50 nA at M = 50 Operation Temperature: T = -20°C Power dissipation: P < 60 mW/Channel Very compact calorimeter design  High integration level of the readout electronics Development of an application specific integrated circuit Development of an application specific integrated circuit

Peter, Wieczorek - EE 2. APFEL - Chip Design (Asic for Panda Frontend ELectronics)

Peter, Wieczorek - EE Noise Calculations Preselection of the free parameters: W = µm, I ds = 2 mA and  = 250 ns W I ds  Area ~ Signal Noise Feasibility study for integrated calorimeter readout electronics The dominant noise source is the input transistor Transistor noise is a function of Transistorwidth W Current I ds Integration time 

Peter, Wieczorek - EE Readout Concept Readout is realized in three stages First readout stage is a low noise Charge Sensitive Amplifier (CSA) based on a folded cascode circuit Second stage consists of a differentiator and three first order integrators Semi gaussian pulse form Improvement of the Signal-to-Noise-Ratio (SNR) The last stage is an output/line driver, which can cope with a load of 10 pF || 50 kΩ

Peter, Wieczorek - EE Concept of the Readout Electronic - Charge Sensitive Amplifier Output Stage Shaper Stage Preamp First Shaper Second Shaper Third Shaper

Peter, Wieczorek - EE Chip Overview Shaper Stage Output Stage Charge Sensitive Preamplifier Channel 1 Channel 2 Voltage References Used prozess: 350 nm - CMOS Dimensions: 3,3 mm x 3,3 mm Pins: 64 Components: Transistors: 4841 Capacitors: 1729 Resistors: 386

Peter, Wieczorek - EE 3. Chip Characterisation

Peter, Wieczorek - EE PCB for the ASIC Characterisation For the characterisation of the ASIC a PCB was designed Power supply (Vddc,Vddt): 3.3 V For measurements a voltage step ΔV injected to a coupling capacitance With the voltage step ΔV and the capacitance C in the injected input charge can be calculated to Q in = C in ΔV

Peter, Wieczorek - EE Cooling For cooling an external controlled Peltier-Element is used Measurements in the range of T=-20°C up to T=+20°C could be realized The current ASIC temperature is measured by a PT100 InputOutput Cooper Peltier Element PT100

Peter, Wieczorek - EE Measurement Setup (1) Measurements are performed in an evacuated environment Water cooling for heat sinking Electrical connections are done via BNC - connectors

Peter, Wieczorek - EE Measurement Setup (2) Power Supply Signal Generator AWG Programming Oscilloscope Temperature Controller PCB Defined input step ΔV by an AWG Measuring the output pulse characteristics at Different temperatures Different detector capacitances

Peter, Wieczorek - EE Output Pulse Amplitude & Rise time Noise

Peter, Wieczorek - EE Measured Results Requirements: Results at T = - 20° C Unit: Noise: ± 35 e-e-e-e- Max. input charge: 77,84 pC pC Dyn. range: Integration time: ± 3 ns Max. event rate: kHz Power: < ± 1 mW

Peter, Wieczorek - EE Status The developed APFEL- chip fulfills all requirements First preliminary radiation tests have been done Next steps More detailed radiation tests are necessary Readout of an array of crystals

Peter, Wieczorek - EE Thank you for your attention