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Options for E906/Drell-Yan with a Solid Iron Magnet (Fe906?) Paul E. Reimer 20 June 2008. Solid Iron magnet Target dump separation Chamber rates Resolution—Mass, x F , x 1 , x 2 Acceptance. Why a Solid Iron Magnet?. E906 budget is very tight.

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Options for e906 drell yan with a solid iron magnet fe906 paul e reimer 20 june 2008

Options for E906/Drell-Yan with a Solid Iron Magnet(Fe906?)Paul E. Reimer20 June 2008

Solid Iron magnet

Target dump separation

Chamber rates

Resolution—Mass, xF, x1, x2

Acceptance


Why a solid iron magnet
Why a Solid Iron Magnet?

  • E906 budget is very tight.

    • We are expecting ≈$2M for DOE/Nuclear Physics. Of this $1.6M will be used to produce coils for an open aperture magnet. The remainder is for spectrometer upgrades.

    • NSF, Taiwan and Japan are planning contributions to the spectrometer upgrades

  • Fermilab has requested that we contribute an additional $1.5M for M&S that they need to spend for E906

    • Some tasks e.g. flammable gas system (Illinois) and cryotargets may be done by collaborators.

    • RIKEN may to contribute ≈$600k to “common fund” items

    • Still short ≈$500k

  • Solid Iron Magnet

    • Essentially free—coils and iron exist, Iron must be cut ($100k)

    • Reprogram DOE/ONP funds to Fermilab (Under discussion with Brad Tippens)

    • Increased acceptance--larger “aperture” (if you can call it that)

    • Decreased resolution

Paul E. Reimer


Magnet description

SM3 coils which were constructed in 1981 for E605 by Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Magnet Description

  • Use existing coils from SM3

    • 3 coil packs:

      191, 163 or 135 inch coils

    • Iron blocks from SM12 (E866) magnet

    • Simulations shown for 191”

  • Suggested by Chuck Brown

191”

135”

Paul E. Reimer


Magnet description1
Magnet Description Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Field simulation for 189” solid Fe magnet (DFG)

  • Use existing coils from SM3

    • 3 coil packs

    • 191, 163 or 135 inch coils

    • Simulations shown for 189”

  • Issues:

    • Target/dump separation

    • Chamber rates

    • Mass Resolution

    • x2 resolution

    • Field simulation

      • no measurements

      • Accurately determine saturation curve

    • Acceptance (i.e. statistical uncertainty at the end of the day)

Paul E. Reimer


Dump target separation
Dump/Target Separation Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Open aperture in red

Solid Fe in Blue

  • Resolution significantly worse

  • Trigger and reconstruction cuts allow for clean separation

    • Remove events with tracks at dump face within 2.25” of beam axis

    • Remove events with tracks greater than 10” from beam axis at targets

  • Recall dump starts at 0”. These cuts effectively remove all events from the front of the dump!!

Target

Dump

Target

Dump

Slight problem from dump J/’s

Paul E. Reimer


Dump target sep solid fe magnet only

Generated Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Dump/Target Sep., Solid Fe Magnet Only

  • Target—solid histograms

    -70 < z < -50

  • Dump—dashed histo.

    0<z

  • Magenta, all events

  • Green: Magneta and

    • xF>0 and

    • M>4.5 GeV

    • and pz>20 GeV

  • Blue: Green and

    • |ytrack|>2.25 in at z=0 (dump face)

  • Red: Blue and

    • |ytrack|<10.0 in at z=-60 (target)

Reconstructed

Paul E. Reimer


Station 1 chamber rates

Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Sta. 1

Station 1 Chamber Rates

Absorber and B Field

Occasionally a muon showers in the absorber

  • If this happens in the center of the absorber, no effect is seen as shower is also absorbed

  • If this happens in the last few inches of the absorber, shower can create extremely large rates in Station 1 (of low momentum particles)

  • Solution is to have an absorber-free region at the end of the field volume and use field as a sweeper

  • In Solid Iron magnet, there is no absorber-free sweeper region! (Can we find a wide gap sweeper magnet?)

  • Requires GEANT MC to see magnitude of effect

Absorber and B Field

Absorber and B Field

B Field only

Paul E. Reimer


Mass resolution
Mass Resolution Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

J/

450 MeV

(and don’t forget about the 0)

J/

470 MeV

(and don’t forget about the 0)

  • Reconstruction of Muon tracks yields virtual photon properties:

    • M2, xF, pT

  • Mass resolution dictates J/ cut

  • Critical for x2 (and x1) resolution

Drell-Yan

Drell-Yan

“Standard” E906 Analysis Mass cut of 4.5 GeV

Paul E. Reimer


Mass calibration
Mass Calibration Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Drell-Yan (M>4.5 GeV) MC in black

J/ MC in red

  • Track reconstruction apparently skews virtual photon mass

  • Events with tracks which significantly miss target have poor mass reconstruction

  • Use known mass (J/) to calibrate this correction

    • Effect is slightly different, but similar to higher mass Drell-Yan

yrtp and yrtn are the reconstructed y offsets of the two tracks at a plane perpendicular to the beam in the center of the target. P and n denote positive and negative.

