Antimatter in the Lab 2 Rolf Landua CERN

Antimatter in the Lab (2) Rolf Landua CERN Summer Student Lectures 2011 - Part 2 1

Lectures 2 & 3 will focus on: Antiproton technology Discovery Antiproton beams and cooling Antiproton deceleration Antihydrogen Short history How to make antihydrogen How to trap antihydrogen Future developments Antimatter in daily life PET Antiproton therapy? Should Dan Brown get a Nobel prize? Antimatter (2) - Summer Students 2011 2

1955 - ANTIPROTON DISCOVERY First antiproton annihilation Nobel prize (1959) for 50% of the collaboration Tedious analysis …. Antimatter (2) - Summer Students 2011 3

Antiproton beams and cooling Antimatter (2) - Summer Students 2011 4

1978: Why antiprotons were needed at CERN Spp. S collider (270 Ge. V protons +270 Ge. V antiprotons) Goal: Discovery of W, Z bosons Other goals: search for Higgs, SUSY, top, . . . later: AD Antimatter (2) - Summer Students 2011 5

ANTIPROTON PRODUCTION Brute force: collide protons with nuclei pbeam + ptarget ➔ pbeam + ptarget + (p + p) But unfortunately: pbeam + ptarget ➔ pbeam + ptarget + (pions, kaons, …) First rule of quantum physics: Everything that is not forbidden MUST HAPPEN Production of antiprotons competes with all other processes Antimatter (2) - Summer Students 2011 6

Acceleration efficiency ~ 10 -3 Production efficiency ~ 10 -4 Collection efficiency (AD) ~ 10 -2 Overall (energy) efficiency ~ 10 -9 Antimatter (2) - Summer Students 2011 7

Efficiency of antiproton production - increases with primary energy : Fermilab 26 Ge. V (CERN) : 2 · 10 -4 per proton 120 Ge. V (Fermilab): 1. 5 · 10 -3 per proton PS at CERN Antimatter (2) - Summer Students 2011 Higher initial momentum of proton beam higher final momentum of antiprotons 8 ->

1980 - Construction of Antiproton Accumulator Goal: Intense antiproton beams - capture antiprotons at 3. 5 Ge. V/c - optimized for PS proton energy - increase phase space density ~ 1011 (1987, AC: 1012) antiprotons/day - Investment ~ 100 MCHF Antimatter (2) - Summer Students 2011 9

ANTIPROTON COOLING TECHNIQUES Electron cooling (Novosibirsk, Budkers 1966) works well > 1 Ge. V/c Antimatter (2) - Summer Students 2011 works well < 1 Ge. V/c 10

Antiproton deceleration Antimatter (2) - Summer Students 2011 11

WHY ANTIPROTON DECELERATION ? allows to produce lots of antiprotons at low energy (many orders of magnitude more than in “secondary beams”) Only possible with beam cooling Antimatter (2) - Summer Students 2011 12

1982 -1996: LOW ENERGY ANTIPROTON RING (LEAR) “ The 3 -accelerator scheme “ Production Accumulation Deceleration (3. 5 -> 0. 6 Ge. V/c) Cooling+Deceleration/Acceleration (0. 1 - 2 Ge. V/c) LEAR was built as an ‘appendix’ to the CERN antiproton collider programme Antimatter (2) - Summer Students 2011 13

First antihydrogen production in flight (LEAR, 1995) Annihilation of 9 anti-atoms ~ 2 n. J ~ Lifting a mosquito by 1 µm Antimatter (2) - Summer Students 2011 14

CERN learned much about P. R. . . The World started to fear CERN’s antimatter bombs Antimatter (2) - Summer Students 2011 15

Fear of CERN antimatter bombs only lasted 12 years Sep 10, 2008: The LHC will destroy the Earth Antimatter (2) - Summer Students 2011 16

1996: LEAR stopped But - what about antihydrogen? Solution: transform AA+AC --> AD Approved. . . 1997 Antimatter (2) - Summer Students 2011 17

Possible precision measurements with slow or trapped antihydrogen 1) 1 S-2 S spectroscopy (ATHENA/ALPHA, ATRAP) 2) Hyperfine structure of 1 S ground state (ASACUSA) 3) Gravitational acceleration (AEGIS) Antimatter (2) - Summer Students 2011 18

Challenge of slow antihydrogen production Antiprotons and positrons (when young) are hot Hydrogen atom is a weakly bound system: E (1 s) = - 0. 000 013 6 Ge. V Constituents need to chill before mating Antimatter (2) - Summer Students 2011 19

2000: Antiproton Decelerator (AD) “ The all-in-one solution “ AEGIS ALPHA 5 experiments (2011): ATRAP, ASACUSA, ACE, ALPHA, AEGIS Antimatter (2) - Summer Students 2011 20

