ELOG AIDA

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

AIDA

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Entry time:	Sat Mar 29 12:36:55 2025
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Offline analysis of AIDA R42_32. Degrader condition of F11 is with the same stopping power of e.g. R42_7 (see https://elog.ph.ed.ac.uk/AIDA/509). 5 mm Al between MUSIC 1 and MUSIC 2 3. + 0.2 = 3.2 mm Al on the upstream side of the PE wall Pb wall between MUSIC 1 and MUSIC 2 was reduced from 7.5 cm gap to ~6.5 mm gap (beam right side pushed in 1 cm, so asymmetric) (Variable degrader system remains unchanged with 1,2,3 in: 0.5 mm W + 0.3 mm W + 1.0 mm W (+3 mm Al backings)) * data items: 261088000 ( 118111.81 Hz) * ADC events: 36442207 ( 16485.84 Hz) * time warps: 0 ( 0.00 Hz) * DSSSD # 1 count: 5340742 old count: 5338849 dt: 304.98 s LEC rate: 17511.91 Hz * DSSSD # 2 count: 4962731 old count: 4960982 dt: 304.98 s LEC rate: 16272.43 Hz * DSSSD # 3 count: 2885062 old count: 2884042 dt: 304.98 s LEC rate: 9459.91 Hz * DSSSD # 4 count: 2336560 old count: 2335778 dt: 304.98 s LEC rate: 7661.41 Hz * DSSSD # 5 count: 2003149 old count: 2002489 dt: 304.98 s LEC rate: 6568.18 Hz * DSSSD # 6 count: 3645726 old count: 3644468 dt: 304.98 s LEC rate: 11954.07 Hz * DSSSD # 1 count: 56 old count: 56 dt: 304.98 s HEC rate: 0.18 Hz * DSSSD # 2 count: 62 old count: 62 dt: 304.98 s HEC rate: 0.20 Hz * DSSSD # 3 count: 87 old count: 87 dt: 304.98 s HEC rate: 0.29 Hz * DSSSD # 4 count: 60 old count: 60 dt: 304.98 s HEC rate: 0.20 Hz * DSSSD # 5 count: 37 old count: 37 dt: 304.98 s HEC rate: 0.12 Hz * DSSSD # 6 count: 9 old count: 9 dt: 304.98 s HEC rate: 0.03 Hz * ENTRY finish ends S O R T S T O P P E D ..... Thu Dec 1 11:06:21 2016 See attached histograms. Figure 1: The time structure of low energy events seems more normalized with a flat-top and similar intensity as like R41_2 (see i.e. https://elog.ph.ed.ac.uk/AIDA/507 ) rather than R42_32, though one wonders if this is a real effect or if R42_7 was somehow unusual. Figure 2: We can confirm that the number of real events corresponding to light ions seems reduced compared to R42_7 Fig 4. Figure 5: Distribution in XY of low gain [heavy ion / high energy] is still weighted to the right hand side as usual, but seems slightly more homogeneous than previous cases such as R42_7. This is corroborated by the scalers pasted above, where the implant rate to DSSD#3 is about 0.3 Hz rather than 0.4 Hz of R42_7; this is probably a real decrease and not merely a statistical effect as R41_2 also shows around 0.4 Hz. I conclude that heavy ion implant rate is reduced by about 1/3 from R42_7, most probably from the Pb bricks cutting some fraction of the beam (though in theory it could be from shifting 5 mm of the Al degrader up stream by ~2 m and the angular straggling of the heavy ions in the plate). Specific comparison of the implant rates show we are dropping 0.1 cps on DSSD#2, 0.1 cps on DSSD#3, and maybe 0.05 Hz (it's a sensible number or not different than zero?) in DSSD#4, which can give an idea of what ion species are being cut out if we looked at the BigRIPS PID correlated with AIDA implantation. Encoding: HTML ELCode plain Suppress Email notification

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