Milagro status report october 1998
1 / 36

Milagro Status Report - October 1998 - PowerPoint PPT Presentation

  • Uploaded on

Milagro Status Report - October 1998. Physics Goals and Status of Milagro. October 1998 The Milagro Project Physics Goals Overall Design Milagrisimo - Milagrito - Milagro Comparison of Milagro to other detectors Milagrito The Detector Operations Results Status -

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Milagro Status Report - October 1998' - rollo

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Physics goals and status of milagro
Physics Goals and Status of Milagro

October 1998

The Milagro Project

  • Physics Goals

  • Overall Design

  • Milagrisimo - Milagrito - Milagro

  • Comparison of Milagro to other detectors

  • Milagrito

    • The Detector

    • Operations

    • Results

  • Status -

    • Milagro Installation Schedule

    • Budget History

  • The milagro collaboration october 1998
    The Milagro CollaborationOctober 1998

    M.L.Chen, and J.A. Goodman,* G. Sullivan, D. Evans

    University of Maryland At College Park

    A. Shoup, and G.B. Yodh,

    S. Hugenberger, I. leonor

    University of California, Irvine

    D.G. Coyne, D.E. Dorfan, L.A. Kelley D.A. Williams S. Westerhoff

    W. Benbow, J. McCullough, M. Morales, T. Yang

    University of California, Santa Cruz

    A.I. Mincer, and P. Nemethy, L. Fleysher, R. Fleysher

    New York University

    R.W. Ellsworth

    George Mason University

    D. Berley

    National Science Foundation

    G. Gisler, T. J. Haines, C.M. Hoffman*, R. Miller,

    and C. Sinnis

    Los Alamos National Laboratory

    B. Shen, A. Smith , O.T. Tumer,

    K. Wang, M. Wascko

    University of California, Riverside

    M. McConnell, J. Ryan, A. Falcone

    University of New Hampshire

    B. Dingus, J. McEnery, R. Atkins

    University of Utah

    *Spokesmen Students

    NSF EP SupportedGroups

    Doe & other



    High energy cosmic ray detectors
    High Energy Cosmic Ray Detectors

    The Cosmic Ray Spectrum








































    Solar Arrays

    Air Cherenkov


    EAS Arrays

    Fly’s Eye / HiRes

    Akeno /Auger


    • A Water Cherenkov Detector

      • Sensitive over 100% of the area

      • Sensitive to Photons and Electrons

    • A Low Threshold - Open Aperture Detector

      • Threshold < 300 GeV

        • Significant Area at 100 GeV

      • Large Duty Cycle

      • Acceptance ~ 1sr

      • Angular Resolution < 0.50 (better for large showers)


    • Built in an Existing 60x80x8m Pond

      • 450 Top layer 8” PMT’s on 3m grid

      • 273 Hadron/mlayer PMT’s (facing up)

    • High Altitude Location - 8650’

      • Existing Lab Tech Area

      • Support Facilities at the Site

    Physics with milagro
    Physics with Milagro

    • First All Sky Survey of the Northern Sky

      • Search for DC Signals

      • Look for New Sources

      • Search for Bursts on Many Time Scales

    • Study the Signal from the Crab

      • Milagro will observe the Crab with >5s in a few months (using the Whipple Flux)

      • Milagro will study the spectrum & flux

        • Absolute flux normalization from ACT’s is important and needs to be confirmed

        • Data on the high energies is needed for acceleration models

    • Search for Gamma Ray Bursts

      • EGRET has seen burst events up to ~20 GeV with Aeff of ~400 cm2

      • Milagro at 100 GeV will have Aeff» 20 m2 (more than ~500 x EGRET)

      • Milagro’s acceptance grows like E2 up to 1 TeV

      • Milagro operates continuously with a wide aperture - It will be the best high energy GRB detector!

      • Measuring a cutoff above a TeV would constrain GRB models and distance to the source

    Physics with milagro1
    Physics with Milagro

    • Study AGN’s

      • MRK 501 has be seen by Milagrito

      • EGRET has seen >30 AGN’s

      • Milagro will search for variability in AGN’s at TeV energies

        • Sources have shown increases x ~100

        • All northern sources can be viewed every day with Milagro

        • Correlation with Radio Observations

      • HEGRA has events at >20 TeV from Mrk501

      • The nature of the spectrum above a few TeV is important in determining where / if absorption is occurring

    • Primordial Black Holes

      • PBH’s will radiate energetic particles at the end of their lifetime

        • The spectrum of particles radiated will be depend on physics model - SUSY etc.

      • Milagro will be sensitive to the last few minutes of a PBH explosion

      • Cygnus set limits on PBH that were 100x better than any other

      • Milagro should do about 2-3 orders of magnitude better

    Primordial black holes
    Primordial Black Holes

    • PBH’s will radiate particles at the end of their life

      • The radiation will depend on the number of degrees of freedom

      • Milagro will be sensitive to particles produced in the last ~1000 seconds

    Physics with milagro2
    Physics with Milagro

    • Solar Physics

      • Milagro will detect the shadow of the sun in a few days

      • The position and disappearance of the shadow are a measure of the solar Bperp

        • Currently measurements are poor

      • GeV Solar flares give muons in the bottom layer

        • 2500 m2 will allow us to measure solar flare structure on a 1 sec time scale vs 10’s of minutes