How the Antiproton Decelerator works Antimatter (2) - Summer Students 2011 21

The AD - a machine and its team AD Hall RF cavity Antimatter (2) - Summer Students 2011 22

ANTIHYDROGEN @ AD @ CERN Antiproton trapping Positron trapping Antihydrogen production Antihydrogen trapping Outlook Antimatter (2) - Summer Students 2011 23

Antiproton trapping KEY ELEMENT - PENNING TRAP For trapping: ~ several k. V Storage: ~ 1 -20 V Antimatter (2) - Summer Students 2011 24

ANTIPROTON CAPTURE WITH DEGRADER Miserable efficiency (0. 2 - 1 %) Antimatter (2) - Summer Students 2011 25

PENNING TRAPS USED AT AD ASACUSA trap Antimatter (2) - Summer Students 2011 26

How CERN really became famous 2000: Start of CERNs ‘Antimatter Factory’ (AD) Antihydrogen experiments started (ATHENA, ATRAP) Visit of Dan Brown (Dan Who? ) 2009: Angels+Demons movie Antimatter (2) - Summer Students 2011 27

Any resemblance ? Two magnets, some electrodes. . . could work Antimatter (2) - Summer Students 2011 28

Hollywood version of ‘Antiproton Capture’ (from “Angels & Demons”) Antimatter (2) - Summer Students 2011 29

In Lecture 3 you will find out why this does not work so well at the LHC. . . Antimatter (2) - Summer Students 2011 30

Lecture 3 Slow antihydrogen production Trapping ! Outlook Antimatter in daily life ? Antimatter (2) - Summer Students 2011 31

To keep you awake: What did Ron Howard* say after he had seen CERN on his first visit in 2007? That’s how small I feel after seeing this huge detectors. . . That’s the budget of my new movie “Angels and Demons” This much science will be in the “Angels and Demons” movie. . . This is what Dan Brown understands about antimatter. . *Angels&Demons, Da Vinci Code, Apollo 13, Beautiful mind, . . . The correct answer at the end of this lecture. . Antimatter (2) - Summer Students 2011 32

Positron trapping 100 million positrons accumulated in 2 min Antimatter (2) - Summer Students 2011 33

Production of ‘slow’ antihydrogen p- and e+ in mixing trap (cooling) Antihydrogen formation AD Na-22 p- Production (Ge. V) e+ Production (Me. V) Deceleration (Me. V) 108 e+ 104 p- Moderation Accumulation (e. V) Trapping (ke. V) Cooling (me. V) Detection of annihilation Needs trapping of antiprotons and positrons Antimatter (2) - Summer Students 2011 34

First SLOW antihydrogen production (ATHENA, 2002) Antimatter (2) - Summer Students 2011 35

ATHENA experiment Antimatter (2) - Summer Students 2011 36

Recombination option 1: Nested Penning trap Antimatter (2) - Summer Students 2011 37

Antihydrogen detection (ATHENA) Charged particles 2 layers of Si microstrip detectors 511 ke. V gammas 192 Cs. I crystals Inner radius 4 cm, thickness ~ 3 cm 70% solid angle coverage Operates at 3 Tesla, 140 Kelvin Event analysis: • 1. 2. Reconstruct vertex from tracks of charged particles Identify pairs of 511 ke. V γ -rays in time coincidence Measure opening angle between the two γ -rays Antimatter (2) - Summer Students 2011 38

ATHENA: proof of antihydrogen production Opening Angle Distribution Peak from back-to-back 511 ke. V photon pairs Test: peak disappears when positrons are ‘heated’ (RF) Antimatter (2) - Summer Students 2011 39

Initial production rate ~ 100 Hz ATHENA, 2002 Antimatter (2) - Summer Students 2011 40

Recombination via positronium (AEGIS, ATRAP) Laser excitation defines ‘start’ of antihydrogen production Antimatter (2) - Summer Students 2011 41

Alternative antihydrogen detection: *FIT : Field Ionization Trap Find antiprotons where they should not be. . (Method used by ATRAP and ASACUSA) Antimatter (2) - Summer Students 2011 42

Fate of produced antihydrogen atoms: Annihilation on electrode walls within few µs Antimatter (2) - Summer Students 2011 43

Antihydrogen trapping Antimatter (2) - Summer Students 2011 44

Antihydrogen is neutral, but. . . it has a magnetic moment (~ μ e+) try to trap slowest atoms with strong magnetic field gradient Antimatter (2) - Summer Students 2011 45

Example: Sextupole magnet Low field seeking atoms (50%) at r=0 BUT: Very shallow potential (~ 0. 07 me. V/T) 1 T depth ~ 0. 7 K temperature: Hope for low energy ‘Boltzmann tail’ Antimatter (2) - Summer Students 2011 46

