Cosmic Ray Isotopes measured by AMS F. Giovacchini - CIEMAT on - - PowerPoint PPT Presentation

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Cosmic Ray Isotopes measured by AMS F. Giovacchini - CIEMAT on - - PowerPoint PPT Presentation

Nov 22, 2022 354 likes •613 views

Cosmic Ray Isotopes measured by AMS F. Giovacchini - CIEMAT on behalf of the AMS-02 collaboration Light Isotopes on Cosmic Rays Precise measurements of chemical composition of CRs with AMS (See M.P and V.F) provide important information for

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SLIDE 1
  • F. Giovacchini - CIEMAT
  • n behalf of the AMS-02 collaboration

Cosmic Ray Isotopes measured by AMS

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SLIDE 2

Light Isotopes on Cosmic Rays

Isotopes in light cosmic rays

F.Giovacchini 2

More detailed description from Isotopic composition:

  • D/p: secondary/primary with D mainly from 4He
  • 3He/4He:

4He mainly produced and accelerated in sources

(prim.);3He mainly produced by collision of 4He with the ISM (sec.). à Unique probe for propagation

  • 6Li/7Li: both mainly determined by the secondary

production cross sections from C, N, O fragmentation. Light secondary like D, 3He and Li probe the properties of diffusion at larger distance than heavier secondary like B.

  • 10Be: complementary tool relevant to estimate the

residence time of CRs in the galaxy:

10Be: t1/2 = 1.4 My, comparable to the average CRs

lifetime

TAUP2019, Toyama

Precise measurements of chemical composition of CRs with AMS (See M.P and V.F) provide important information for understanding the origin and propagation of CRs in the galaxy;

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SLIDE 3

F.Giovacchini 3

Isotopic composition with AMS

L1 L2 L3,L4 L5,L6 L7,L8 L9

TRD ECAL MAGNET

Z measurement: L1 - UTOF - Inner Tracker - LTOF à Negligible misidentification R measurement: Tracker (Inner), R=p/Z ΔR/R(R<20 GV)~10%

TOF Lower TOF Upper RICH

LTOF UTOF

L2-L8: Inner Tracker

β Measurement: TOF RICH

TAUP2019, Toyama

m = ZR / βγ

βγ

σ(m)/m = σ(R)/R ⊕ γ2 σ(β)/β

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SLIDE 4

2 4 6 8 10

Z

0.5 1 1.5 2 2.5 3 3.5 4 4.5

3 −

10 ×

β

σ

Δβ/β2 ≈ 4% for Z=1, 2% for Z=2 and 1%-2% for Z>2

F.Giovacchini 4

Isotopic composition with AMS

TAUP2019, Toyama

NaF Aerogel Mirror PMT matrix

UPPER TOF LOWER TOF

PLANE 2 PLANE 1 PLANE 4 PLANE 3

Velocity from TOF: Velocity from RICH (2 radiators):

RICH-NaF (β>0.75): Δβ≈0.35% (Z=1) and Δβ<0.25% @ β~1 (Z>1) RICH-Agl (β>0.96): Δβ≈0.12% (Z=1) and Δβ<0.07% @ β~1 (Z>1)

RICH TOF

D,p He Li

Be

Δβ

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SLIDE 5

F.Giovacchini 5

Deuteron identification with AMS

TAUP2019, Toyama

à Analysis in 3 different energy ranges

TOF β range, Ekin: 0.45 GeV/n from MC simulation

  • To identify the isotopes: Mass

templates are obtained from MC simulation of D and p

  • Contamination from interaction

inside the detector accounted from MC, validated with direct measurement in AMS

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SLIDE 6

F.Giovacchini 6

D

  • D/p ratio vs Ekin per nucleon

à Extends the measurement up to 10 GeV/n

Preliminary data, refer to upcoming AMS PRL publication Preliminary data, refer to upcoming AMS PRL publication TAUP2019, Toyama

  • First precision measurement of D above

1 GeV/n

0.2 0.3 0.4 0.5 0.60.70.8 0.91 2 3 4 5 6 7 8 9

Ekin [GeV/n]

0.02 0.04 0.06 0.08 0.1 0.12

D/p ratio

BESS00(2000/08) CAPRICE94(1994/08) IMAX92(1992/07) PAMELA-CALO(2006/07-2007/12) PAMELA-TOF(2006/07-2007/12)

Ekin [GeV/n]

D/p

AMS (2011-2016)

Deuteron Flux and D/p

Flux [(m2 sec sr GV-1)-1]

Ekin [GeV/n]

Preliminary data, refer to upcoming AMS PRL publication Preliminary data, refer to upcoming AMS PRL publication

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SLIDE 7

Helium is the second most abundant specie in CRs To identify the isotopes:

  • Unfold the momentum distribution, within the beta

bin, using the tracker resolution function to get 3He and 4He peaks and count events on TOP of AMS.

