Magnetic tape digital recording for nuclear research

The paper describes two magnetic tape digital recording techniques developed for nuclear physics research. Both 1 in. 16-track and ¼ in. 4-track systems are used with maximum bit packing densities of 200 and 400/in, respectively. The tape writing and reading technique uses a return to zero method chosen to facilitate “drop out” detection; a “0” is written by a short duration current pulse of one polarity and a “1” but a similar pulse of reverse polarity. The absence of a pulse on any track during reading indicates a “drop out” and the particular event is then rejected. This error check permits the use of tape systems with overall drop out performance as bad as 1 in 160 bits.