22Ne@131 MeV + 208Pb: a PRISMA+CLARA data analysis Paolo Mason

Part 1 From raw data to mass spectra

PRISMA+CLARA: the set-up Dipole Quadrupole Target Ionization chamber [IC] Start detector [MCP] Focal plane [PPAC] Rotating platform

PRISMA+CLARA: measured quantities - Time of flight → directly involved in calculation of speed, therefore of mass [mv2/R=qBv → m=qB•R/v] Q-value γ-ray energies (Doppler correction) Entrance and focal-plane space coordinates → used to reconstruct total distance D covered inside PRISMA (v = D/TOF) trajectory’s curvature radius R in dipole magnet Energy released in IC (each section) → used to select events (Z and q) γ-rays → (even when not of intrinsic interest, anyway) VERY useful to check Z, A attributions “calibrate” the TOF (Doppler correction) understand Q-value spectra.

The MCP (entrance) detector Three signals of interest: entrance X coordinate entrance Y coordinate TOF start Actions: noise removal “calibration” of X,Y signals MCP Y [a.u.] MCP Y [a.u.] MCP X [arb. units] MCP X [arb. units] coincidence with some focal-plane signal

Enhancing the focal-plane efficiency with the cathode signal 1/2 Light ions produce weak signals which may be cut by CFD thresholds → Need to use the cathode signal when the left or right signal is not there Establishing link between values of Xfp determined with/without Scathode 1083 3141 (Scathode-Sleft)/2 [a.u.] (Sright-Sleft)/4 [a.u.] Sec. #3 Removing cathode noise Scathode [arb. units] (Sleft+Sright)/2 [a.u.] Sec. #3 3000 987 Scathode/left/right = cathode/left/right signal

Enhancing the focal-plane efficiency with the cathode signal 2/2 PPAC section 1 2 3 4 5 6 7 8 9 Efficiency enhancement 1.6 2.1 2.5 2.2 1.7 5.7 1.5 1.4 R/v [arb. units] focal-plane X [mm] 1023 With cathode signal R/v [arb. units] focal-plane X [mm] 1023 Without cathode signal

Coarse matching of TOF offsets focal-plane X [mm] 1023 TOF [10-10 sec] arb. offsetS 2762 1382 PPAC sections have different TOF offsets → need to match them focal-plane X [mm] 1023 TOF [10-10 sec] arb. offset 2762 1382 …however, we may still have an arbitrary common TOF offset

Bquadrupole/Bdipole optimization (Bq/Bd)1/2=0.99 R/v [arb. units] (Bq/Bd)1/2=0.96 (Bq/Bd)1/2=0.93 72 1013 129 458 focal-plane X [mm] Xfp [mm]

Fine matching of TOF offsets & removal of common TOF offset Cuts from Xfp vs R/v D/R [arb. units] TOF [10-10 sec] arb. offset Xfp ≥ 900 800 ≤ Xfp < 900 700 ≤ Xfp < 800 600 ≤ Xfp < 700 500 ≤ Xfp < 600 400 ≤ Xfp < 500 300 ≤ Xfp < 400 200 ≤ Xfp < 300 100 ≤ Xfp < 200 Counts R/v [arb. units] (*) (*) Also check Xfp-R/v plot: a nonzero common TOF offset warps the (supposed-to-be) straight horizontal traces.

Energy release in IC [arb. units] Z selection Range in IC [arb. units] Energy release in IC [arb. units] Mg Na Ne F O

qB selection - a first qR/v spectrum DR/TOF [arb. units] Energy in IC [a.u.] Neon q=10+ q=8+ q=9+ mv2/R = qBv → mv2/2 = 1/2 qB Rv m = qB R/v qintR/v [arb. units] Z=10, qint=10 Z=10, qint=9 Z=10, qint=8 counts 22Ne (must be) 17.59Ne ??? Must be more careful in selecting events

Without (E/v2,R/v) bananas EIC/v2 vs R/v plots EIC/v2 [arb. units] R/v [arb. units] Neon EIC/v2 [arb. units] R/v [arb. units] Neon (E/v2,R/v) bananas give the possibility to remove spurious peaks. They may also serve as a tool to separate charge states. qintR/v [arb. units] Z=10, qint=10 Z=10, qint=9 Z=10, qint=8 counts Without (E/v2,R/v) bananas With (E/v2,R/v) bananas