  • Fold back the results and Fit to the data.

F.Giovacchini 7

1 2 3 4 5 R [GV] 1 10

2

10

3

10

4

10

5

10 Events

a)

4 6 8 10 R [GV] 1 10

2

10

3

10

4

10 Events

b)

5 10 15 20 25 R [GV] 1 10

2

10

3

10

4

10 Events

c)

1 2 3 4 5 R [GV] 1 10

2

10

3

10

4

10

5

10 4 6 8 10 R [GV] 1 10

2

10

3

10

4

10 5 10 15 20 25 R [GV] 1 10

2

10

3

10

4

10

Helium Isotopes identification with AMS02

TOF RICH,NaF RICH, Agl

0.8149 < β < 0.8160 0.9532 < β < 0.9537 0.9863 < β < 0.9864

3He 4He

Data Fit

3He 4He

Data Fit

3He 4He

Data Fit TAUP2019, Toyama

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SLIDE 8

2 4 6 8 10

[GeV/n]

K

E

0.1 0.15 0.2 0.25 0.3

He

4

Φ /

He

3

Φ

AMS-02 PAMELA-CALO PAMELA-TOF IMAX-92 BESS-98 BESS-93 GALPROP

3He/4He vs Ekin

F.Giovacchini 8 TAUP2019, Toyama Submitted to PRL refer to upcoming AMS publication

Data: 6.5 y (05/2011 to 11/2017)

4He: 100 million 3He: 18 million

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SLIDE 9

2011 2012 2013 2014 2015 2016 2017 2018 0.095 0.1 0.105

e) 14.10 < R < 15.30 GV

2010 2012 2012 2013 2014 2016 2016 2017 0.13 0.14 0.15 0.16

d) 4.02 < R < 4.43 GV

2010 2012 2012 2013 2014 2016 2016 2017 0.14 0.16

c) 3.64 < R < 4.02 GV

2010 2012 2012 2013 2014 2016 2016 2017 0.14 0.16 0.16 0.18 a) 2.15 < R < 2.40 GV

He

4

Φ /

He

3

Φ

0.12 0.18 0.14 0.18

b) 2.97 < R < 3.29 GV

F.Giovacchini 9

4He and 3He

Fluxes and ratio vs time in 21 periods of 4 Bartels rotations each (108 days)

Above 4GV the ratio vs R is time independent

Submitted to PRL refer to upcoming AMS publication Submitted to PRL refer to upcoming AMS publication

3He and 4He and ratio time variation

ti = February 28±42, 2015

Data: 6.5 y (05/2011 to 11/2017)

2011 2012 2013 2014 2015 2016 2017 2018 1.4 1.5 1.6 1.7 0.14 0.15 0.16 0.17

e) 14.10 < R < 15.30 GV

2010 2012 2012 2013 2014 2016 2016 2017 20 30 2 3 4 5

d) 4.02 < R < 4.43 GV

2010 2012 2012 2013 2014 2016 2016 2017 10 20 30 40 2 4 6

c) 3.64 < R < 4.02 GV

2010 2012 2012 2013 2014 2016 2016 2017 20 40 60 5 50 100 5 10 15 20

a) 2.15 < R < 2.40 GV

]

  • 1

sr s GV)

2

[(m

He

4

Φ ]

  • 1

sr s GV)

2

[(m

He

3

Φ

b) 2.97 < R < 3.29 GV

10 10

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SLIDE 10

2 3 4 5 6 7 8 9 10 20

R [GV]

2

10

3

10

]

  • 1

)

  • 1.7

sr s GV

2

[(m

2.7

R × Φ

He

4

He

3

F.Giovacchini 10

Data: 6.5 years (May 2011 to Nov 2017) 100 million 4He : 2.1-21 GV 18 million 3He : 1.9-15 GV

Submitted to PRL refer to upcoming AMS publication

Helium Isotopes Flux vs R

TAUP2019, Toyama

The shaded regions show the range of time variation AMS time-averaged 3He and 4He Fluxes as function of rigidity with total error

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SLIDE 11

F.Giovacchini 11

No previous measurement

  • f the 3He/4He ratio vs R.

Above 4GV the ratio has a rigidity dependence well described by a single power law

Submitted to PRL refer to upcoming AMS publication

Helium Isotopes ratio vs R

TAUP2019, Toyama

AMS time-everaged 3He/4He as function of rigidity with total error

Δ=-0.294 ± 0.004

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SLIDE 12

12

TOF NaF AGL

  • Mass templates reconstructed from the β resolution and

R resolution models obtained from MC simulation.

Lithium Isotopes identification with AMS02

F.Giovacchini TAUP2019, Toyama

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SLIDE 13

13

  • First measurement of 6Li and 7Li

fluxes above 0.3 GeV/n.

