FADC progress in Vienna Reported by H.Ishino for Vienna FADC group M.Pernicka and H.Steininger

Tests at Vienna Y.Ushiroda (KEK) H.Ishino (T.I.T.) Data transfer from FADC to PPCI Tests for cable cross talk Other topics related with FADC

Data transfer from FADC to PPCI The data transfer was successfully done with the 10MHz clock. However, with 20MHz we had a problem. –The first 32 bit datum which has a start bit was dropped, because the PPCI board needs 80nsec to be ready for receiving data. –To solve the problem, we dropped the first clock signal. –Data are transferred successfully. (we performed a long time test for about 12 hours. No error was detected.) –This may be a potential problem, i.e. a big external noise would cause read out error under real situation.

XVALID (FADC asserts) 10MHz clock 100nsec Data 80nsec This datum is not valid 20MHz clock Data 50nsec

Read out test with a pulse generator A pulse generator FADC board PC (Linux7.1) data 10bit FADC TTM trigger (1kHz) ADC start Signal input

Read out test with a pulse generator was successfully done.

Checks for cross talk between twisted 30m cables Single shield Double shield Pair shield No shield 5MHz clock signals One of twisted cables The other of the twisted cables Differential of the twisted cables No cross talk was detected

FADC status The present Data format 32 bits Start bit (1 bit) Event counter from TTM (4 bits) ADC 10 bits Stop bit (1 bit) ADC 10 bits 128/ch Lower half part of FADC Upper half part of FADC th 127th We need not duplicate EV counter, start/stop bit. We requested to Vienna group to replace the one of EV and start/stop bit to channel # (4bit) and parity bit.

FADC status The Data format we request 32 bits Start bit (1 bit) Event counter from TTM (4 bits) ADC 10 bits Stop bit (1 bit) ADC 10 bits 128/ch Lower half part of FADC Upper half part of FADC th 127th Channel # (4 bits) Parity bit (1 bit)

L0 trigger L0 processor (Altera chip) was already mounted on a FADC board. The program which decides trigger issue by looking at combinations of TA outputs is being developed. If L0 processor issue trigger, a 50nsec width NIM signal and a 120nsec width ECL signal are generated. By Karawatzki-san (Vienna)

How the L1.5 trigger is implemented (outside of FADC) We need information of pedestal and noise levels to set a threshold level. Those levels are obtained from a sparcification process running on a PC which collects raw data from FADC boards. FADC boards PC (Linux) Sparc board (CPU50?) Raw data Sparcification process Reduce data size and calculate noise and pedestal NSM (Network Shared Memory) Write threshold levels to registers via VME bus

How often should we update the threshold levels? By Takeshita san (Osaka U) noise pedestal Right figures are time variations of noise and pedestal during a run (run#57, exp.17). Noise decreases by about 6%, while pedestal is almost stable. If we require 5% precision, we need to update the thr. Level one or two times during a run. This estimation came from SVD1.4. Of course the situation of SVD2.0 would be different.

Schedule of FADC Vienna group will send their system (FADC board, back board, VME crate and power supply) to KEK on middle of Mar. The full production of FADC boards will start on the end of April and finish on the end of July(?).

L1.5 trigger (inside of FADC) Registers for a threshold level of each channel have been prepared already. Reading/writing data from/to the registers via VME bus using a sparc CPU board was successfully done. The output signal of L1.5 trigger Ch 1 Ch 2 Ch 3 Ch 4 50nsec delay 100nsec delay 150nsec delay 50nsec 20MHz clock L1.5 output I am not sure for further more details about cable connection and so on.