      • Milagrito already has a probable detection of a CME event

      • Proposal to ATM from UNH (muon direction)

    • Antimatter Search

      • There will be a second displaced shadow if there is a significant amount of antimatter

    • Composition Studies

      • Wide Area Cherenkov Telescope Proposal


    • Milagrisimo was the first stage of Milagro

      • 30 PMTs were operated in the Milagro Pond in winter of 1995-1996

      • Single layer on the bottom of the Pond

      • ~1.5m of water above tubes

      • Design studies and analysis presented in at Durban ICRC


    • Milagrito was the second stage of the Milagro detector

      • It was a large area water detector

        • Area ~ 2/3 Milagro

        • No Muon Layer

      • Milagrito data was used for:

        • design studies and development

      • And it will be used for physics & theses

        • Physics (MRK 501, GRB’s etc)

        • Student Theses

    Milagrito operated at >250Hz from

    February 1997 to April 1998 (>85% livetime)

    More than 9 billion events - 9 Terabytes


    One Month Coverage

    Milagrito results
    Milagrito Results

    • Moon Shadow

      • Offset is approximately what is expected at our energies.

    Antimatter shadow location

    Milagro site
    Milagro Site

    Milagro Site

    HDR Site

    Ops Building

    Million Gallon Pond

    Milagro site1
    Milagro Site

    Pond Utility Building (PUB)

    Counting House

    Testing Trailer

    Office Trailer

    Milagro construction
    Milagro Construction

    Cover Inflated with new webbing

    Lightning protection system

    Milagro construction1
    Milagro Construction

    4 Muon Boxes deployed to provide redundant ID


    • Milagro will have a trigger rate of ~2 kHz

      • Data will be processed in real time

      • Will perform online search for bursts

      • Time and pulse height on each channel

    • The muons will provide substantial background reduction for showers above a few TeV

      • <Nmu>detected = 1 at 1 TeV

      • At high energies Milagro will have low background

    • Muon/Hadron layer may provide other methods of background rejection

      • A real gamma signal can be studied from sources like the Crab to develop better rejection algorithms

    • Water tanks are needed to surround the pond to get core position

      • Core position is needed for angular resolution and energy determination

    Why we need outriggers
    Why We Need Outriggers

    • What are outriggers?

      • An array of water tanks outside the pond

      • We have built & operated a prototype

      • Outriggers were part of the original Milagro proposal

    • Outriggers are essential for locating core position

      • Need counters outside the pond to tell if cores are inside or outside

    • Energy Determination needs core position

      • Need core to determine shower size and lateral distribution - This is vital for AGNs and GRBs

    • Angular Resolution

      • Curvature correction needs core position

    • Proton/Gamma Discrimination

      • Proton showers trigger further from the pond

      • Gammas trigger more often on the pond

    Major responsibilities on milagro
    Major Responsibilities on Milagro

    • Milagro is a strong collaboration of University Groups and Los Alamos

      • A project supported by both NSF & DoE

      • All groups share responsibility for operating the detector

    • Irvine

      • PMTs - testing, encapsulation…

    • Los Alamos

      • Operations

      • Site

    • Santa Cruz

      • Electronics

      • Cover Inflation system

      • Lightning Protection

    • Maryland

      • DAQ

    • New Hampshire

      • Solar

      • Outriggers

    • NYU

      • PMT structure and deployment

    • Utah

      • WACT

    Timeline funding profile
    Timeline & Funding Profile

    • 1994 Funding begins toward a $2.6M Project (80%NSF 20%DoE)

    • 1995 Site Preparation - New liner & cover - PUB - Counting House - PMT structure installed

    • 1995 -1996 Milagrisimo run - 38 tubes on pond bottom

    • 1996-1997 Milagrito installed - Data taking begins Feb 1997

    • 1997 Lightning protection system

    • 1998 Milagro tubes installed, modifications to electronics, cover, water system completed (based on Milagrito experience)

    • Winter 1998-1999 Running to begin







    • Milagro is an important new detector that will produce significant new physics results

      • GRB, AGNs, Solar Physics, PBH, Antimatter, Composition

    • Milagro has a strong collaboration

      • NSF Groups, DoE Groups & Los Alamos

    • Milagro has been built in stages

      • We have learned how to build and operate the detector through prototypes

    • The project has been on time and on budget

      • We built it for the cost proposed in 1991

      • We built as fast as the cash flow allowed

      • We have met all the technical challenges

    • Outriggers are essential to finish to Milagro

      • Core position is central to Milagro’s goals

      • Proposal this winter for outriggers

    • Solar Physics is an added bonus

      • Solar Proposal to ATM

    Primordial black holes1
    Primordial Black Holes

    • Why might they exist?

      • Density Fluctuations in the early universe- Some regions of space could become overdense and collapse

    • What did COBE tell us?

      • COBE studied density fluctuations on a huge scale (1055gm) and founddr/r < 10-5

    • Other evidence

      • Standard inflation says dr/r is scale invariant

      • If Standard inflation and COBE are correct - There should be virtually no PBH’s

      • Diffuse 100 MeV g’s set a limit on the number of PBH’s WPBH<10-8

    • If PBH’s do exist - We might see them when they evaporate

      • T ~ 1/M

      • They would radiate all species of particles at the end of their lifetime

      • Initial mass of ~1015 gm would be going off now

      • We should look at a scale 40 orders below COBE