Mass is the difference between generate and reconstructed mass in the Monte Carlo

Paul E. Reimer


Calibrated mass resolution
Calibrated mass resolution Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

J/

298 MeV

  • Significant improvement near J/

  • General improvement at all masses

Introduces mass offset in Drell-Yan mass range (4.5 < M<8.5 GeV) but better than uncorrected

Drell-Yan

Paul E. Reimer


X f resolution
x Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. SakaiF Resolution

  • No Known xF point to use for calibration.

Paul E. Reimer


X 1 resolution
x Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai1 Resolution

  • x1 resolution worse with correction

Resolution for all x1

Resolution x1≥ 0.75

Paul E. Reimer


X 2 resolution
x Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai2 Resolution

  • Recall D-Y falls exponentially with x2.

  • Events may be reconstructed into neighboring bins.

  • x2 resolution improved by correction.

  • Resolution significantly worse for high x2—is this a problem?

Resolution for all x2

Resolution x2≥ 0.35

Paul E. Reimer


X 2 resolution solid iron and miss reconstruction
x Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai2 resolution—solid iron and miss reconstruction

  • Red events have reconstructed to the correct x2 bin

  • For a significant fraction of the events, x2true is

    one (blue) or

    two (green)

    bins lower than x2recon.

  • Can we live with this misidentification? Or find an additional correction

Essentially no data in this bin

Paul E. Reimer


X 2 resolution open aperture and miss reconstruction
x Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai2 resolution— Open Aperture and miss reconstruction

  • Red events have reconstructed to the correct x2 bin

  • Open aperture design also suffered from misreconstruction, but not as much as solid iron design

  • Does anyone want to look at this in E866 data?

Essentially no data in these bins

Paul E. Reimer


Statistical precision
Statistical Precision Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Increased statistical precision w/Solid Fe Magnet

  • Larger transverse “aperture” in Solid Fe Magnet (34” vs. 25”)

  • Larger Station 3 wire chamber

    • Needed to take advantage of larger aperture

    • Note: open aperture would also benefit from larger station 3

    • Part of Japanese contribution

  • Significant gain in large-x2 region

  • Open Ap. Design may also gain in Stat. as well from larger Station 2 & 3 combination

Paul E. Reimer


Drell yan ratio statistical uncertainty
Drell-Yan Ratio Statistical Uncertainty Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

  • Better Statistical Uncertainty at high x2

  • Crude trigger matrix applied

    • not used in previous plots

    • Accounts for fall-off at low x2 in solid iron magnet

Paul E. Reimer


126 inch magnet
126 inch Magnet Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

  • Resolution in Mass and x2 not better

  • Lower acceptance at high-x2

    • See relative normalization

Mass

All x2

x2 for x2 > 0.35

Paul E. Reimer


Magnet Polarity: Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakaiwhich events do we want?

  • We really want the high-x2 events

  • All the other events come for free

Paul E. Reimer


Magnet polarity 8 gev
Magnet polarity 8 GeV Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Paul E. Reimer


Magnet polarity 6 gev
Magnet Polarity 6 GeV Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Paul E. Reimer


Magent polarity 4 gev
Magent Polarity 4 GeV Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Paul E. Reimer


Magnet polarity 3 gev
Magnet Polarity 3 GeV Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Conclusion

  • Running in opposite polarity may allow smaller chambers

    • Important for Station 3 which is LARGE

    • Acceptance must be verified with Monte Carlo

  • Preliminary Monte Carlo shows resolution is the same (expected)

Paul E. Reimer


Things left to do
Things left to do Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai

Independent verification of results

  • Background rate simulations

    • See GEANT MC talk—this seems to be in hand

  • Opposite Polarity MC with reduced Sta. 3 size

    • I’ve run the MC and could have results next week

  • Resolution improvements with target retrace?

  • Angular resolution for cos 2 distributions

  • Partonic Energy Loss—is x1 resolution good enough?

  • What is the saturation curve of the SM12 iron—this clearly effects the field

    • Some data from Chuck et al. that must be analyzed

Paul E. Reimer


Conclusion solid fe magnet will work always listen to chuck
Conclusion: Solid Fe magnet will work Sumitomo and supervised by KEK and Kyoto. Supervised by Prof. Miyake, Dr. Maki and Dr. Sakai(always listen to Chuck)

Essentially no data in this bin

  • Resolution is poorer with Solid iron magnet, but acceptable?

    • x2 bin resolution

  • Dump/Target separation is achievable

  • Larger aperture provides better statistical precision at high x2

  • Opposite polarity configuration may allow for smaller Station 3 and 4 chambers

Paul E. Reimer


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