From New IAC Wiki
Jump to navigation Jump to search


Met with IAC director Doug Wells and Khalid Chouffani at the IAC to determine the next steps on the positron project funded by DOE.

1.) Ask Mark Balzer to submit a report on the radiation dose measurements taken.

2.) Once report is digested, determine the HRRL shielding needed to move the accelerator to the wall as shown in Stancari's design.

3.) Doug will send a paper with gamma measurements made that may be comparable to the HRLL.

4.) Compose a downtime schedule for the HRRL

5.) Try to get Yag crystals from JLab for the flags and see if there are any beam profile monitors available.

6.) The Bevatron at LBL may be decomission. see if they will ship lead shielding.

12/17/09 11 am at IAC

Met with Khalid and Sadike to discuss progress

1.) Sadiq has been able to run Optim32 and is starting to figure out the beam parameters and their meaning.

2.) Sadiq will create a geometry file in GEANT4 which represent the HRRL accelerator room. The goal will be to simulate the expected particle flux change as seen at the exit of the accelerator room after we move the cavity to the wall. The first goal will be to simply look at the ratio of particle fluxes before and after the move.


3.) Khalid is still waiting for final quotes and specification on the FC from the vendor.

12/23/09 10 am at IAC

1.) Khalid will order FC ($1k) and ask for a second one. Princeton scientific

2.) Sadiq has a geometry file for the HRRL, and a definition of concrete, and has set up the original electron source.

3.) Next

a.) Sadiq will set up the moved electron source (done)

b.) Create gaussian beam [math]\sigma[/math] = 3 mm (done)

c.) Physics list for electron, gammas (done)

d.) upload a physics event for each of the interactions in your physics list illustrating electron and photon interactions with the target and the walls. (done)

4.) Next meeting week of Jan 11., prefferably thursday.

5.) Check drawings with Denton Dance x4710, specifically the ceiling thickness, distance from outside wall to grass, check wall thicknesses, are wall all concrete or do they have dirt cores (need to upload electronic version of architectural design)


Fogot to write notes on this meeting


1.) Simulation Status (Radiation ratio before and after move)

2.) YaG viewers: Khalid inspects YaG material.

3.) Parts Inventory: We need to start collecting parts (magnets , power supplies, ...) so we can determine what equipment needs to be ordered.

Power supplies have a 6 week lead time.

Want to be ready to install parts by July.

March 10: Goal working powers supplies + all quads at the IAC (Mapping begin or order correct power supplies)


1.) Simulation Status (Radiation ratio before and after move)

Record Step Number and unique particle number.
Contour plots of photon, electron, and neutron at entrance to volume 8  (particle flux through the hallway).
Then plot energy profile of the hot spots.

2.) YaG viewers: Khalid inspects YaG material.

The ones from JLab have no lines for size .

Its $2k for a YaG with imprinted and calibrated cross hairs with 5 mm radius circle outside beam size.

3.) Parts Inventory: We need to start collecting parts (magnets , power supplies, ...) so we can determine what equipment needs to be ordered.

All Quads and Kiwi dipoles are in Physics Beams lab.

Check if the dipoles have vacuum chamber

We have 7 power supplies working.

Get 6 more power supplies

Power supplies have a 6 week lead time.

Want to be ready to install parts by July.

March 10: Goal working powers supplies + all quads at the IAC (Mapping begin or order correct power supplies)


1.) Plot curves at 10 MeV HRRL energy of the expected does at detector 17 as a function of beam current before and after the move. Include uncertainties.

Assume a linear dependence and perform a fit. Errors in parameters, p_value, and Probability you are correct/wrong

2.) Khalid has order 1 Yag crystal and a filter set.

3.) Sadiq has 13 magnets with working power supplies requiring 4kW of power at full current but we only need 1/10 of that to control a 10 MeV beam so require 400 Watts.

Sadiq will check Chads power calculation.

4.) Sadiq and Khalid will map 2 quads June 2 - 11.

5.) Collect beamline parts for the emittance measurement.

Longest pipe possible after the YaG flag. Need to attach FC thats in Forest's office.

Need to install water cooling for the FC

collect pipe for upstream of the Yag Flag. watch the quad pole gap.

Coordinate everything with Chad/Kevin.

YaG filter arrive July 8. Target date for emittance measurement is July 26-July 30.

Must begin constructing magnet stands by July 5 assuuming 2 weeks to build and 1 week to align. Stands for 2 Quads, 1 FC, and YaG infrastructure.

By June 2 have a beamline layed out for emittance test.

6.) Run simulation on Brems for several different lead cylinder thicknesses according to the lead pieces in the HRRL.


Meeting at Physics to discuss HRRL

Doug' Agenda

1) Bremsstrahlung end-station (polarized and unpolarized) - must be readily interchangable with the positron end-station.

Dan Dale will be consulted to determine the location of a bremsstrahlung target. The quads on the 90 degree line may need to be moved closer together if Dan Dale requires that the target be located about 2m before the wall to the experimental cell.

2) Electron beam optics must enable high transmission to bremsstrahlung end-station when we are running in electron mode.

Id was decided to look into purchasing a FC which will be insertable on the 90 degree line in order to assist in the beam line turning and go beyond the maximize transmission experienced by Dr. Hunt.

3) Alignment and vacuum boxes on 45-degree magnets. Do the vacuum boxes have to be rebuilt? Does the gun need to be taken off?

It was decided that John ellis will design vacuum boxes for the kiwi dipole that have larger beam pipe inlets and outlets to help with transmission. An outside vendor may be used to built them.

The Gun will be removed for alignment using a procedure from Khalid.

4) Full, permanent beam optics, steering, inserts parameters completely set so John can put together a final design. Is everyone on the same page?

John Ellis has the dimensions of all components and Yujong will confirm that they are in the correct locations. Stands will be fixed to the floor and some flanges will be constrained.

5) Water-cooled W-target in vacuum - is this necessary? How do we protect vacuum systems, the gun, etc.? How do we design to minimize potential for failure?

A gate valve was deemed to be too slow to risk water contamination of the HRRL gun. Alternative target designs will be pursued. Nitrogen was an acceptable coolant inside the vacuum and may be used.

John Ellis will design a vacuum chamber for a tungsten target.

HRRL team issues

1.) HRRL beam stability. The beam spot was moving intermittently in the beam left-right direction during the last round of emittance measurements. The jitter became less as the energy was increased from 11 MeV up to 16 MeV.

2.) A request was made to improve the ability to adjust the position of beam line magnets. The current system is good but the desired improvements need to be identified. Some options were discussed but the conclusion was to leave the system as it is now until the alignment has identified what needs to be changed.

3.) We need higher current power supplies for the quads. Yujong will look into how high they should go.

Go back to Positrons