Improved electron beam pipe modelling #691

nat93 · 2024-03-29T21:35:54Z

Briefly, what does this PR introduce?

It contains the improved geometry of the central and far-backward beam pipes. In addition, some overlaps between ePIC and the new beam pipe are fixed by changing the detector components' inner radius (this has to be approved by detector experts).

What kind of change does this PR introduce?

Bug fix (issue #__)
New feature (issue #__)
Documentation update
Other: __

Please check if this PR fulfills the following:

Tests for the changes have been added (could be checked by plotting the entire geometry, e.g., through 'dd_web_display,' or material scan, e.g., through 'g4MaterialScan_to_csv')
Documentation has been added/updated (comments were added)
Changes have been communicated to collaborators (partially, the Vacuum and Background groups approved the changes)

Does this PR introduce breaking changes? What changes might users need to make to their code?

We must check how the modified subsystem geometries affect detector performance (angular acceptance, resolution, etc.).

Does this PR change default behavior?

Yes. Now, we should have a more accurate beam pipe with an enlarged inner radius of subsystems in the forward direction to fit the new beam pipe. This may affect detector background rates.

Things to be done

Still, the materials of the beam pipes (by default, aluminum) are wrong, except for the IP beam pipe. The next step would be to fix this issue (it should be stainless steel with a copper coating).

References

Machine lattice file v6.2: esr-ring-norad.tfs and esr-survey-doug.tfs
Electron beam pipe vacuum geometry (from the EIC vacuum group): detector_chamber_211004.pdf and STL file
Detector geometry file - Apr 2024: EPIC Envelope - 04-03-2024.pdf
Updated detector geometry table - Apr 2024: Detector-20240426

…odified detectors to fit the outgoing h-beam pipe

…ard sub-systems to fit the outgoing h-beam pipe (cone-shape). Rebuilt magnets. Some geometry parameters are hard-coded (should be fixed).

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veprbl · 2024-04-01T06:38:17Z

compact/far_backward/lumi/exit_window.xml

+      <id>system:8</id>
+    </readout>
+  </readouts>
+


Not sure if this is supposed to go into the official geometry. Why do we need this?

Hi @veprbl ,
Thanks for your comment. The motivation for making the luminosity monitor exit window sensitive to radiation is that we have to study this element (a simple aluminum block) and check if it will survive under a high flux of synchrotron radiation photons. So far, the preliminary study showed that at 18 GeV, 0.227 A electron beam, the window will melt in 2 hours. So, we have to think about additional cooling. Therefore, I would suggest keeping this part of the code to collect deposited energy in that element.
What do you think?

…c_sr_background_study Merge

wdconinc

Thanks for this PR. That's a lot of great work that we should work to include in the epic geometry for one of the next campaigns. I have left some comments. Mainly, please coordinate with @ajentsch in the context of #665 to make sure there is no duplication of efforts.

wdconinc · 2024-04-01T15:20:22Z

src/magnetVacuumFF.cpp

@@ -144,7 +144,7 @@ static Ref_t create_detector(Detector& det, xml_h e, SensitiveDetector /* sens *
    // -->the volume will be calculated at the end
    //-------------------------------------------

-    double endOfCentralBeamPipe_z = 445.580*dd4hep::cm; //extracted from central_beampipe.xml, line 64
+    double endOfCentralBeamPipe_z = 560.00*dd4hep::cm; // <-- extracted from central_beampipe.xml


Can we get this from the geometry instead of copying the value and hardcoding it? (I know, not your fault it was already hardcoded, but might as well fix it while we're at it. Also, maybe this should be done in #665.)

To avoid overlap with what @ajentsch has already done in that PR #665, please coordinate with him.

This should be fine. That's the one part of my magnet volume code which is done that way since we didn't have the numbers somewhere to be grabbed dynamically. @nat93 can you add the change to magnetVacuumFF.cpp to grab the number from line 147 from the central_beampipe.xml line 43?

