SlideShare a Scribd company logo
1 of 2
Download to read offline
The Geiger Counter
                                 Colin Hannesse and Frédéric Jacobs
                     With contributions from : Chloé Rousselle and Alexandre Jolly
                     With special thanks to : Loïc van Oldeneel and Luigi Siragusa


1     Physics notions
1.1    Radioactivity
                                       Radioactivity is a physical natural phenomenon in which an
                                       unstable nuclei is decaying by ejecting energy in different
                                       ways:
                                           • The Alpha ray (α)is the emission of an helium nucleus (2
                                             protons, 2 neutrons), mostly observed for heavy nuclei.
                                           • The Beta ray (β) is the emission of an electron or a
                                             positron.
                                           • The Gamma ray (γ) is observed in the two cases above.
                                             It is an electromagnetic wave (same nature as light).

                                       1.2    Isotopes
                                       Two atoms are called isotopes if they have both the same
                                       number of protons and a different number of neutrons.
                                       Example : The carbon-14, written 14C, is the isotope of the
                                                                          6
                                       carbon-12 (the carbon that is mostly found at the natural
                                       state, written 12C).
                                                       6


1.3    Irradiation and Contamination
    • An object is irradiated when it is hit by a ionizing ray. It doesn’t make it radioactive.
    • An object is contaminated when there are radioactive elements on it. The result is that the
      whole is radioactive (object + radioactive dust).

 Dosis in Sv (Sieverts)   Symptoms
           0,1            Treshold below which one never has found any effect of radiation on health.
           0,2            Threshold below we do not observe any symptoms..
           0,3            Small abnormalities on blood samples (less lymphocytes).
            1             First clinical symptoms (nausea, vomiting).
            2             Hospitalization necessary: bone marrow is affected (anemia, infections, bleeding).
            3             First signs on the skin(redness), hair loss.
           4,5            Lethal dose (50% mortality if untreated).
            8             Bowel are reached (diarrhea) and respiratory functions too.
                          Death follows after several days or weeks.
           10             Neurological symptoms (coma) followed by death in several days or weeks.

Sievert is a scale that marks the biological impact due to radiations.


                                                  1
2    The Electronic Components
The electronics of the Geiger counter is made out of 3 main parts. The transformer, the Geiger
tube and the signal stretcher.
                                                                 After having passed in the chop-
                                                             per, the current coming from the bat-
                                                             tery is transformed into alternating
                                                             current. Then, the transformer am-
                                                             plifies the voltage up to 400 Volts
                                                             that is needed by the Geiger tube
                                                             to work. This high voltage on the
                                                             electrodes allows the current passing
                                                             through the tube when a particle en-
                                                             ters the tube. This event lasts only
                                                             a few microseconds. If the signal was
                                                             directly converted to a flashlight or
                                                             sound, it would be to short to be seen
                                                             or heard. For that specific reason, we
                                                             added a signal stretcher that allows
                                                             the signal to be long enough to be
                                                             seen. Given that this is an digital cir-
                                                             cuit, this means the output is either
on or off and its state doesn’t depend on the intensity and speed of the particles.

The Geiger tube is made of a metallic tube filled with ionizable gas in which are placed two
electrodes.




    Above are represented the two different cases viewed from inside the Geiger tube.
    • When no particle enters the tube, no current can pass through the tube because the gas is
      not naturally conductive.
    • When a particle enters the tube, it is likely to grab electrons from the gas. This is called
      ionization and now the gas is conductive during a short moment. Therefore the current can
      pass through it.


                                                 2

More Related Content

What's hot

PEPTIDE LABELLING & GAMMA RAY SPECTROSCOPY
PEPTIDE LABELLING & GAMMA RAY SPECTROSCOPYPEPTIDE LABELLING & GAMMA RAY SPECTROSCOPY
PEPTIDE LABELLING & GAMMA RAY SPECTROSCOPYupvita pandey
 
Chemical and Physical Properties: Radioactivity & Radioisotopes
Chemical and Physical Properties: Radioactivity & Radioisotopes Chemical and Physical Properties: Radioactivity & Radioisotopes
Chemical and Physical Properties: Radioactivity & Radioisotopes ulcerd
 
Radioactive decay, kinetics and equilibrium
Radioactive decay, kinetics and equilibriumRadioactive decay, kinetics and equilibrium
Radioactive decay, kinetics and equilibriumBiji Saro
 