ALPHA EXPERIMENT - Setup New feature: Octupol magnet Antimatter (2) - Summer Students 2011 47

ALPHA EXPERIMENT - Movie Antimatter (2) - Summer Students 2011 48

ALPHA EXPERIMENT - Results Trapping yield - 2010 : 38 antihydrogen (0. 17 sec) 5· 10 -5 (0. 11 per 5000 anti-atoms/cycle) - 2011 : 252 antihydrogen (15 min) 4· 10 -4 (~0. 9 per 5000 anti-atoms/cycle) Next: Cooler antiprotons (evaporative cooling) higher trapping yield (need more antihydrogen per cycle) first resonant interactions using laser Antimatter (2) - Summer Students 2011 49

Alternative option : Laser cooling ? 121. 5 nm laser needed (Lyman-Alpha; 1 S-2 P transition) Prototypes exist … only 50 n. W (10 µW needed) Antimatter (2) - Summer Students 2011 50

Future of AD experiments ELENA - Extra-low energy antiprotons! ASACUSA - 1 s HFS of antihydrogen AEGIS - Gravity measurement Antimatter (2) - Summer Students 2011 51

Extra-Low Energy Antiprotons (ELENA) (operational in 2016) 23 m ring 5. 3 Me. V -> 100 ke. V Trapping efficiency ~ 100% Start construction: 2013 35 Antimatter (2) - Summer Students 2011 52

ASACUSA Antihydrogen 1 S Hyperfine structure Antimatter (2) - Summer Students 2011 53

ASACUSA - Antihydrogen 1 S Hyperfine structure Antimatter (2) - Summer Students 2011 54

ASACUSA: EXTRACTION OF ANTIHYDROGEN BEAM + Ramsey-type measurements (spin flip) Antimatter (2) - Summer Students 2011 55

Antihydrogen in flight (AEGIS) [Antimatter Experiment: Gravity, Interferometry, Spectroscopy] Antimatter (2) - Summer Students 2011 56

AEGIS: Gravitational deflection Counts vs. vertical coordinate a) no gravity, very high statistics Anti. Hydrogen a = 80 μm Grating period a = 80 μm Grating size = 20 cm (2500 slits) Antimatter (2) - Summer Students 2011 57

Aim at ~ 1% precision b) with gravity v =250 m/s v =600 m/s gt² δ=― a start: laser excitation of positronium stop: annihilation signal TOF: velocity Antimatter (2) - Summer Students 2011 58

Antimatter in daily life PET scan Antiproton therapy? What about bombs? Should Dan Brown get a Nobel prize? Antimatter (2) - Summer Students 2011 59

POSITRON EMISSION TOMOGRAPHY (PET SCANNER) e+ emitting isotopes (C-11, N-13, O-15, F-18) physiologically relevant molecules (O 2, glucose, . . ) inject into patient. Reconstruct place of positron annihilation with crystal calorimeter Antimatter (2) - Summer Students 2011 60

TUMOUR TREATMENT: Gammas, protons, antiprotons? Goal: destroy tumour without (too much) harm to healthy tissue Gammas: exponential decay (peaks at beginning) Protons: Bragg peak (Plateau/Peak better for high Z) Antimatter (2) - Summer Students 2011 61

ACE - Antiproton Cell Experiment Biological effectiveness of antiproton annihilation in cells Additional damage by nuclear fragments of short range Chinese Hamster Cells Antimatter (2) - Summer Students 2011 62

ACE: result Equal cell mortality for tumour cells : less than 1/2 proton radiation dose Antimatter (2) - Summer Students 2011 63

At the end, the really big questions: Where is the secret antimatter lab ? Do we have 1 gram of antimatter ? Can we build a bomb ? Antimatter (2) - Summer Students 2011 64

What about antimatter bombs ? Dan Brown is right: only 0. 5 g antimatter makes an ‘anti-atomic bomb’ BUT: 0. 5 g antimatter = 4. 5 · 1013 J Total energy needed (efficiency =10 -9 ) : 4. 5 · 1022 J Electricity discount price CERN [1 k. Wh = 3. 6 · 106 J = 0. 1 €] 20 kt TNT = 8. 4 · 1013 J 0. 5 g antimatter + 0. 5 g matter Antimatter (2) - Summer Students 2011 Price ~ 1, 000, 000 € Delivery time ~ 1 000 000 years 65

. . . and the solution to the Ron Howard question: What did Ron Howard say after a visit to CERN? Antimatter (2) - Summer Students 2011 66

THANK YOU FOR YOUR ATTENTION Antimatter (2) - Summer Students 2011 67