Hi @ajentsch and @wdconinc , thanks for your comments. Yes, I will fix it, following Alex's suggestion.

wdconinc · 2024-04-01T15:21:57Z

compact/far_backward/magnets.xml

-      <pipe id="0" name="Pipe_to_Q1eR"
-        xcenter="0" zcenter="(Center_Beampipe_End + Q1eR_CenterPosition+Q1eR_Length/2)/2"
-        length="Center_Beampipe_End - (Q1eR_CenterPosition+Q1eR_Length/2)" theta="0"
-        rout1="Center_Beampipe_Rad" rout2="Q1eR_InnerRadius">
+      <pipe id="0" name="Pipe_0"
+        xcenter="0" zcenter="-7342.0 * mm + (Center_Beampipe_End + 7342.0 * mm)/2"
+        length="Center_Beampipe_End + 7342.0 * mm" theta="0"
+        rout1="Center_Beampipe_Rad" rout2="(111.40/2 + 2) * mm">


We should avoid changing parametrized values into hard-coded values that are then used in multiple places. (Applies file-wide.)

It is true. However, I would suggest keeping the beam pipe geometry separated from the magnet geometry because they have different sources (i.e., the beam pipe model is from the vacuum and background groups, magnets -- lattice and magnet groups). Also, the inner radius of magnets should not always follow the beam pipe radius.
I can create beam pipe global variables in the central-beam pipe XML file to be used here. What do you think @wdconinc ?

I am not sure if we need them all as global variables in the central beam pipe; they can be local variables in the far_backward and far_forward sections, right?

wdconinc · 2024-04-01T15:23:27Z

compact/far_backward/definitions.xml

+    <constant name="B2BeR_Length"         value="5.500075391030 * m"/>
+    <constant name="B2BeR_CenterPosition" value="-15.000075390000 * m + B2BeR_Length/2"/>


Do the microns matter here?

Suggested change

<constant name="B2BeR_Length" value="5.500075391030 * m"/>

<constant name="B2BeR_CenterPosition" value="-15.000075390000 * m + B2BeR_Length/2"/>

<constant name="B2BeR_Length" value="5.5 * m"/>

<constant name="B2BeR_CenterPosition" value="-15.0 * m + B2BeR_Length/2"/>

Here, I simply follow the lattice file v6.2.

If we are following a specific lattice version, we should mention this in one of the comments somewhere, with a reference for where one can find this lattice version (even if not publicly accessible).

wdconinc · 2024-04-01T15:24:54Z

compact/definitions.xml

-    <constant name="ForwardRICHRegion_tan1"        value="CentralTrackingRegionP_tan * 0.88" />
-    <constant name="ForwardRICHRegion_tan2"        value="Eta3_6_tan * 0.89" />
+    <constant name="ForwardRICHRegion_tan1"        value="CentralTrackingRegionP_tan * 1.20" />
+    <constant name="ForwardRICHRegion_tan2"        value="Eta3_6_tan * 1.20" />


This changes the shape of the dRICH and can't get merged without TIC review and approval.

Could you please ping the relevant experts? Because we cannot use the actual beam pipe due to overlaps with dRICH.

wdconinc · 2024-04-01T15:26:10Z

compact/central_beampipe.xml

-          <zplane z="BeampipeDownstreamStraightLength" OD="BeampipeOD"/>
-          <zplane z="4484.25 * mm" OD="BeampipeOD"/>
+          <zplane_vac z="670.00 * mm" OD="60.00 * mm"/>
+          <zplane_vac z="755.00 * mm" OD="60.00 * mm"/>
+          <zplane_vac z="755.00 * mm" OD="62.00 * mm"/>
+          <zplane_vac z="4300.00 * mm" OD="62.00 * mm"/>
+          <zplane_vac z="4450.00 * mm" OD="44.00 * mm"/>
+          <zplane_vac z="4460.00 * mm" OD="44.00 * mm"/>
+          <zplane_vac z="4660.00 * mm" OD="54.00 * mm"/>
+          <zplane_vac z="5100.00 * mm" OD="54.00 * mm"/>
+
+          <zplane_mat z="670.00 * mm" OD="(62.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="(670.00 + 1.0) * mm" OD="(62.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="(670.00 + 1.0) * mm" OD="(60.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="(755.00 - 1.0) * mm" OD="(60.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="(755.00 - 1.0) * mm" OD="(62.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="4300.00 * mm" OD="(62.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="4450.00 * mm" OD="(44.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="4460.00 * mm" OD="(44.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="4660.00 * mm" OD="(54.00 + 1.0 * 2) * mm"/>
+          <zplane_mat z="5100.00 * mm" OD="(54.00 + 1.0 * 2) * mm"/>


I don't really like the duplication of all z and many of the OD values here. Can we approach this conceptually different so it doesn't require this level of duplication?