Radioactivity: physics form 5.
Radioactivity: physics form 5.Radioactivity: physics form 5.
Radioactivity: physics form 5.Ramli Rem
 
Chapter 2 properties of radiations and radioisotopes
Chapter 2 properties of radiations and radioisotopesChapter 2 properties of radiations and radioisotopes
Chapter 2 properties of radiations and radioisotopesROBERT ESHUN
 
History of Quantum Mechanics
History of Quantum MechanicsHistory of Quantum Mechanics
History of Quantum MechanicsChad Orzel
 
A comparative study of the scintillation detector na i(tl) in two sizes
A comparative study of the scintillation detector na i(tl) in two sizesA comparative study of the scintillation detector na i(tl) in two sizes
A comparative study of the scintillation detector na i(tl) in two sizesAlexander Decker
 
Discovery of radioactivity
Discovery of   radioactivityDiscovery of   radioactivity
Discovery of radioactivityyash8894
 
Dual nature of matter and radiations
Dual nature of matter and radiationsDual nature of matter and radiations
Dual nature of matter and radiationsSelf-employed
 
Direct sensing
Direct sensingDirect sensing
Direct sensingshravan900
 
Gamma Ray Spectroscopy Report
Gamma Ray Spectroscopy ReportGamma Ray Spectroscopy Report
Gamma Ray Spectroscopy Reportpixiejen
 
PHOTODETECTORS
PHOTODETECTORSPHOTODETECTORS
PHOTODETECTORSAakankshaR
 

What's hot (19)

PEPTIDE LABELLING & GAMMA RAY SPECTROSCOPY
PEPTIDE LABELLING & GAMMA RAY SPECTROSCOPYPEPTIDE LABELLING & GAMMA RAY SPECTROSCOPY
PEPTIDE LABELLING & GAMMA RAY SPECTROSCOPY
 
Radioactivity
RadioactivityRadioactivity
Radioactivity
 
Chemical and Physical Properties: Radioactivity & Radioisotopes
Chemical and Physical Properties: Radioactivity & Radioisotopes Chemical and Physical Properties: Radioactivity & Radioisotopes
Chemical and Physical Properties: Radioactivity & Radioisotopes
 
Radioactive decay, kinetics and equilibrium
Radioactive decay, kinetics and equilibriumRadioactive decay, kinetics and equilibrium
Radioactive decay, kinetics and equilibrium
 
Radioactivity: physics form 5.
Radioactivity: physics form 5.Radioactivity: physics form 5.
Radioactivity: physics form 5.
 
Radioactivity
RadioactivityRadioactivity
Radioactivity
 
Chapter 2 properties of radiations and radioisotopes
Chapter 2 properties of radiations and radioisotopesChapter 2 properties of radiations and radioisotopes
Chapter 2 properties of radiations and radioisotopes
 
History of Quantum Mechanics
History of Quantum MechanicsHistory of Quantum Mechanics
History of Quantum Mechanics
 
A comparative study of the scintillation detector na i(tl) in two sizes
A comparative study of the scintillation detector na i(tl) in two sizesA comparative study of the scintillation detector na i(tl) in two sizes
A comparative study of the scintillation detector na i(tl) in two sizes
 
Discovery of radioactivity
Discovery of   radioactivityDiscovery of   radioactivity
Discovery of radioactivity
 
Radioactive decay
Radioactive decayRadioactive decay
Radioactive decay
 
Dual nature of matter and radiations
Dual nature of matter and radiationsDual nature of matter and radiations
Dual nature of matter and radiations
 
Lecture 25.1- Radiation
Lecture 25.1- RadiationLecture 25.1- Radiation
Lecture 25.1- Radiation
 
Direct sensing
Direct sensingDirect sensing
Direct sensing
 
A2 Direct Sensing
A2 Direct SensingA2 Direct Sensing
A2 Direct Sensing
 
Gamma Ray Spectroscopy Report
Gamma Ray Spectroscopy ReportGamma Ray Spectroscopy Report
Gamma Ray Spectroscopy Report
 
