6.1.1 ATC Event Size

6.1 On-line Software

6.1.1 ATC Event Size

The ATC readout consists of 84 readout channels (Section 5.2) which are digitized by TDC's. Each TDC card has two TDC chips with 8 inputs (total 16 inputs per card). One of the inputs us reserved for the trigger while the remaining seven inputs are connected to SBBC cards. There are six SFEC cards allocated to the readout of the ATC.

For every SBBC channel the SFEC provides two 16-bit words: the rising edge time and the falling edge time. We need an additional byte-long word to store the geographic id of the fired SBBC. Therefore, assuming that on a typical electron event 4 PMT's are firing, we expect to have:

. . . 6-1

In addition, we expect to have 10% of noise hits due to the low threshold of the comparators. The low threshold is required in order to maintain a good rejection efficiency on electrons (Section 2.5). The noise is expected to increase the event size by approximatelly 30 bytes.

Therefore, the total event size of the ATC is expected to be of the order of 50 bytes [6-1].

Issue: Draft - Revision: 04 - Last Modified: 20 April 1997