next up previous contents
Next: Trigger Up: Detection System Previous: Detection System

Overview

As illustrated in Sec 1.2, muonic processes in hydrogen isotopes produce a rich variety of complex reactions, leading to various kinds of radiations. Obviously, detecting as many different types of radiation as possible is advantageous in identifying and understanding the processes. The TRIUMF system was designed to allow this versatility.

Figure 3.17 illustrates a top view of a detector arrangement used in Run Series 1. Muons entering the system were detected by a thin plastic muon beam counter (T1).  On the beam right (i.e., on the right hand side when facing the same direction as the beam flux) was placed a set of MWPCs, which tracked trajectories of muon-decay electrons, enabling measurement of the positions and the time of muon decay. A silicon detector and a neutron detector detected fusion products, while a germanium detector monitored target impurities via muonic X-rays. Si detecter was placed in vacuum, and held on the side of the heat shield, viewing the targets without any window in bewteen. Electron, Neutron and Ge detectors were placed outside the safety enclosure (Section 3.2.5), which contained the vacuum system.


 


 

For Run Series 2 (Fig. 3.18), the distance between the two gold foils was reduced to 17.9 mm from 42.5 mm in order to enhance the number of lower energy $\mu t$atoms surviving to reach the downstream reaction layer. Because of the smaller drift distance, the MWPCs, which had a position resolution of several mm, were not useful and they were replaced by a silicon detector and neutron detector to gain better efficiency for fusion product detection.

 Detector signals were processed via a NIM/CAMAC electronics system. The signals were converted with Analog-to-Digital Converters (ADCs) or Time-to-Digital Converters (TDCs) modules and read into a workstation (DEC Vax Station) with a TRIUMF developed VDACS data acquisition system [196]. The VDACS uses a PDP-11 microprocessor (CES 2180 Starburst, hereafter called a Starburst) as a front-end-processor which handles the data acquisition according to a procedure specified by the user using a high level language called TWOTRAN [197]. The data were logged onto a magnetic tape on an event by event basis for off-line analysis, while an analysis program MOLLI [198] was used for on-line analysis to provide a rapid diagnosis of the experiment.


next up previous contents
Next: Trigger Up: Detection System Previous: Detection System