D FPD Introduction Bellows Andrew Brandt UTA Roman

DØ FPD Introduction Bellows Andrew Brandt UTA Roman Pot p p Detector P 1 UP P 2 OUT S D D 2 D 1 59 57 Q 2 Q 3 Q 4 A 2 A 1 33 23 Q 4 Q 3 Q 2 S P 1 DN 0 23 P 2 IN 33 Z(m) February 20, 2003 FPD mini-workshop Fermilab

EVENT TOPOLOGIES

Diffractive Variables p. Beam p. F P Pomeron Exchange Non-diffractive For Te. V For Ge. V (Note: Ge. V )

Diffraction Thesis Topics Soft Diffraction and Elastic Scattering: Inclusive Single Diffraction Elastic scattering (t dependence) Jorge Molina Total Cross Section Centauro Search Inclusive double pomeron Search for glueballs/exotics Hard Diffraction: Diffractive jet Michael Strang E Diffractive b, c Diffractive W/Z Diffractive photon Diffractive top <100 events in Run I, >1000 Diffractive Higgs tagged events in Run II Other hard diffractive topics Double Pomeron + jets Tamsin Edwards Other Hard Double Pomeron topics Rapidity Gaps: Central gaps+jets Gap tags vs. proton tags Double pomeron with gaps Topics in RED were studied with gaps only in Run I

Data Taking • No special conditions required • Read out Roman Pot detectors for all events (can’t miss ) • A few dedicated global triggers for diffractive jets, double pomeron, and elastic events • Use fiber tracker trigger board -- select , |t| ranges at L 1, readout DØ standard • Reject fakes from multiple interactions (Ex. SD + dijet) using L 0 timing, silicon tracker, longitudinal momentum conservation, and scintillation timing • Obtain large samples (for 1 fb-1): ~ 1 K diffractive W bosons ~ 3 K hard double pomeron ~500 K diffractive dijets with minimal impact on standard DØ physics program

Quadrupole ( p or ) 450 400 MX(Ge. V) 350 280 200 Dipole ( only) Ge. V 2 450 400 350 280 200 Dipole acceptance better at low |t|, large Cross section dominated by low |t| 0 0. 02 0. 04 Quadrupole 1. 4 1. 3 Dipole 2 35 95 Ge. V 2 MX(Ge. V) Geometric ( ) Acceptance

Roman Pot Castle Design 50 l/s ion pump Worm gear assembly r to c e t De Beam Step motor • Constructed from 316 L Stainless Steel at LNLS, Brazil • Parts are degreased and vacuum degassed • Plan to achieve 10 -11 Torr • Use Fermilab style controls • Bakeout castle, then insert fiber detectors

Roman Pot Arm Assembly Threaded Cylinder Motor Detector is inserted into cylinder until it reaches thin window Bellows Thin window and flange assembly (NIKHEF) Flange connecting to vacuum vessel

Girder Reconfiguration Bypass BEFORE: Sep Sep Girder Tunnel Floor Pit Floor Run I Girder Configuration AFTER: Bypass Pot Sep Sep Pot p Sep Girder Pit Floor Hole in Floor Run II Girder Configuration

Castle Status All 6 castles with 18 Roman pots comprising the FPD were constructed in Brazil, installed in the Tevatron in fall of 2000, and have been functioning as designed. A 2 U pot had vacuum leak and was disabled for 6 months and fixed during Jan. 2003 shutdown. Quadrupole castle A 2 installed in the beam line.

Detector Assembly At the University of Texas, Arlington (UTA), scintillating and optical fibers were spliced and inserted into the detector frames.

Detectors in Cartridges The plastic frames containing the clear fibers are attached to the cartridge bottom (cartridges built at NIU and UTA). The cartridge bottom containing the detector is installed in the Roman pot and then the cartridge top with PMT’s is attached.

Tunnel and Detector Status • All 18 cartridges have been assembled, 16 are installed in tunnel (10 with full detectors 6 with trigger scint). The 10 instrumented pots (Phase I) are ups, downs, and dipoles. • Cables and tunnel electronics (low voltage, amp/shapers, etc. ) installed and operational for full 18 pot (Phase II) setup. • 10 more detectors (includes 2 spares) are complete except for final polishing, which is in progress at Fermilab.

Veto Counters In the October 2001 shutdown four veto counters (designed at UTA, built at Fermilab) each of which cover 5. 2 < | | < 5. 9 were installed between DØ and the first low beta quadrupole (Q 4), about 6 m from the interaction point. The counters, two each on the outgoing proton and anti-proton arms, can be used in Diffractive triggering (veto proton remnant).

Pot Motion Pot motion is controlled by an FPD shifter in the DØ Control Room via a Python program that uses the DØ online system to send commands to the step motors in the tunnel.

Pot Insertion Monitor Effect of the pot motion on the proton and antiproton losses at DØ and CDF is monitored using ACNET. Current agreement with Beams Division and CDF requires that the effect on halo rates is less than 10%.

Stand-alone DAQ • Due to delays in DØ trigger electronics, we have maintained our stand-alone DAQ first used in the fall 2000 engineering run. • We build the trigger with NIM logic using signals given by our trigger PMT’s, veto counters, DØ clock, and the luminosity monitor. • If the event satisfies the trigger requirements, the CAMAC module will process the signal given by the MAPMT’s. • With this configuration we can read the fiber information of only two detectors, although all the trigger scintillators are available for triggering. • An elastic trigger was formed from coincidences of the PU+AD spectrometers combined with halo vetoes (early time hits) and vetoes on LM and Veto counters.

FPD Control Room

Elastic , t (calibrated) Calibrated now peaks at 0 Minimum t about 1. 0 Gev 2 peak reasonably Gaussian, still 2 x ideal MC resolution

Proton ID The Proton ID group led by Moacyr Souza and Sergio Novaes has made substantial progress in many software areas: • Track reconstruction • Monte Carlo • Unpacking • Single Interaction Tool • Alignment • Database Regular Proton-ID meetings are held Thursdays 11 -12: 30 in West Wing using VRVS

FPD Summary • FPD will (soon) be a completely integrated subdetector of the DØ detector which will help maximize Run II physics potential • Hard diffraction exists, but not well-understood -- large data samples and precise measurements needed • Large and L at Tevatron necessary for these measurements • Combination of quadrupole and dipole spectrometers gives ability to tag both p’s and p ’s over large kinematic range, allows alignment, understanding of backgrounds • Tremendous progress in installation and commissioning, emphasis currently on trigger, software, operations, and data analysis • FPD detectors work, physics just around the corner