Magnet Microwaves Target Ammonia UVASLACJLAB Target Magnet After SANE and operation over 20 years in sometimes extreme conditions magnet returned to Oxford Instruments for retuning Diagnosis was that magnet had become unstable over the years because of relaxation of the clamping of th ID: 379496
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Slide1
Polarized Target “Issues”
Magnet
Microwaves
Target AmmoniaSlide2
UVA/SLAC/JLAB TargetSlide3
MagnetSlide4
After SANE, and operation over 20 years in sometimes extreme conditions, magnet returned to Oxford Instruments for
retuning.
Diagnosis was that magnet had become unstable over the years because of relaxation of the clamping of the coils.
At Oxford Instr. Coils reclamped to original specifications.
Magnet retested: 1) Ramped at higher than original specified rate to 5.1 T
Quenched after 15
mins
in persistent mode
( training quench)Slide5
2) Ramped at specified rate to 5.0 T
Stayed at field in persistent mode for 105
minutes before ramping down3) Ramped to 5.1 T at same rate as Test 1
Stayed at field for 105 minutes in persistent mode before ramping down.
Ready to operate again in extreme conditions.Slide6
Microwaves
140 GHz/5 T EIO – have several
NH3 Polarization > 90%70 GHz/2.5 T Carcinotron (have several) or EIO
(borrow one from Duke University). EIO has higher power output than Carcinotron.
Polarization ~40%
Changing EIOs easiest to do – use same
power supply. Slide7
Microwaves (contd.)
Microwave guides at 70GHz. (
Have at UVA)
Frequency and power read-outs at 70 GHz (Have at UVA )EIO power supplies ~ four, between UVA and
JLabCarcinotron Power supplies:
one at UVA, one somewhere in Germany on way to UVA Slide8
NMR
Have all the necessary equipment, many Q –meters, several signal generators and power supplies.
Only need to retune system at 106.5 MHz (2.5 T) from 213 MHz (5 T)Slide9
Ammonia Targets
All the polarized material will be irradiated ammonia (
14
NH3).Slide10
Ammonia Targets (contd.)
Ammonia irradiated at the MIRF facility at NIST
Use 19
MeV electrons at 10 – 15 μAIrradiate to the level of ~
1017 e-
.cm
-2
One
irrad
. Load ~ 2.5 target loads
Need ~ 18 target loadsSlide11
Ammonia Targets (contd.)
Current inventory: ~
16
target loads – checking further.Unirradiated inventory: 3 target loads – checking further
Previously used material: ????Next irradiation (probably June)Last Irradiation: October 2009Slide12Slide13
NH3
(2
nd
Batch)Slide14
Participation
Faculty Level
Don Crabb, Donal
Day, Oscar RondonPost Docs
Hovannes
Baghdasaryan
,
Narbe
Kalantarians
Jonathan Mulholland?
Students
“
Stache
”
Kvaltine
,
Zihong
Ji
, Mikhail
Yurov