Presentation is loading. Please wait.

Presentation is loading. Please wait.

5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 1 Introduction (What, who) Motivation (Why) Experiment and Polarimetry.

Published by Modified over 9 years ago

Similar presentations

Presentation on theme: "5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 1 Introduction (What, who) Motivation (Why) Experiment and Polarimetry."— Presentation transcript:

1 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 1 Introduction (What, who) Motivation (Why) Experiment and Polarimetry (How) Outlook Achim W. Weidemann University of South Carolina, Columbia (@SLAC) Polarized Positrons at a Linear Collider and FFTB (SLAC E-166)

2 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 2 E-166 Experiment E-166 is a demonstration of undulator-based polarized positron production for linear colliders E-166 uses the 50 GeV SLAC beam in conjunction with 1 m-long, helical undulator to make polarized photons in the FFTB. These photons are converted in a ~0.5 rad. len. thick target into polarized positrons (and electrons). The polarization of the positrons and photons will be measured.

3 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 3 E-166 Collaborators

4 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 4 Physics Motivation for Polarized Positrons Polarized e + in addition to polarized e - is recognized as a highly desirable option by the WW LC community (studies in Asia, Europe, and the US) Having polarized e + offers (next slides): Higher effective polarization -> enhancement of effective luminosity for many SM and non-SM processes Ability to selectively enhance (reduce) contribution from SM processes (better sensitivity to non-SM processes) Access to many non-SM couplings (larger reach for non- SM physics searches) Access to physics using transversely polarized beams (only works if both beams are polarized) Improved accuracy in measuring polarization.

5 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 5 –Electroweak processes e + e - -> WW, Z, ZH couple only to e - L e + R or e - R e + L (and not e - L e + L or e - R e + R ).  Can double or suppress rate using polarized positrons (in addition to pol. e-). –Effective polarization enhanced, and error decreased, in electroweak asymmetry measurements, (N L – N R ) / (N L + N R ) = P eff A LR, P eff = (P - - P + ) / (1 – P - P + ). - Improved accuracy in polarization measurement (Blondel scheme) ►Must have both e + and e - polarization for Giga-Z project (sin 2 θ W ) Physics Motivation for Polarized Positrons

6 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 6 (SUSY)Physics Motivation for Polarized Positrons Slepton and squark produced dominantly via (and not or ). Separation of the (LL, LR) selectron pair with longitudinally polarized beams to test association of chiral quantum numbers to scalar fermions in SUSY : With P(e-)= -80% and: P(e+)= 0% => no separation! P(e+)= -40% => 163fb vs 66 fb Can’t do without positron polarization!

7 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 7 Transverse polarization of both beams..allows separation of new physics, e.g. extra dimensions More examples in JLC, TESLA TDRs, Reviews, e.g. by G. Moortgat-Pick, (POWER [Polarization at Work in Energetic Reactions ] collaboration http://www.ippp.dur.ac.uk/~gudrid/power/ )… Next question: How to make polarized positrons? Physics Motivation for Polarized Positrons

8 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 8 Polarized Positrons at LC 2 Target assemblies for redundancy (+ polarized e- source)

9 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 9 50 GeV, low emittance electron beam 2.4 mm period, K=0.17 helical undulator 10 MeV polarized photons 0.5 r.l. converter target 51%-54% positron polarization Polarized Positrons at FFTB

10 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 10 E-166 is a demonstration of undulator-based production of polarized positrons for linear colliders (next slide): Photons are produced in the same energy range and polarization characteristics as in LC Same target thickness and material Polarization of the produced positrons is in the same range as at LC Simulation tools, diagnostics: same as those being used for LC polarized positron source But: the intensity per pulse is low by a factor of 2000. E-166 vs LC

11 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 11 LC / E-166 Parameter Comparison

12 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 12 Helical Undulator l=2.4 mm, K=0.17 Alexander A. Mikhailichenko, Pulsed Helical Undulator….CBN 02-10, LCC-106 Energy Polarization

13 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 13 Circ. γ -> long. e + polarization P(e + ) N(e + ) P(e + ) 0.5 r.l. Ti Alloy target; 0.5% yield, P(e + )=54% averaged over full spectrum Olsen & Maximon, 1959

14 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 14 Polarimeter Overview 1 x 10 10 e -  4 x 10 9  4 x 10 9   2 x 10 7 e + 2 x 10 7 e +  4 x 10 5 e + 4 x 10 5 e +  1 x 10 3  4 x 10 9   4 x 10 7 

15 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 15 Photon Transmission Polarimetry M. Goldhaber et al. Phys. Rev. 106 (1957) 826. For photons of undulator spectrum, use number- or energy-weighted integral.