Recognizing peaks - aligning R/v spectra R/v spectra corresponding to different charge states can be aligned just by a scaling (the scaling factor being, in principle, the charge). Z=12, qint=10 Z=11, qint=10 Z=11, qint=11 Z=12, qint=11 qintR/v [arb. units] counts (3) (1) A=23 from comparison with Z=10, qint=10 (*) spectrum (2) A=23 from comparison with Z=11, qint=10 spectrum (3) A=26 from comparison with Z=11, qint=10,11 spectra (2) (1) (3) qint 7 8 9 10 11 “qexp” (**) 7.22 8.15 9.08 ≡10 10.91 Once spectra corresponding to (common Z, but) different qint‘s are aligned, they can be summed and calibrated. (*) qint values are determined – comparatively – by looking at traces’ slopes in R•v vs EIC plot (**) If you find it downright outrageous to think of “fractional charges”, you might as well use integer scaling factors – along with nonzero offsets, though

One last check: Xfp vs mass 1424 3102 1023 Xfp [mm] 100 • mass [a.m.u.] Neon FWHM/centroid = 9.8•10-3

At last… mass yields Mg Na Ne Counts F O Mass [a.m.u.] A=26 101 103 25 26 27 28 counts 14 75 46 22 Mg 101 103 A=23 Na mass 23 24 25 26 counts 936 548 669 104 102 101 106 A=22 Ne mass 21 22 23 24 25 counts 2744 2.2e05 47623 9508 357 104 Counts 102 F A=21 103 mass 19 20 21 22 23 counts 94 837 4600 758 102 102 101 O A=20 102 mass 18 19 20 21 22 counts 268 301 598 63 8 101 Mass [a.m.u.]

A brief summary MCP detector: noise removal & “calibration” PPAC detector: usage of cathode signal to enhance efficiency Coarse matching of TOF offsets Optimization of Bquad/Bdip & fine matching of TOF offsets + Removal of residual TOF common offset Z selection Charge-state selection from R•v-EIC , E/v2-R/v plots Alignment of R/v spectra Calibration of qR/v spectra → mass spectra One needs not worry about scaling the TOF’s (to their “true” value) if he’s happy with mass spectra. But to get γ-ray energies and Q-values right he has to.

Part 2 Gamma spectra

Gammas in coincidence with Z=10, A=21 Eγ= 350 keV 45 counts Eγ= 777 keV 13 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=10, A=22 Eγ= 1275 keV 530 counts Eγ= 509 keV 95 counts Eγ= 583 keV 149 counts Eγ= 2613 keV Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=10, A=23 Eγ= 1770 keV 29 counts Eγ= 1704 keV 22 counts Eγ= 1016 keV 98 counts Eγ= 898 keV Eγ= 569 keV 321 counts Eγ= 492 keV 45 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=10, A=24 Eγ= 881 keV 20 counts Eγ= 537 keV 24 counts Eγ= 802 keV 80 counts Eγ= 2784 keV 6 counts Eγ= 1983 keV 42 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=11, A=23 Eγ= 440 keV 13 counts Eγ= 351 keV 10 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=11, A=25 Eγ= 204 keV 6 counts Eγ= 721 keV 4 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=9, A=20 Eγ= 167 keV 7 counts Eγ= 656 keV 8 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=9, A=21 Eγ= 1606 keV 9 counts Eγ= 896 keV 20 counts Eγ= 278 keV 26 counts Eγ= 822 keV 16 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Gammas in coincidence with Z=8, A=20 Eγ= 629 keV 6 counts Eγ= 245 keV 8 counts Eγ Doppler correction with βtarget-like Eγ Doppler correction with βprojectile-like Level scheme from NNDC ENSDF database

Part 3 Q-values

Mg Mass vs Q-value - Z=12 Mass [a.m.u.] -Q [MeV] A=25 26 27 28 22Ne+208Pb→ AMg+229-AHg + n -3.6 -4.1 -4.8 -Q=-5.7 MeV 22Ne+208Pb→ AMg+230-AHg -11.1 -10.1 -12.6 Q-values from NNDC Q-value calculator