This now also adds another methodology to define beampipes: we can still use <zplane> but now we have <zplane_mat> and <zplane_vac>. We may want to have one way, which sensibly defaults back to the previous behavior.

OK. Thanks. I will think about this.

compact/far_backward/magnets.xml

wdconinc · 2024-04-01T15:34:47Z

src/IP6BeamPipe.cpp

@@ -201,6 +233,121 @@ static Ref_t create_detector(Detector& det, xml_h e, SensitiveDetector /* sens *
    return std::make_pair<Volume, Volume>({"v_" + name + "_matter", matter, m_Al},
                                          {"v_" + name + "_vacuum", vacuum, m_Vacuum});
  };
+  //---------------------------------------------------------------------------------
+  // Create downstream volumes
+  auto create_volumes_2 = [&](const std::string& name, xml::Component& x_pipe1, xml::Component& x_pipe2,


We should not duplicate the API here, but make the original one work reliably in both use cases. This code duplication doubles maintenance burden.

OK. I will try to merge them.

wdconinc · 2024-04-01T15:35:09Z

src/IP6BeamPipe.cpp

+  //  _________/......
+  //  ................
+
+  auto zplane_to_polycones_2 = [](xml::Component& x_pipe) {


We should not duplicate the API here, but make the original one work reliably in both use cases. This code duplication doubles maintenance burden.

OK. I will try to merge them.

wdconinc · 2024-04-01T15:36:37Z

compact/tracking/definitions_craterlake.xml

-    <constant name="ForwardTOFRegion_minR"        value="8*cm" />
+    <constant name="ForwardTOFRegion_minR"        value="10*cm" />


Changes to detector envelope volumes require updates to the detector parameter table first, along with TIC review and approval (https://eic.jlab.org/Geometry/Detector/Detector-20240117135224.html indicates 8 cm).

As I wrote, we cannot fit the actual beam pipe in the current detector. Please let me know the procedure to get it approved. Do you know who should be contacted?

The current procedure is to send an email with requests for changes to the detector parameter table to the detector parameter table maintainers, the project's experiment contacts, collaboration leadership, and the specific detector contacts. I will send you their emails instead of posting them here.

wdconinc · 2024-04-01T15:38:11Z

compact/tracking/definitions_craterlake.xml

-    <constant name="ForwardMPGDMod1_rmin"         value="7.014*cm" />
-    <constant name="ForwardMPGDMod2_rmin"         value="7.014*cm"/>
+    <constant name="ForwardMPGDMod1_rmin"         value="8.014*cm" />
+    <constant name="ForwardMPGDMod2_rmin"         value="9.014*cm"/>


Changes to detector envelope volumes require updates to the detector parameter table first, along with TIC review and approval.

…stead of hardcoding in src/magnetVacuumFF.cpp

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…in compact/far_backward/definitions.xml

…c_sr_background_study Pull from the main branch

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…nts for the central beam pipe.

…c_sr_background_study integrate the remote changes

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…c_sr_background_study integrate the remote changes

… and B2BeR)

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… 4.4 m

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…m pipes

…c_sr_background_study Merge from git before push

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wdconinc · 2024-05-07T17:24:27Z

Formatted, merged main, conflicts resolved in favor of feature branch.

natochii and others added 10 commits March 22, 2024 03:48

Private changes as on March 19, 2024 - improved beam pipe, slightly m…

696eb3b

…odified detectors to fit the outgoing h-beam pipe

Improved Central and Far-Backward beam pipes. Enlarged R_min for forw…

61ab792

…ard sub-systems to fit the outgoing h-beam pipe (cone-shape). Rebuilt magnets. Some geometry parameters are hard-coded (should be fixed).