16 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 16 1% stat. measurements very fast (~ minutes), main syst. error of ΔP  /P  ~ 0.05 from P e Expected Photon Polarimeter Performance Si-W Calorimeter Energy-weighted Mean Expected measured energy asymmetry δ = (E + -E - )/(E + +E - ) and energy-weighted analyzing power by analytic integration and, with good agreement, from polarized GEANT simulation: will measure P  for E  > 5 MeV; Aerogel Cerenkov

17 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 17 Polarimetry of Positrons 2-step Process: re-convert e+   via brems/annihilation process –polarization transfer from e+ to  well-known measure polarization of re-converted photons with photon transmission –infer P(e + ) from measured photon polarization Experimental Challenges: large angular distribution of the positrons at production target: –e+ collection & transport efficiency; - background rejection issues angular distribution of the re-converted photons –detected signal includes large fraction of Compton scattered photons –requires simulations to determine effective Analyzing Power 14-20% Formal Procedure: Stat. Error (~10 8 photons /15 minutes) δ(P) ~ 2 – 4 % Expected systematic Error of δ(P)/P ~5% dominated by eff. Magnetization of iron

18 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 18 Polarimetry Summary Transmission polarimetry is well-suited for photon and positron beam measurements in E166 Analyzing power determined from simulations is sufficiently large and robust Measurements will be very fast with negligible statistical errors Expect systematic errors of ΔP/P ~ 0.05 from magnetization of iron

19 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 19 Experiment approved mid-June 2003; …with proviso: should study backgrounds first; Installation under way now (Aug.2004) Will run Oct.2004, Jan 2005 (….before end of 2005, after which FFTB will become LCLS) Hope to blaze the way for polarised positrons at a future LC! E-166 Outlook For References, details see: http://www.slac.stanford.edu/exp/e166

20 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 20 Backup Slides

21 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 21 Positron Polarimeter Layout

22 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 22 Photon Detectors For Photons: Threshold Cerenkov (AeroGel) Si-W Calorimeter

23 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 23 Positron Transport System e+ transmission (%) through spectrometer photon background fraction reaching CsI- detector

24 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 24 CsI Calorimeter Detector Crystals: from BaBar Experiment Number of crystals: 4 x 4 = 16 Typical front face of one crystal: 4.7 cm x 4.7 cm Typical backface of one crystal: 6 cm x 6 cm Typical length: 30 cm Density: 4.53 g/cm³ Rad. Length 8.39 g/cm² = 1.85 cm Mean free path (5 MeV): 27.6 g/cm² = 6.1 cm No. of interaction lengths (5 MeV): 4.92 Long. Leakage (5 MeV): 0.73 % Photodiode Readout (2 per crystal): Hamamatsu S2744-08 with preamps

25 5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 25 Expected Positron Polarimeter Performance Expected systematic Error of δ(P)/P ~5% dominated by eff. Magnetization of iron

Download ppt "5 th Rencontres du Vietnam - Aug. 7, 2004 Polarized Positrons…E166 A.W.Weidemann 1 Introduction (What, who) Motivation (Why) Experiment and Polarimetry."

Similar presentations

Journées Instrumentation du GDR Nucléon 8-9 Avril 2008, CEA Saclay Polarized Positrons at the Jefferson Laboratory (i) Physics motivations (ii) Principe.

Journées Instrumentation du GDR Nucléon 8-9 Avril 2008, CEA Saclay Polarized Positrons at the Jefferson Laboratory (i) Physics motivations (ii) Principe.
POLARIMETRY of MeV Photons and Positrons Overview Beam Characterization – undulator photons – positrons Basics of the Transmission Method – for photon.

POLARIMETRY of MeV Photons and Positrons Overview Beam Characterization – undulator photons – positrons Basics of the Transmission Method – for photon.
The E166 Experiment K. Peter Schüler e+ source options for the ILC undulator source scheme for ILC E166 – proof-of-principle demonstration of the undulator.

The E166 Experiment K. Peter Schüler e+ source options for the ILC undulator source scheme for ILC E166 – proof-of-principle demonstration of the undulator.
1 Run 9 PHENIX Goals and Performance John Haggerty Brookhaven National Laboratory June 4, 2009.

1 Run 9 PHENIX Goals and Performance John Haggerty Brookhaven National Laboratory June 4, 2009.
Undulator-Based Positron Production in the Final Focus Test Beam (E-166) The International Polarized Positron Production Collaboration K.T. McDonald, J.C.

Undulator-Based Positron Production in the Final Focus Test Beam (E-166) The International Polarized Positron Production Collaboration K.T. McDonald, J.C.
K.T. McDonald DoE Review Aug. 10, 2006 19 E-166 Experiment E-166 is a demonstration of undulator-based polarized positron production for linear colliders.

