BCTF Distribution Amplifier and Calibration Electronics Distribution Amplifier
BCTF Distribution Amplifier and Calibration Electronics
Distribution Amplifier • Movement from DAB to FMC digitisation • Intensities up to 3 e 11 particles • Input Signal level per bunch • Pilot – 300 m. V • Ultimate – 15 V (Expected) • ADC Full scale – 410 m. V • Max Input Voltage – 1 V BCTF Transformer Calibrator Distribution Amplifier Spare FMC Card Scope
Distribution Amplifier High Level Design
Distribution Amplifier - Output Voltage Clamping THS 3001 Measured saturation ~3 V Max Voltage ~750 m. V
Distribution Amplifier – Amplifier Input Voltage Limiting ± 15 V +0. 5 V -0. 5 V ± 5 V
Distribution Amplifier – Amplifier Input Voltage Limiting • Schottky diodes used to limit input voltage exceeding second stage amplifier supply rail voltages • Diodes biased above full scale value of ADC • Limit leakage current • Once diodes conduct – low impedance path to GND
PCB & Features • Compatibility with BCTW • Option to independently power amplifier stages with ± 15 V or ± 5 V • First stage amplifier can be bypassed • Multi-input configurable
Frequency Response – Low Gain High Cut Off
Frequency Response – High Gain High Cut Off
Frequency Response – High Gain Low Cut off of BCTF is between 0. 32 – 1. 6 k. Hz https: //www. bergoz. com/sites/www. bergoz. com/files/fctdatasheetv 4. 9 -web
Frequency Response – Low Gain Low Cut off
High Frequency Cut off Comparison
Low Frequency Cut off Comparison
Pulse Response – Pilot - 5 e 9 Charges
Pulse Response – Nominal- 1 e 11 Charges
Pulse Response – Ultimate– 3 e 11 Charges
Noise • Measured using 12 bit 1 GHz Lecroy Teledyne HDO 6104 Oscilloscope • Input terminated with 50Ω load • Time division set to 20 ms • Data taken when average standard deviation is stable to 3 decimal places • Noise of oscilloscope taken into account • Calculated using root sum of squares method
BCTF Calibration
BCTF - Calibrator • Current situation - 128 m. A for 5µS • Proposal to increase calibration current • Research into high voltage calibrator Current (m. A) High Gain (% of FSV) Low Gain (% of FSV) Achievable with current system 128 19. 51 1. 64 Yes 200 30. 49 2. 57 Yes 300 45. 73 3. 85 Yes 600 91. 46 7. 70 No
High Level Design • • • Current set – Vref/Rref BCTF Rload – 50 Ω RRef (0. 05 ppm/℃) and (4 ppm/W) Vcc – 24 V Max Current • Max Limit - 380 m. A • 20% Compliance voltage margin 300 m. A
Half Bridge • Half Bridge uses 0 V measurement method • Signal is amplified and digitised • Vref Adjusted until 0 V measured • DAC and on-board POT • Vref digitised by 24 Bit ADC
PCB Design Current Source Acquisition and Control Input Power Output Voltage Reference Half Bridge
Calibration – Method 1 Current Pulse Transformer Response Interpolate to t = 0
Calibration – Method 2 • Current Pulse Transformer Response
Operation • Rolling current measurements are made by on-board FPGA • The calibration voltage reference value is returned to VFC card • Calibration constant calculated on VFC • Calibrator is triggered by 4 LEMO inputs • triggering up to 4 outputs • Remote voltage adjustment made through I 2 C interface.
- Slides: 25