Radio isotope
Radio isotopeRadio isotope
Radio isotope
 
Radioactivity
RadioactivityRadioactivity
Radioactivity
 
PHOTODETECTORS
PHOTODETECTORSPHOTODETECTORS
PHOTODETECTORS
 

Viewers also liked

10 16-11 service
10 16-11 service10 16-11 service
10 16-11 servicehirdab
 
10 02-11 service
10 02-11 service10 02-11 service
10 02-11 servicehirdab
 
09 25-11 service
09 25-11 service09 25-11 service
09 25-11 servicehirdab
 
04 10-11 service
04 10-11 service04 10-11 service
04 10-11 servicehirdab
 
11 13-11 service
11 13-11 service11 13-11 service
11 13-11 servicehirdab
 
10 06-13 service
10 06-13 service10 06-13 service
10 06-13 servicehirdab
 
09 29-13 service
09 29-13 service09 29-13 service
09 29-13 servicehirdab
 
10 23-11 service
10 23-11 service10 23-11 service
10 23-11 servicehirdab
 

Viewers also liked (8)

10 16-11 service
10 16-11 service10 16-11 service
10 16-11 service
 
10 02-11 service
10 02-11 service10 02-11 service
10 02-11 service
 
09 25-11 service
09 25-11 service09 25-11 service
09 25-11 service
 
04 10-11 service
04 10-11 service04 10-11 service
04 10-11 service
 
11 13-11 service
11 13-11 service11 13-11 service
11 13-11 service
 
10 06-13 service
10 06-13 service10 06-13 service
10 06-13 service
 
09 29-13 service
09 29-13 service09 29-13 service
09 29-13 service
 
10 23-11 service
10 23-11 service10 23-11 service
10 23-11 service
 

Similar to Building a Geiger Counter for iPhone

Radioactive Isotopes, 27 April, 20.pdf
Radioactive Isotopes, 27 April, 20.pdfRadioactive Isotopes, 27 April, 20.pdf
Radioactive Isotopes, 27 April, 20.pdfSonuSiddique2
 
Radiation Interactions.pptx
Radiation Interactions.pptxRadiation Interactions.pptx
Radiation Interactions.pptxMunir Ahmad
 
History of Quantum Mechanics
History of Quantum MechanicsHistory of Quantum Mechanics
History of Quantum MechanicsChad Orzel
 
Chap1 physics and chemistry of radiation absorption
Chap1 physics and chemistry of radiation absorptionChap1 physics and chemistry of radiation absorption
Chap1 physics and chemistry of radiation absorptionKorea Cancer Center Hospital
 
Radiation Detection Principles.pptx
Radiation Detection Principles.pptxRadiation Detection Principles.pptx
Radiation Detection Principles.pptxMunir Ahmad
 
Radiopharmaceuticals (PCI syllabus, B.Pharm)
Radiopharmaceuticals (PCI syllabus, B.Pharm)Radiopharmaceuticals (PCI syllabus, B.Pharm)
Radiopharmaceuticals (PCI syllabus, B.Pharm)Dr. Alex Martin
 
THERMIONIC EMMISION AND RADIOACTIVITY
THERMIONIC EMMISION AND RADIOACTIVITYTHERMIONIC EMMISION AND RADIOACTIVITY
THERMIONIC EMMISION AND RADIOACTIVITYHimanshu Singh
 
Chapter 21 Lecture- Nuclear Chemistry
Chapter 21 Lecture- Nuclear ChemistryChapter 21 Lecture- Nuclear Chemistry
Chapter 21 Lecture- Nuclear ChemistryMary Beth Smith
 
All document for BIO-II course.pptx
All document for BIO-II course.pptxAll document for BIO-II course.pptx
All document for BIO-II course.pptxTirusew1
 
Chapter 12 –Radioactivity.pptx
Chapter 12 –Radioactivity.pptxChapter 12 –Radioactivity.pptx
Chapter 12 –Radioactivity.pptxYashhGoel
 
Radiopharmaceuticals
RadiopharmaceuticalsRadiopharmaceuticals
RadiopharmaceuticalsSONALI GADGE
 
Radioactivity
RadioactivityRadioactivity
RadioactivityE H Annex
 
Geiger muller counter
Geiger muller counter Geiger muller counter
Geiger muller counter ARCHITBHARTI
 
C18-Radioactivity_and_Nuclear_Reactions.ppt
C18-Radioactivity_and_Nuclear_Reactions.pptC18-Radioactivity_and_Nuclear_Reactions.ppt
C18-Radioactivity_and_Nuclear_Reactions.pptJezrylleBalaong
 

Similar to Building a Geiger Counter for iPhone (20)

