Development of triggered scaler to detect missing trigger

In the timing system of J-PARC MR, trigger signals are generated and delivered to accelerator components, for example, a power supply or a beam diagnostic device. The machine cycle of J-PARC MR is 2.48s in FX-mode, or 5.52s in SX-mode. Each component receives one trigger per the machine cycle. During beam operation, when we detect an unexpected behavior of beam, we often discuss a miss-trigger to be an origin of such the behavior. Although we can confirm parameter settings of timing triggers, there is no read-back system to check trigger signals at end components. A 'Triggered Scaler' is a scaler to count trigger signals. It stores counts in a memory array, and each external 25Hz input shifts the pointer to the array. For the MR cycle 2.48s (5.52s), 62 (138) elements are used in an array. At a normal time, '1' is set in an element among the other '0' value elements. But when a miss-trigger occurs, all elements become '0'. A prototype of 'Triggered Scaler' is developed. In this paper, we report a demonstration using trigger signals of MR. (author)