K.T. McDonald DoE Review Aug. 10, E-166 Experiment E-166 is a demonstration of undulator-based polarized positron production for linear colliders.
EPAC June 2003 The EPAC June 2003 Questions 1. Clarify the Motivation for the Proposal. 2. How to ensure the e+ polarimeter works right away? 3. What is.

EPAC June 2003 The EPAC June 2003 Questions 1. Clarify the Motivation for the Proposal. 2. How to ensure the e+ polarimeter works right away? 3. What is.
E166 Collaboration J.C. Sheppard SLAC, October, 2003 E166 Background Test Simulations: Overview-what do we need J. C. Sheppard.

E166 Collaboration J.C. Sheppard SLAC, October, 2003 E166 Background Test Simulations: Overview-what do we need J. C. Sheppard.
Recent Electroweak Results from the Tevatron Weak Interactions and Neutrinos Workshop Delphi, Greece, 6-11 June, 2005 Dhiman Chakraborty Northern Illinois.

Recent Electroweak Results from the Tevatron Weak Interactions and Neutrinos Workshop Delphi, Greece, 6-11 June, 2005 Dhiman Chakraborty Northern Illinois.
E166 “Polarized Positrons for Future Linear Colliders” John C. Sheppard E166 Co-spokesman SLAC: August 31, 2004.

E166 “Polarized Positrons for Future Linear Colliders” John C. Sheppard E166 Co-spokesman SLAC: August 31, 2004.
K.T. McDonald DoE Review July 29, 2005 1 E-166 Experiment E-166 is a demonstration of undulator-based polarized positron production for linear colliders.

K.T. McDonald DoE Review July 29, E-166 Experiment E-166 is a demonstration of undulator-based polarized positron production for linear colliders.
Undulator-Based Production of Polarized Positrons Status Report on E-166 Undulator-Based Production of Polarized Positrons K.T. McDonald Princeton University.

Undulator-Based Production of Polarized Positrons Status Report on E-166 Undulator-Based Production of Polarized Positrons K.T. McDonald Princeton University.
E166 Collaboration About 45+2 members from 16+1 institutions from all three regions (Asia, Europe, the Americas, and Daresbury) About 45+2 members from.

E166 Collaboration About 45+2 members from 16+1 institutions from all three regions (Asia, Europe, the Americas, and Daresbury) About 45+2 members from.
Left: The polarization of the undulator radiation as a function of energy. Right: Calculated positron longitudinal polarization as a function of energy.

Left: The polarization of the undulator radiation as a function of energy. Right: Calculated positron longitudinal polarization as a function of energy.
NLC - The Next Linear Collider Project Sheppard/Pitthan June 26, 2015 Towards an Undulator Based NLC Positron Source Towards an Undulator Based NLC Positron.

NLC - The Next Linear Collider Project Sheppard/Pitthan June 26, 2015 Towards an Undulator Based NLC Positron Source Towards an Undulator Based NLC Positron.
K. LaihemE166 collaboration LCWS06 Bangalore March 12th 2006 The E166 experiment Development of a polarized positron source for the ILC. Karim Laihem on.

K. LaihemE166 collaboration LCWS06 Bangalore March 12th 2006 The E166 experiment Development of a polarized positron source for the ILC. Karim Laihem on.
Undulator-Based Production of Polarized Positrons An experiment in the 50 GeV Beam in the SLAC FFTB E-166 Undulator-Based Production of Polarized Positrons.

Undulator-Based Production of Polarized Positrons An experiment in the 50 GeV Beam in the SLAC FFTB E-166 Undulator-Based Production of Polarized Positrons.
Undulator-Based Positron Production in the Final Focus Test Beam (E-166) K.T. McDonald, J.C. Sheppard, Co-Spokespersons SLAC Experimental Program Advisory.

Undulator-Based Positron Production in the Final Focus Test Beam (E-166) K.T. McDonald, J.C. Sheppard, Co-Spokespersons SLAC Experimental Program Advisory.
E166 Collaboration About 45+2 members from 16+1 institutions from all three regions (Asia, Europe, the Americas, and Daresbury) About 45+2 members from.

E166 Collaboration About 45+2 members from 16+1 institutions from all three regions (Asia, Europe, the Americas, and Daresbury) About 45+2 members from.
NLC - The Next Linear Collider Project Rainer Pitthan Polarized Positrons A Close Look at Fukuda et al. There is much to be learned from the long effort.

NLC - The Next Linear Collider Project Rainer Pitthan Polarized Positrons A Close Look at Fukuda et al. There is much to be learned from the long effort.

Similar presentations

Ads by Google