Top$of$Instrument$Correction$for$Cosmic$Ray$Nuclei$with$AMS;02

Natalie$FerrisMIT,$Dickinson$College

International$School$for$Subnuclear$Physics,$Erice 2017

When$ADONE$was$constructed$in$the$mid$1960s$it$was$the$highest$energy$e+$e; collider.$

Zichichi began$a$comprehensive$study$of$all$of$the$final$states$of$e+$e; collisions$with$a$large$solid$angle$detector.

AMS$is$the$largest$acceptance$precision$spectrometer$of$its$kindto$study$cosmic$rays$with$unprecedented$precision. 2

AMS$Collaboration

AMS$is$an$international$collaboration$with$16$countries

USAMIT - CAMBRIDGENASA GODDARD SPACE FLIGHT CENTERNASA JOHNSON SPACE CENTERUNIV. OF HAWAII UNIV. OF MARYLAND - DEPT OF PHYSICSYALE UNIVERSITY - NEW HAVEN

MEXICOUNAM

FINLANDUNIV. OF TURKU

FRANCELUPM MONTPELLIERLAPP ANNECYLPSC GRENOBLE

GERMANYRWTH-I.

KIT - KARLSRUHE

ITALYASIIROE FLORENCEINFN & UNIV. OF BOLOGNAINFN & UNIV. OF MILANO-BICOCCAINFN & UNIV. OF PERUGIAINFN & UNIV. OF PISAINFN & UNIV. OF ROMAINFN & UNIV. OF TRENTO

NETHERLANDSESA-ESTECNIKHEF

RUSSIAITEPKURCHATOV INST.

SPAINCIEMAT - MADRIDI.A.C. CANARIAS.

SWITZERLANDETH-ZURICHUNIV. OF GENEVA

CHINACALT (Beijing)IEE (Beijing)IHEP (Beijing)NLAA (Beijing)SJTU (Shanghai)SEU (Nanjing)SYSU (Guangzhou)SDU (Jinan)

KOREAEWHA

KYUNGPOOK NAT.UNIV.

PORTUGALLAB. OF INSTRUM. LISBON

TAIWAN

TURKEYMETU, ANKARA

BRASILIFSC$– SÃO$CARLOS$INSTITUTE$OF$PHYSICS

ACAD. SINICA (Taipei)CSIST (Taipei)

NCU (Chung Li)NCKU (Tainan)

3

The$Alpha$Magnetic$Spectrometer

Tracker

1

2

7$8

3$4

9

5$6

TRDIdentify,e+,,e/

Silicon,TrackerZ,,P

ECALE,of,e+,,e/

RICHZ,,E

TOFZ,,EParticles$and$nuclei$are$defined$

by$their$charge$(Z)$and$energy$(E!~ P)

Z"and E!~!Pare"measured"independently"by"""Tracker,"RICH,"TOF""and"ECAL

Magnet�Z

4

Light$Nuclei$Analysis

Inner$Tracker$2G8

Tracker

1

2

7$8

3$4

9

5$6

Tracker$Plane$1

Tracker$Plane$9

Upper TOF

Lower$TOF

0.30

0.12

0.30

0.16

0.16

Charge$Resolution$(Z=6)$

5

Momentum/Charge [GV]10 210 310

B/C

0.030.040.050.06

0.1

0.2

0.30.4Physics$Result:$The$Boron;to;Carbon$(B/C)$flux$ratio

M.9Aguilar9et#al.,9Phys.9Rev.9Lett.9117,,2311019(2016)

11$million$nuclei

7

AMS

Primary$Cosmic$Rays$(p,$He,$C,$O,$…)

Primary$cosmic$rays$carry$information$about$their$source$and$propagation.

C,$O,$…,$Fe +$ISM$! Li,$Be,$B$+$X

AMS

Secondary$Cosmic$Rays$(Li,$Be,$B,$…)

Secondary$cosmic$rays$carry$information$about$propagation$of$primaries,secondaries$and$the$ISM.

ISM

7

[GeV/n]KE1 10 210 310

B/C

0.02

0.030.040.05

0.1

0.2

0.30.4

C2/HEAO3Webber et al.CRN/Spacelab2AMS01ATIC02CREAM-ITRACERPAMELAAMS02

B/C$Comparison$with$Other$Experiments

Phys.$Rev.$Lett.$117,$231102$(2016)

9

CowsikAPJ$786$(2014)$

Momentum/Charge [GV]10 210 310

B/C

0.030.040.050.06

0.1

0.2

0.30.4Physics$Result:$The$Boron;to;Carbon$(B/C)$flux$ratio

11$million$nuclei

M.9Aguilar9et#al.,9Phys.9Rev.9Lett.9117,,2311019(2016) 9

Rigidity [GV]10 210 310

/ (B

/C)