Radioactive Isotopes, 27 April, 20.pdf
Radioactive Isotopes, 27 April, 20.pdfRadioactive Isotopes, 27 April, 20.pdf
Radioactive Isotopes, 27 April, 20.pdf
 
Radiation Interactions.pptx
Radiation Interactions.pptxRadiation Interactions.pptx
Radiation Interactions.pptx
 
Radiation detectors
Radiation detectorsRadiation detectors
Radiation detectors
 
History of Quantum Mechanics
History of Quantum MechanicsHistory of Quantum Mechanics
History of Quantum Mechanics
 
Chap1 physics and chemistry of radiation absorption
Chap1 physics and chemistry of radiation absorptionChap1 physics and chemistry of radiation absorption
Chap1 physics and chemistry of radiation absorption
 
Radiation Detection Principles.pptx
Radiation Detection Principles.pptxRadiation Detection Principles.pptx
Radiation Detection Principles.pptx
 
Radiopharmaceuticals (PCI syllabus, B.Pharm)
Radiopharmaceuticals (PCI syllabus, B.Pharm)Radiopharmaceuticals (PCI syllabus, B.Pharm)
Radiopharmaceuticals (PCI syllabus, B.Pharm)
 
THERMIONIC EMMISION AND RADIOACTIVITY
THERMIONIC EMMISION AND RADIOACTIVITYTHERMIONIC EMMISION AND RADIOACTIVITY
THERMIONIC EMMISION AND RADIOACTIVITY
 
IR Spectroscopy.pdf
IR Spectroscopy.pdfIR Spectroscopy.pdf
IR Spectroscopy.pdf
 
IR spectroscopy
IR spectroscopyIR spectroscopy
IR spectroscopy
 
Nuclear medicine
Nuclear medicineNuclear medicine
Nuclear medicine
 
Em radiation x
Em radiation xEm radiation x
Em radiation x
 
Chapter 21 Lecture- Nuclear Chemistry
Chapter 21 Lecture- Nuclear ChemistryChapter 21 Lecture- Nuclear Chemistry
Chapter 21 Lecture- Nuclear Chemistry
 
All document for BIO-II course.pptx
All document for BIO-II course.pptxAll document for BIO-II course.pptx
All document for BIO-II course.pptx
 
Chapter 12 –Radioactivity.pptx
Chapter 12 –Radioactivity.pptxChapter 12 –Radioactivity.pptx
Chapter 12 –Radioactivity.pptx
 
Radiopharmaceuticals
RadiopharmaceuticalsRadiopharmaceuticals
Radiopharmaceuticals
 
Radioactivity
RadioactivityRadioactivity
Radioactivity
 
Geiger muller counter
Geiger muller counter Geiger muller counter
Geiger muller counter
 
C18-Radioactivity_and_Nuclear_Reactions.ppt
C18-Radioactivity_and_Nuclear_Reactions.pptC18-Radioactivity_and_Nuclear_Reactions.ppt
C18-Radioactivity_and_Nuclear_Reactions.ppt
 
Radioactivity.pptx
Radioactivity.pptxRadioactivity.pptx
Radioactivity.pptx
 

Recently uploaded

الأمن السيبراني - ما لا يسع للمستخدم جهله
الأمن السيبراني - ما لا يسع للمستخدم جهلهالأمن السيبراني - ما لا يسع للمستخدم جهله
الأمن السيبراني - ما لا يسع للمستخدم جهلهMohamed Sweelam
 
ERP Contender Series: Acumatica vs. Sage Intacct
ERP Contender Series: Acumatica vs. Sage IntacctERP Contender Series: Acumatica vs. Sage Intacct
ERP Contender Series: Acumatica vs. Sage IntacctBrainSell Technologies
 
How to Check CNIC Information Online with Pakdata cf
How to Check CNIC Information Online with Pakdata cfHow to Check CNIC Information Online with Pakdata cf
How to Check CNIC Information Online with Pakdata cfdanishmna97
 
Microsoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - QuestionnaireMicrosoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - QuestionnaireExakis Nelite
 
Intro to Passkeys and the State of Passwordless.pptx
Intro to Passkeys and the State of Passwordless.pptxIntro to Passkeys and the State of Passwordless.pptx
Intro to Passkeys and the State of Passwordless.pptxFIDO Alliance
 
AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)
AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)
AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)Samir Dash
 
