A gas microstrip wide angle X-ray detector for application in synchrotron radiation experiments

The OSMOND detector

“…As mentioned above, the plate is designed to point at the sample position; this non-uniform electrode structure can introduce non-uniformities in the gain of the MSGC along the strip length. Previous work has shown that this non-uniformity can be minimised by carefully grading the anode-cathode gap width with the pitch of the tracks [21] using the empirically determined formula given in [22]. The plates have been designed accordingly and because the tapering on the plates is not too severe (cathode width varies by 7 mm over the active length) the gain variation from the front to the back is acceptable.…”

The HOTWAXS detector

“…The range of potential applied to the drift to achieve this was À3000 to À4200 V for an 18 mm drift depth. Results from the prototype detector for HOTWAXS [11] also highlighted two other areas where careful attention to the drift space geometry and field pattern would benefit the detection properties of the HOTWAXS detector. These were a re-entrant window and some side field-shaping electrodes.…”

“…The HOTWAXS MSGCs are of the 'pointing anode' design described previously [6], thus offering a parallax-free geometry. Each glass plate consists of 128 anodes of 10 mm width and 50 mm in active length.…”

“…Previous work has shown that this non-uniformity can be minimised by carefully grading the anode-cathode gap width with the pitch of the tracks [10] and by using the empirically determined formula given in Ref. [6],…”

“…2. This radial gain variation can be removed further by using a graded drift electrode [6], which reduces the variation to 2%; see Fig. 1.…”