Lithium Isotopes Fluxes vs Ekin

Preliminary data, refer to upcoming AMS PRL publication Preliminary data, refer to upcoming AMS PRL publication F.Giovacchini TAUP2019, Toyama

Data Set: 6.5 years (May 2011 to Nov 2017)

Preliminary data, refer to upcoming AMS PRL publication

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SLIDE 14

14

Preliminary data, refer to upcoming AMS PRL publication

Lithium Isotopes ratio vs Ekin

F.Giovacchini TAUP2019, Toyama

  • First measurement of 6Li /7Li flux ratio above 1 GeV/n.
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SLIDE 15

15

Prospect: Beryllium Isotopes

F.Giovacchini TAUP2019, Toyama

  • Being Beryllium isotopes pure secondary CRs, the ratio 10Be/9Be (where 10Be unstable) can be

used to estimate the CRs lifetime

  • Experimentally challenging, lack of measurements
  • AMS collected over 1 million Beryllium events
  • At the limit of the resolution but promising

1 −

10 1 10

Ekn [GeV/n]

0.05 0.1 0.15 0.2

Be Be/

10

CRDB (http://lpsc.in2p3.fr/crdb) Balloon(1973/08) Balloon(1977/05) Balloon(1977/09) ISEE3-HKH(1978/08-1979/08)

AGL, Ekin [4.44,4.91] GeV/n

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SLIDE 16

Ø Isotopic composition of light nuclei in cosmic rays is a key measurement to understand cosmic rays origin and propagation. Ø AMS is publishing a precision measurement of the CRs 3He and 4He isotopes fluxes and their ratio with rigidity from 1.9 GV to 15 GV for 3He, from 2.1 GV to 21 GV for 4He and from 2.1 to 15 for 3He/4He. Ø Above 4GV the 3He/4He flux ratio was found to be time independent and its rigidity dependence is well described by a single power law a RΔ with Δ=-0.295+-0.004. Ø AMS will extend the measurement of light isotopes, D, 6Li and 7Li toward unexplored energy range never achieved by other experiment with unprecedented precision: First measurement of D flux above 1 GeV/n and of 6Li and 7Li fluxes above 0.3 GeV/n. Ø Work ongoing to analyze heavier isotopes like Be.

Conclusions

F.Giovacchini 16 TAUP2019, Toyama

∝

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SLIDE 17

Tiank you!

Credits to my daughters, Arianna & Cecilia

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SLIDE 18

(GeV/n)

n

K 1 10 M/M ∆ 0.1 0.15 0.2 0.25 0.3 0.35 0.4

ΔM/M Mass Resolution for Z=1

18

TOF NaF Aerogel

18

∆M M = ✓∆p p ◆ ⊕ 1 (1 − β2) ✓∆β β ◆

Tracker, Δp/p ≈ 10% up to 20 GV Aerogel: Δβ/β ≈ 0.1%, β>0.96 ToF, Δβ/β2 ≈ 4%

NaF: Δβ/β ≈ 0.4%, β>0.75

F.Giovacchini TAUP2019, Toyama

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SLIDE 19

4He Fragmentation Cr

He Fragmentation Cross Sections

  • ss Sections
  • 3He and 3H production cross sections in 4He interactions are expected to be similar

and constant above ~0.2 GeV/n 3He contamination from 4He→3He Fragmentation

The 4He → 3He fragmentation is determined from the 4He → 3H direct measurement within AMS

7

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SLIDE 20

AMS: Identification of isotopes

20

  • F. Dimiccoli -- TIFPA
  • > Template fit of mass distributions

D mass resolution

F.Giovacchini TAUP2019, Toyama

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SLIDE 21

F.Giovacchini

0.7 1 2 3 4 5

]

2

Mass [GeV/c

10000 20000 30000

Events

Data Simulation

p H

2

H

3

21

Z>2 fragmentations into He is negligible and removed with L1 charge. The knowledge of the contamination in the 3He sample from 4He interaction is the most relevant sys.

4He -> 3He fragmentation cross section is determined from 4He -> 3H, used as proxy process

since it can be directly measured within AMS.

3He and 3H production cross section in 4He

interactions are expected to be similar and constant above ~0.2 GeV/n L1, Z=2 L2-L8, Z=1 TRD, Z=2

3He from 4He fragmentation

TAUP2019, Toyama

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SLIDE 22

Properties of Cosmic Helium

Proton and helium fluxes as function of time.

22

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SLIDE 23

F.Giovacchini 23

The spectral index of 3He/4He rigidity dependence extrapolated to highest energies is in good agreement with the B/O (and B/C) one.

∝

Submitted to PRL refer to upcoming AMS publication

Helium Isotopes: Results

TAUP2019, Toyama

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SLIDE 24

24 Preliminary data, refer to upcoming AMS PRL publication

Lithium Isotopes with AMS02

Preliminary data, refer to upcoming AMS PRL publication

  • 6Li/7Li ratio vs rigidity

F.Giovacchini TAUP2019, Toyama