Easier, Faster, and More Powerful – Notes Document Properties Reimagined
Easier, Faster, and More Powerful – Notes Document Properties ReimaginedEasier, Faster, and More Powerful – Notes Document Properties Reimagined
Easier, Faster, and More Powerful – Notes Document Properties Reimaginedpanagenda
 
ADP Passwordless Journey Case Study.pptx
ADP Passwordless Journey Case Study.pptxADP Passwordless Journey Case Study.pptx
ADP Passwordless Journey Case Study.pptxFIDO Alliance
 
State of the Smart Building Startup Landscape 2024!
State of the Smart Building Startup Landscape 2024!State of the Smart Building Startup Landscape 2024!
State of the Smart Building Startup Landscape 2024!Memoori
 
AI mind or machine power point presentation
AI mind or machine power point presentationAI mind or machine power point presentation
AI mind or machine power point presentationyogeshlabana357357
 
Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...
Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...
Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...ScyllaDB
 
Vector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptxVector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptxjbellis
 
JohnPollard-hybrid-app-RailsConf2024.pptx
JohnPollard-hybrid-app-RailsConf2024.pptxJohnPollard-hybrid-app-RailsConf2024.pptx
JohnPollard-hybrid-app-RailsConf2024.pptxJohnPollard37
 
Design and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data ScienceDesign and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data SciencePaolo Missier
 
AI in Action: Real World Use Cases by Anitaraj
AI in Action: Real World Use Cases by AnitarajAI in Action: Real World Use Cases by Anitaraj
AI in Action: Real World Use Cases by AnitarajAnitaRaj43
 
Google I/O Extended 2024 Warsaw
Google I/O Extended 2024 WarsawGoogle I/O Extended 2024 Warsaw
Google I/O Extended 2024 WarsawGDSC PJATK
 
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)Paige Cruz
 
“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf
“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf
“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdfMuhammad Subhan
 
Top 10 CodeIgniter Development Companies
Top 10 CodeIgniter Development CompaniesTop 10 CodeIgniter Development Companies
Top 10 CodeIgniter Development CompaniesTopCSSGallery
 
TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...
TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...
TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...TrustArc
 

Recently uploaded (20)

الأمن السيبراني - ما لا يسع للمستخدم جهله
الأمن السيبراني - ما لا يسع للمستخدم جهلهالأمن السيبراني - ما لا يسع للمستخدم جهله
الأمن السيبراني - ما لا يسع للمستخدم جهله
 
ERP Contender Series: Acumatica vs. Sage Intacct
ERP Contender Series: Acumatica vs. Sage IntacctERP Contender Series: Acumatica vs. Sage Intacct
ERP Contender Series: Acumatica vs. Sage Intacct
 
How to Check CNIC Information Online with Pakdata cf
How to Check CNIC Information Online with Pakdata cfHow to Check CNIC Information Online with Pakdata cf
How to Check CNIC Information Online with Pakdata cf
 
Microsoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - QuestionnaireMicrosoft CSP Briefing Pre-Engagement - Questionnaire
Microsoft CSP Briefing Pre-Engagement - Questionnaire
 
Intro to Passkeys and the State of Passwordless.pptx
Intro to Passkeys and the State of Passwordless.pptxIntro to Passkeys and the State of Passwordless.pptx
Intro to Passkeys and the State of Passwordless.pptx
 
AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)
AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)
AI+A11Y 11MAY2024 HYDERBAD GAAD 2024 - HelloA11Y (11 May 2024)
 
Easier, Faster, and More Powerful – Notes Document Properties Reimagined
Easier, Faster, and More Powerful – Notes Document Properties ReimaginedEasier, Faster, and More Powerful – Notes Document Properties Reimagined
Easier, Faster, and More Powerful – Notes Document Properties Reimagined
 
ADP Passwordless Journey Case Study.pptx
ADP Passwordless Journey Case Study.pptxADP Passwordless Journey Case Study.pptx
ADP Passwordless Journey Case Study.pptx
 
State of the Smart Building Startup Landscape 2024!
State of the Smart Building Startup Landscape 2024!State of the Smart Building Startup Landscape 2024!
State of the Smart Building Startup Landscape 2024!
 
AI mind or machine power point presentation
AI mind or machine power point presentationAI mind or machine power point presentation
AI mind or machine power point presentation
 
Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...
Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...
Event-Driven Architecture Masterclass: Integrating Distributed Data Stores Ac...
 
