DCH preamplifier developments In Montreal J P Martin

DCH preamplifier developments In Montreal J. P. Martin, Paul Taras, Nikolai Starinski, Y. Landry 12/16/2021 J. P. Martin, 5 th Super. B meeting 1

DCH cell simplified electrical model HV 380 Z 0 = 380 ohms Lossy 1 Lossy 2 Preamp Zpreamp Current pulse from cluster Example: 50, 000 electrons in 1 nanosecond = 8 µA => 1. 52 millivolts in 380/2 ohms 12/16/2021 J. P. Martin, 5 th Super. B meeting 2

Optimizing with different values of Zpreamp Input signal ≈ Zpreamp/(Zpreamp + 380) Input noise ≈ (Zpreamp)(1/2) Input Relative Impedance signal 50 180 380 12/16/2021 0. 116 0. 321 0. 5 Relative S/N input noise 1 1. 66 2. 75 0. 116 0. 193 0. 181 J. P. Martin, 5 th Super. B meeting Comments Best bandwidth Could match PCB traces Matches DCH cell 3

The 50 ohms preamplifier prototype: Uses two very small size commercial RF gain blocks ( Analog Devices AD 8354) Nominal Gain : 20 d. B (each gain block) Bandwidth : 1 MHz to 2. 7 GHz Noise figure : 4. 2 d. B Operating voltage: 3 to 5 Volts Measured output RMS noise of the preamplifier: 2. 08 millivolts RMS Measured overall gain with a 50 ohms source : 65 Theoritical thermal noise at 1 GHz bandwidth with noiseless amplifier 12/16/2021 J. P. Martin, 5 th Super. B meeting : 1. 84 millivolts RMS 4

The 50 ohms preamplifier prototype: Input circuitry To 50 ohms Gain block (changed to 1 u. F) Protection diodes HV blocking capacitor Note: RC = 90 nsec Note: parallel input capacitance: 2 pf. 12/16/2021 J. P. Martin, 5 th Super. B meeting 5

The 50 ohms preamplifier prototype: Gain block X 2 Y low inductance capacitor 12/16/2021 J. P. Martin, 5 th Super. B meeting 6

The 180/380 ohms preamplifier front end prototypes: Prototype has two separate PCBs: one 50 ohms amplifier one front end buffer card with a BFG 425 W transistor in voltage follower configuration: Transition frequency : 25 GHz Feedback capacitance : 95 f. F DC current gain (β) : 80 Measured output RMS noise of the preamplifier combo: 3. 3 millivolts RMS (with Zin = 380 ohms) 12/16/2021 J. P. Martin, 5 th Super. B meeting 7

The 180/380 ohms front end prototypes: Front end circuitry Note: RC = 684 nsec. 12/16/2021 J. P. Martin, 5 th Super. B meeting 68 n. Hy with 380 ohms 15 n. Hy with 170 ohms 8

The 180/380 ohms Front end prototype: Voltage follower 50 ohms cable 12/16/2021 J. P. Martin, 5 th Super. B meeting 9

The 180/380 ohms integrated preamplifiers: Prototype has a single PCBs: two 50 ohms gain block chips one front end BFG 425 W transistor either in unity gain voltage follower configuration or in Gain = 2 inverting amplifier Measured noise (at TRIUMF): Follower : 1. 9 millivolts RMS Inverting : 2. 4 millivolts RMS 12/16/2021 J. P. Martin, 5 th Super. B meeting 10

The 180/380 ohms integrated Front end: Voltage follower Changed to 100 ohms Removed Inverting Non inverting To gain block Changed to 27 Kohms Changed to 50 ohms 12/16/2021 J. P. Martin, 5 th Super. B meeting 11

Beam data analysis by J. F. 12/16/2021 J. P. Martin, 5 th Super. B meeting 12

To be developped: Multi channel preamplifiers 12/16/2021 J. P. Martin, 5 th Super. B meeting 13