Fe55 peak shape

Fe55 with 50/50 Ar/CO₂, New preamp and new HVB, ADC half-range

Mixed 50/50 at 40 sccm total, moved the source (collimated as usual) across the top of the straw towards the edge....

max amplitude histo for 55Fe mixed 50/50 at 40 sccm

energy histo for 55Fe mixed 50/50 at 40 sccm

With the source over the edge of the straw, the count rate halves and the camel disappears.

max amplitude histo for 55Fe (side of straw) mixed 50/50 at 40 sccm

energy histo for 55Fe (side of straw) mixed 50/50 at 40 sccm

Overlaying side and edge data, the light coloured plots are with the source above the wire.

max amplitude histo for 55Fe mixed 50/50 at 80 sccm

energy histo for 55Fe mixed 50/50 at 80 sccm