Fixed a typo

cccf439

Change Lumi Exit window to Calorimeter

aa8f64e

Make Lumi Exit Window sensetive

f3c86ec

temp modify .gitignore

44c6d17

Changes before merging with the main branch

d2ac0b1

Forgotten changes

b18c8d6

Described the corrected central beam pipe through XML parameters

d035b34

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github-actions bot added topic: infrastructure Regarding build system, CI, CD topic: tracking topic: far-forward Deterctors for small-angle particles topic: far-backward topic: magnets labels Mar 29, 2024

revert development byproduct changes

490c56c

veprbl force-pushed the eic_sr_background_study branch from 9a507a8 to 490c56c Compare April 1, 2024 06:34

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natochii added 2 commits April 1, 2024 23:33

Fix overlaps between DRICH and BeamPipe_assembly

9b7415a

Merge branch 'eic_sr_background_study' of github.com:eic/epic into ei…

f9adaf8

…c_sr_background_study Merge

wdconinc reviewed Apr 1, 2024

View reviewed changes

natochii and others added 9 commits April 2, 2024 03:23

Get the end of the central beam pipe for hadrons from the XML file in…

82db90b

…stead of hardcoding in src/magnetVacuumFF.cpp

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Define backward electron beam pipe parameters as a list of constants …

8427111

…in compact/far_backward/definitions.xml

Merge branch 'eic_sr_background_study' of github.com:eic/epic into ei…

2d99a6d

…c_sr_background_study Pull from the main branch

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Avoid duplication the API in src/IP6BeamPipe.cpp. Added global consta…

857c7d8

…nts for the central beam pipe.

Merge branch 'eic_sr_background_study' of github.com:eic/epic into ei…

63c4bfc

…c_sr_background_study integrate the remote changes

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Avoid duplication of the same beam pipe parameters (e.g., Z or OD)

2bb7f3c

natochii and others added 22 commits April 2, 2024 07:46

Avoid duplication of the same beam pipe parameters (e.g., Z or OD)

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Avoid duplication the API in src/IP6BeamPipe.cpp

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minor typo fixing

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Merge branch 'eic_sr_background_study' of github.com:eic/epic into ei…

938fe24

…c_sr_background_study integrate the remote changes

Modified far-backward beam pipe materials

ec69b1b

Added coating and changed materials for backward magnets (Q1eR, Q2eR,…

2b88eac

… and B2BeR)

Corrected central beam pipe aperture

cb400ed

Added coating to the central beam pipe

48fd46d

Fixed beam pipe volume subtraction logic

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Added SR mask-5 to avoid SR reflectio nfrom the flat beam pipe tip at…

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… 4.4 m

Merge and pull

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fixed strange git symbols

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Updated FWD TOF tracker according to the latest detector numbers

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Updated FWD MPGD tracker according to the latest detector numbers

28b2477

Added an upstream lepton-hadron joint between the backward and ip bea…

d6eca3f

…m pipes

Merge branch 'eic_sr_background_study' of github.com:eic/epic into ei…

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Improved electron beam pipe modelling #691

Improved electron beam pipe modelling #691

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wdconinc commented May 7, 2024

		<constant name="B2BeR_Length" value="5.500075391030 * m"/>
		<constant name="B2BeR_CenterPosition" value="-15.000075390000 * m + B2BeR_Length/2"/>

		<constant name="ForwardTOFRegion_minR" value="8*cm" />
		<constant name="ForwardTOFRegion_minR" value="10*cm" />

Improved electron beam pipe modelling #691

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Improved electron beam pipe modelling #691

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nat93 commented Mar 29, 2024 • edited

Briefly, what does this PR introduce?

What kind of change does this PR introduce?

Please check if this PR fulfills the following:

Does this PR introduce breaking changes? What changes might users need to make to their code?

Does this PR change default behavior?

Things to be done

References

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nat93 Apr 1, 2024 • edited

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wdconinc commented May 7, 2024

nat93 commented Mar 29, 2024 •

edited

nat93 Apr 1, 2024 •

edited