B/C

σ

0

0.1

0.2

0.3

0.4

B/C$Errors

Rigidity Scale

Background

UnfoldingAcceptance

Statistics

Total

Dominating$above$100GV

11

Top;of;the;Instrument$corrections

Two$contributions:

A)Interactions$of$higher$charge$nuclei$between$L1$and$L2$can$lead$to$contamination$of$our$sample$due$to$the$finite$charge$resolution$of$L1G>$this$can$be$determined$with$data

B)Higher$charge$nuclei$interacting$above$L1$can$pass$all$our$selection$and$produce$a$contamination$of$the$selected$sample;>$determine$from$Monte$Carlo

Carbon

Boron

L5/L6

L3/L4

L2

L7/L8

L9

L1

11

A)

A)$$C$to$B$event

Date:$2014;167.12:29:19 13

Carbon

Boron$(11GV)

Tracker$L1$=$5.9

Tracker$L2;L8$=$4.9

Lower$TOF$=$5.0

Upper$TOF$1$=$5.8

Upper$TOF$2$=$10.9

L1

L2L3GL4L5GL6L7GL8

L9

Charge:

A)$Background$from$Interactions$between$L1$and$inner$tracker$

• Minor$background$in$boron$sample$from$charge$determination$uncertainty$in$Tracker$L1

• With$efficient$charge$cut$on$L1$(# > %&%)$the$residual$background$less$than$3%$over$the$entire$rigidity$range.$

Tracker L1 charge distributionfor boron selections in the innertracker

M.9Aguilar9et#al.,9Phys.9Rev.9Lett.9117,,2311019(2016)13

Rigidity$Bin:$9$– 11$GV

Top;of;the;Instrument$corrections

Two$contributions:

A)Interactions$of$higher$charge$nuclei$between$L1$and$L2$can$lead$to$contamination$of$our$sample$due$to$the$finite$charge$resolution$of$L1;>$this$can$be$determined$with$data

B)Higher$charge$nuclei$interacting$above$L1$can$pass$all$our$selection$and$produce$a$contamination$of$the$selected$sampleG>$determine$from$Monte$Carlo

Carbon

L5/L6

L3/L4

L2

L7/L8

L9

Boron

L1

14

B)

B)$Background$from$Interactions$above$tracker$L1

Due$to$their$abundance$in$cosmic$rays$only$nuclei$up$to$Oxygen$contribute$significantly.

Need$to$rely$on$MC$to$determine$this$background,$but…

1.$We$have$tuned$MC$to$reproduce$the$overall$inelastic$interaction$rate$we$see$in$data$(see$X.$Qin$talk)

2.$We$can$check$individual$fragmentation$channels$between$data$and$MC

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B)$Fragmentation$Correction$from$above$L1

C! B

N$! B

O$! B

Total$Contamination

Rigidity$(GV)

Contam

ination

Raw MC$correction$for$Boron

16

B)$Individual$Fragmentation$Channel$Corrections

Inner$tracker$charge$distribution$for$a$carbon$selection$in$L1$for$two$different$rigidity$bins.

Rigidity$Bins:$a)$27G36$GV,$b)$192G525$GV

Carbon$to$Boron$Channel

17

B)$Top;of;Instrument$Fragmentation

C! B

N$! B

O$! B

Total$Contamination

Rigidity$(GV)

Contam

ination

The$contamination$to$the$boron$flux$is$less$than$6%$with$a$systematic$uncertainty$of$<$0.5%

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Withincreasingsta-s-csthrough2024,wewillmeasuretheelementsuptoironandbeyond.

AnalyzedandtobeReanalyzed

BeingAnalyzed Accessibleby2024

Nuclei$measurements$with$AMS

Analyzed

19

Boron

20

Preliminary$ResultsPlease$refer$to$the$upcoming$publication$in$PRL

2.9$million$nuclei5 years

Summary

• The high acceptance and long duration of AMS results in smallstatistical error.

• To match our statistical precision, we need to perform in depthanalysis of the sources of systematic errors.

• The redundancy in charge measurements with AMS allows us tocheck inelastic interactions and select high purity nuclei samples.

• Analysis for fragmentation between L1 and the inner tracker can beperformed using data, while interactions occurring above L1 must bedetermined with MC and corrected with data.

• This correction is important as it allows for precise analysis of nucleiup to iron and beyond.

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Flux$measurement

Φ j =N j

Tjε jAjΔRj

Measurement$in$rigidity$bins$(Rj,$Rj+ΔRj)

Exposure$time$Tj

Trigger$efficiency$εj

Aj:$Effective$acceptance

Nj:$Number$of$events$without$background$and$corrected$with$the$resolution$function

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