A summary on the Hall A cryotarget commissioning:
1) With many people's hard efforts, the cryotarget became operational
on Tursday, Sept. 30, 1997. One loop was filled with liquid hydrogen at
19 K, 26 PSIA, the other loop was filled with liquid deuterium at 22 K,
22 PSIA. Both targets have been in stable operational condition.
2) The cryotarget commissioning started on Wed. Oct. 1. First two and half
days were mostly spent to tune beam into Hall A and carried out part of the
test plan for ion chamber trip level and commissioned the fast raster.
3) On Saturday night (early Sunday morning, Oct.5) we got first beam on
cryotarget. And we quickly ramped up beam to over 120 microA (129 microA)
on our 15cm H2 target (that is almost 700 Watts beam power on target).
The cryotarget took it nicely. Also the ion chamber indicate the Hall
radiation level is low.
4) By 8:00 am Monday, 10/6, we finished hydrogen boiling test. The H2 boiling
test were done with beam energies of 2.445 GeV and 1.645 GeV. Beam energy
was switched from 1.645 GeV to 0.845 GeV and started boiling test for
deuterium. The 15 cm deuteirum target also took up to 120 microA beam
(over 700 Watts of beam power on target). That, as i was told,
is a world record.
5) The deuterium boiling test finished by 10 am Wed. 10/8. Then switched
to parity test setup. However, because beam delivery difficulty, the parity
test did not get any beam. By 7 am Thursday, 10/9. the maintaince period
began, which was the end of the commissioning period.
6) Some preliminary analysis has been done and we have a first boiling result
on dei=uterium for 2 mm raster size. The target density changed by about
4% at 100 microA. This is only an preliminary result, we need to do more
careful analysis to get final results. We also have the spectrometer
extented target acceptance, which is in good agreement in shape with the
simulation result.
Thanks everybody who worked very hard or gave help to make the Hall A
cryotarget a success.
Jian-ping Chen
Run Coordinator
for the Cryotarget Commissioning
Hall A, (757)269-7413