Feature #1551
Lithium Hydride material
100%
Description
Require Lithium Hydride for MICE absorbers...
Files
Updated by Rogers, Chris over 8 years ago
- File TIO_FERMI2.pdf TIO_FERMI2.pdf added
By email:
Note chemical analysis is TIO_FERMI2.pdf
Chris, I have attached the chem analysis of our LiH. Alan Alan Bross (630) 840-4880 (Office) (630) 667-3061 (Cell) (630) 840-3061 (FAX) From: "chris.rogers@stfc.ac.uk" <chris.rogers@stfc.ac.uk> Date: Wednesday, September 17, 2014 at 10:21 AM To: Alan Bross <bross@fnal.gov>, Victoria Blackmore <V.Blackmore1@PHYSICS.OX.AC.UK>, Ken Long <K.Long@imperial.ac.uk> Cc: Pavel Snopok <snopok@gmail.com>, Daniel Kaplan <kaplan@iit.edu>, Christopher Hunt <christopher.hunt08@imperial.ac.uk>, Jaroslaw Pasternak <j.pasternak@imperial.ac.uk>, Mark Palmer <mapalmer@fnal.gov>, Maura Barone <maura@fnal.gov>, Jean-Baptiste Lagrange <j.lagrange@imperial.ac.uk>, Gene Kafka <gtkafka@gmail.com> Subject: Re: LiH density? (HIGH PRIORITY) It's my fault, I knew about it but did not implement this. I added the Lithium Hydride as a MICE material to the MAUS trunk, as MICE_LITHIUM_HYRDIDE. I set density to 0.69 g/cm^3, assume mass fractions are as per pdg (Li:0.126797, H:0.873203) and use the Geant4 default isotopic abundance for e.g. Lithium. Let me know if you have a better specification. A technical note would be ideal. The usual test suite is running... Cheers, Chris On 17/09/14 15:57, Alan D Bross wrote: Victoria et al., For the purposes of our simulations, the LiH density should be set at 0.69 g/cm^^3. That is what has been measured for the disk that we will use in the experiment. The disk was x-ray’d and is uniform in density (no voids). The other disks in Gene’s report (*Gene is* *it a MICE note yet?)* where small sample disks that came from a different mold and press. Dan is correct - this material is made via hot-isotastic pressing. If I remember correctly, the spec there is 150C and 750 psig, but I will have to look that up. I have found various numbers for the “intrinsic” density of LiH (.76-.82). We should not use the PDG number. One thing that worries me now, it that Y12 always claimed that their material reached 98% of the intrinsic property of LiH. The density of the MICE disk seems to fall outside that spec. It does not really matter for MICE, but we may be procuring additional disks from them. Regards, Alan Alan Bross (630) 840-4880 (Office) (630) 667-3061 (Cell) (630) 840-3061 (FAX)
Updated by Rogers, Chris over 8 years ago
Some stuff committed as r772 - will wait on Bross for relative abundance of Li vs H...
Updated by Rogers, Chris over 8 years ago
A quick check indicates that the simulation is producing the same output. Needs some detailed cross checks that the material is really doing the right thing.
Updated by Rogers, Chris over 8 years ago
Jaroslaw asked me to make a patch file that Chris Hunt could install in his version of MAUS with minimum hassle.
The following should do it:
cd ${MAUS_ROOT_DIR} wget http://micewww.pp.rl.ac.uk/attachments/2549/LiH.patch patch -p0 < LiH.patch make
Let me know if there is a problem. Checked against latest trunk. I am running some physics checks now - to check how much the LiH model has moved.
Updated by Rogers, Chris over 8 years ago
- File energy_loss.png energy_loss.png added
- File px.png px.png added
I got a complaint from Chris Hunt that the energy loss was rather large. I note that MAUS reports the density is correctly update (Geant4 calculates the mass of material in ratio new_mass/old_mass = 0.8414634146341463 = 0.69/0.82
.
I tried tracking through 65 mm cylinder of LiH, output px distribution and energy distribution as below:
Energy loss is indeed coming through rather large. I have no feel for what is correct.
Updated by Rogers, Chris over 8 years ago
- File px_v2.png px_v2.png added
- File energy_loss_v2.png energy_loss_v2.png added
- File LiH_2.patch LiH_2.patch added
By email, from Chris Hunt:
Hi Chris, Just had a read through the patch you sent - should the numbers in the lines: miceLiH->AddElement(elMiceLi, 0.126797); - and - miceLiH->AddElement(elH, 0.873203); both be equal to 1? It looks like the other functions add elements according to the their fraction in the molecular formula. I'm not actually sure what numbers you've used there? Cheers Chris
This is the mass fraction of Lithium to Hydrogen in Lithium Hydride material
http://pdg.lbl.gov/2014/AtomicNuclearProperties/HTML/lithium_hydride_LiH.html
The function call is
// // Add an element or material, giving fraction of mass // void AddElement (G4Element* element , //the element G4double fraction); //fractionOfMass
I note there is also
// // Add an element, giving number of atoms // void AddElement(G4Element* element, //the element G4int nAtoms); //nb of atoms in // a molecule
Might make more sense because presumably the mass fraction will change with odd isotopes? I gave it a go, the results look more sane...
Updated by Rogers, Chris almost 8 years ago
- Status changed from Open to Closed
- % Done changed from 0 to 100
I think this is okay now