Vector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptxVector Search @ sw2con for slideshare.pptx
Vector Search @ sw2con for slideshare.pptx
 
JohnPollard-hybrid-app-RailsConf2024.pptx
JohnPollard-hybrid-app-RailsConf2024.pptxJohnPollard-hybrid-app-RailsConf2024.pptx
JohnPollard-hybrid-app-RailsConf2024.pptx
 
Design and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data ScienceDesign and Development of a Provenance Capture Platform for Data Science
Design and Development of a Provenance Capture Platform for Data Science
 
AI in Action: Real World Use Cases by Anitaraj
AI in Action: Real World Use Cases by AnitarajAI in Action: Real World Use Cases by Anitaraj
AI in Action: Real World Use Cases by Anitaraj
 
Google I/O Extended 2024 Warsaw
Google I/O Extended 2024 WarsawGoogle I/O Extended 2024 Warsaw
Google I/O Extended 2024 Warsaw
 
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
Observability Concepts EVERY Developer Should Know (DevOpsDays Seattle)
 
“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf
“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf
“Iamnobody89757” Understanding the Mysterious of Digital Identity.pdf
 
Top 10 CodeIgniter Development Companies
Top 10 CodeIgniter Development CompaniesTop 10 CodeIgniter Development Companies
Top 10 CodeIgniter Development Companies
 
TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...
TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...
TrustArc Webinar - Unified Trust Center for Privacy, Security, Compliance, an...
 

Building a Geiger Counter for iPhone

  • 1. The Geiger Counter Colin Hannesse and Frédéric Jacobs With contributions from : Chloé Rousselle and Alexandre Jolly With special thanks to : Loïc van Oldeneel and Luigi Siragusa 1 Physics notions 1.1 Radioactivity Radioactivity is a physical natural phenomenon in which an unstable nuclei is decaying by ejecting energy in different ways: • The Alpha ray (α)is the emission of an helium nucleus (2 protons, 2 neutrons), mostly observed for heavy nuclei. • The Beta ray (β) is the emission of an electron or a positron. • The Gamma ray (γ) is observed in the two cases above. It is an electromagnetic wave (same nature as light). 1.2 Isotopes Two atoms are called isotopes if they have both the same number of protons and a different number of neutrons. Example : The carbon-14, written 14C, is the isotope of the 6 carbon-12 (the carbon that is mostly found at the natural state, written 12C). 6 1.3 Irradiation and Contamination • An object is irradiated when it is hit by a ionizing ray. It doesn’t make it radioactive. • An object is contaminated when there are radioactive elements on it. The result is that the whole is radioactive (object + radioactive dust). Dosis in Sv (Sieverts) Symptoms 0,1 Treshold below which one never has found any effect of radiation on health. 0,2 Threshold below we do not observe any symptoms.. 0,3 Small abnormalities on blood samples (less lymphocytes). 1 First clinical symptoms (nausea, vomiting). 2 Hospitalization necessary: bone marrow is affected (anemia, infections, bleeding). 3 First signs on the skin(redness), hair loss. 4,5 Lethal dose (50% mortality if untreated). 8 Bowel are reached (diarrhea) and respiratory functions too. Death follows after several days or weeks. 10 Neurological symptoms (coma) followed by death in several days or weeks. Sievert is a scale that marks the biological impact due to radiations. 1
  • 2. 2 The Electronic Components The electronics of the Geiger counter is made out of 3 main parts. The transformer, the Geiger tube and the signal stretcher. After having passed in the chop- per, the current coming from the bat- tery is transformed into alternating current. Then, the transformer am- plifies the voltage up to 400 Volts that is needed by the Geiger tube to work. This high voltage on the electrodes allows the current passing through the tube when a particle en- ters the tube. This event lasts only a few microseconds. If the signal was directly converted to a flashlight or sound, it would be to short to be seen or heard. For that specific reason, we added a signal stretcher that allows the signal to be long enough to be seen. Given that this is an digital cir- cuit, this means the output is either on or off and its state doesn’t depend on the intensity and speed of the particles. The Geiger tube is made of a metallic tube filled with ionizable gas in which are placed two electrodes. Above are represented the two different cases viewed from inside the Geiger tube. • When no particle enters the tube, no current can pass through the tube because the gas is not naturally conductive. • When a particle enters the tube, it is likely to grab electrons from the gas. This is called ionization and now the gas is conductive during a short moment. Therefore the current can pass through it. 2