The NA48 LKr calorimeter digitizer electronics chain

Abstract

The 13 500 channels of the NA48 liquid-krypton electromagnetic calorimeter readout electronics were put into operation in 1997. The digitizer electronics employs a new gain switching technique that expands the dynamic range of a standard 10-bit ADC to 14 bits at 40 MHz sampling rate employing a custom-developed integrated circuit (KRYPTON). The KRYPTON has been fabricated in 1.2 µm BiCMOS technology and was successfully developed together with industry on a short timescale. The performance and the experience from the first year of the operation of the liquid-krypton calorimeter electronics will also be briefly discussed.

The trigger for K0→π0π0 decays of the NA48 experiment at CERN

“…The CPD module is used to shape, digitise and store the calorimeter signals, and to read them out when an event is triggered [5]. The shaping produces a pulse from only the rapid initial rise of the current from the calorimeter signals.…”

RISC mezzanines for controlling data acquisition in the NA48 experiment at CERN

“…Each cell is connected to a preampli"er/shaper operating at nitrogen cryogenic temperature, followed by a transceiver for the long distance analog di!erential signal transmission. Analog signals from these cells are constantly digitized by #ash ADCs and temporarily stored (CPD stage) [7]. Time window of interest for a sample is copied and funneled into a pipelined zero-suppression "lter (DC stage).…”

“…The CPD stage consists of 216 custom CPD modules [7]. Each CPD contains the electronics to continuously shape and digitize 64 inputs in parallel.…”

Towards results on direct CP violation in Kaon decays from the CERN-SPS experiment NA48

“…The geometry of the calorimeter points to the centre of the K L , K S decay region ∼ 110 m upstream. The calorimeter is read out by FADCs at 40 MHz sampling frequency [9]. The energy resolution of the calorimeter is better than 1 % for photons above 20 GeV.…”