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:

Thu Dec 1 02:25:41 2016

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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.

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