1. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 1 Closer to Reality From Last Talk ( 7-Jan-06) – things seemed Great! However... 1) In estimating the SRD I use the normalized (true) Extra Galactic Diff Rate instead of our absolute(meas.) rate... Iissue: the acceptance (Aeff) falls off at lower energies (there's almost a factor of 3 here) 2) Our intend operational mode is "Rocking" exposing our backside Issue: Large gaps between CalModules (there's another factor of ~ 1.3 here) This analysis: Input: 1) First day of 5B Bkg. Run: dataset v7r3p5 (Includes rocking) 2) Extra Galactic Diff: dataset v7r3p5 3) All Gamma rep-V7r3p4 dataset, runs 401-800 All these datasets are "CTnew" mean application of the cuts shown by Julie prior to download

2. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 2 Input: CTnew FT1ZenithAngle > 100 High Energy e- Filter Scrambled Tkr Filter Heavy Ion Filter.0.3.4.5.65.75 SRD 1:1 Background and Diffuse Integral Rates 100 200 500 1000 2000 5000 10000 E min CTBGAM CTBCORE >.1 && CTBBestEnergyProb.1 Base Class 1: CTBGAM >.35 Base Class 3: CTBGAM >.55 see next chart for Filter Definitions

3. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 3 ( (min(abs(Tkr1XDir),abs(Tkr1YDir)) 0 & AcdActDistTileEnergy >.2) | (Tkr1SSDVeto -3 & AcdActDistTileEnergy >.15) | ( AcdActiveDist3D >(-30 + 30*(Tkr1FirstLayer-2))) ) & CTBBestEnergy > 5000 Hi Energy e- Filter: Heavy Ion Filter: CTBBestEnergy > 5000 & ((CalTransRms - 1.5*Tkr1ToTTrAve) < 5) (Tkr1FirstLayer - Tkr2FirstLayer) 4 & Tkr2TkrHDoca > 100 Scrambled Track Filter: Cosmic Proton: Tkr1FirstLayer -80 & ((AcdActDistTileEnergy + AcdActiveDist3D/100) > 1)

4. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 4 Base Class 3: CTBCORE >.35 && CTBBestEnergyProb >.35 Same Contours as before Base Class 3: CTBGAM >.50

5. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 5 On Axis Aeff x FoV Base Class 3 Cuts THIS ONE

6. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 6 Bkg. Diffuse Base Class 3 Cuts

7. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 7 Hadronic Res. Bkg. QED Res. Bkg. 100-500 MeV 500-2500 MeV 2500-12500 MeV > 12500 MeV Residual Background Broken out by Sources and CTBBestEnergy Irreducible: e+ Conversions Cosmic (Hi E) e- Cosmic Protons – ACD Leakage? Same energy bins as above Correlated  's!

8. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 8 ACD Leakage Correlated Events: McDirErr <.1 and not e+ McId != -1 72 events Side Ribbons don't go to top! Estimate 47 events are leaked in this way These are the Top Corner Leakers found in the hand-scan Require events start in Top Layer Tkr1Z0 > 590 Composition:

9. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 9 Project Tracks to + Const. X Sides and fold to YSide > 0: YSide = min(abs(Tkr1Y0 - abs( (832-abs(Tkr1X0))/Tkr1XDir) * Tkr1YDir), 742) ZSide = min(abs(Tkr1Z0 - abs( (832-abs(Tkr1X0))/Tkr1XDir) * Tkr1ZDir), 800) All Data Data Inside Holes All Gamma Ineff. = 90/105090 =.1%

10. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 10 Suspect the same is true on Const. Y Sides – Evidence poor – Const. X Sides Holes Removed Both Sides Holes Removed Difference Combined: BKG: 209 DIFF: 63 GAM: 220

11. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 11 Remaining Base Class 3 Residuals Hadronic QED Next step: separate out the CTBBestEnergy > 1 GeV and hand scan 69 Events after X,Y Side Holes

12. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 12 P Primary 12.17GeV Tracking error in Y e+ Back-Entering 1.71GeV Shower Stub in Tracker Uncorrelated Events

13. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 13 P Primary 32.55 GeV Acd Tile McPosHit 49KeV Ribbon Slot (10 of these) P Primary 4..494GeV Acd Tile McPosHit 1.57 MeV No ACD Digi Correlated Events

14. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 14 e- cosmic 6.65 GeV Ribbon Ineff. And so on...

15. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 15 Speculation: We may be able to kill most(all) of the Correlated Bkg. > 1 GeV If so where will we be - Present Status Corr. Bkgs. Removed Goal  = 35 events

16. Bill Atwood, SCIPP/UCSC, Jan. 30, 2006 GLAST 16 Top Ribbon Ineff. And... 45% Already There: 16 of these events are CTBBestEnergy > 1 GeV Req. CTBBestZ0 > 590 (Starts at the Top) & McDirErr <.1 (Correlated Event) This will be an issue on the sides as well Need DOCA to nearest Ribbon whether or not it was hit.... 69 Events Total (out of 365)