Na Mass vs Q-value - Z=11 Mass [a.m.u.] -Q value [MeV] A=23 24 25 26 -Q=6.1 MeV 5.6 5.2 4.1 22Ne+208Pb→ ANa+229-ATl + n 22Ne+208Pb→ ANa+230-ATl -Q=-0.8 MeV -0.9 -1.4 -3.4 Q-values from NNDC Q-value calculator

Ne Mass vs Q-value - Z=10 Mass [a.m.u.] -Q value [MeV] A=21 22 23 24 25 Ne -Q=10.4 MeV 10.6 22Ne+208Pb→ ANe+229-APb + n 8.9 7.4 8.1 22Ne+208Pb→ ANe+230-APb -Q=6.4 MeV 3.9 2.2 0.0 0.04 Q-values from NNDC Q-value calculator

F Mass vs Q-value - Z=9 Mass [a.m.u.] -Q value [MeV] A=19 20 21 22 23 -Q=21.6 MeV 21.1 22Ne+208Pb→ AF+229-ABi + n 19.6 20.6 18.9 -Q=16.4 MeV 22Ne+208Pb→ AF+230-ABi 15.0 13.7 13.0 11.5 Q-values from NNDC Q-value calculator

O Mass vs Q-value - Z=8 Mass [a.m.u.] -Q value [MeV] A=17 18 19 20 21 22 O -Q=26.7 MeV 30.0 28.4 22Ne+208Pb→ AO+229-APo + n 25.2 25.3 24.6 22Ne+208Pb→ AO+230-APo -Q=22.3 MeV 21.5 21.6 20.7 18.6 17.6 Q-values from NNDC Q-value calculator

Q-value vs Gammas - Z=8, A=20 selection Eγ=1968 keV -Q=28.5 MeV -Q=13.0 MeV Eγ=0 keV Eγ= 629 keV 210Po 8+→8+ Eγ= 245 keV 210Po 4+→2+ -Q [MeV] Eγ [keV] target-like Doppler Eγ=1968 keV 32 counts 29 counts Eγ [keV] target-like Doppler Eγ=0 keV -Q=7.5 MeV -Q=25.3 MeV -Q=53 MeV -Q value [MeV] 22Ne+208Pb → 20O+209Po+n corresponds to Q-value = -25.3 MeV [NNDC]

Signature of one-neutron evaporation following one- or two-neutron pick-up -Q ≥ 9.5 MeV -2.0 ≤ -Q ≤ 9.0 MeV Eγ [keV] target-like Doppler counts Selection: Z=10, A=23 207Pb 5/2-→1/2- 570 keV 207Pb 3/2-→1/2- 898 keV 207Pb 7/2-→5/2- 1770 keV 206Pb 2+→0+ 803 keV 2n pick-up 1n pick-up 23Ne 206Pb 22Ne+208Pb → 23Ne+206Po+n corresponds to Q-value = -8.9 MeV [NNDC]

Understanding the Q-value spectrum in coincidence with the detection of 22Ne -5 -10 -15 5 10 15 20 25 30 35 40 45 Q-value [MeV] counts 101 103 102 104 Maximal EIC Coincidence with CLARA -3.5 ≤ -Q ≤ 1.0 MeV 3.5 ≤ -Q ≤ 7.0 MeV 7.5 ≤ -Q ≤ 36.0 MeV 22Ne 2+→0+ wrong Doppler 208Pb 3-→0+ 2615 keV 208Pb 51-→3- 583 keV 208Pb 52-→51- 511 keV Eγ [keV] target-like Doppler counts 207Pb 5/2-→1/2- 570 keV 208Pb 583 keV 208Pb 511 keV Eγ [keV] counts 22Ne+208Pb → 22Ne+207Pb+n corresponds to Q-value = -7.4 MeV [NNDC]

The end Thank Nicu for training additional programming standing the hassle that I gave to him The end

2n pick-up 1n pick-up 23Ne 206Pb