Some beam tuning musings from Fall 2004 runs

David Hertzog

Profiles of unkicked and kicked beam using MuCap setup prior to MuLan run (down kick)

ELog 331

Reminder: extinction plot

• Separator not tuned, first part of kick recenters beam

• Tail indicates new source, not central beam

Airscan study using MuCap ePCs and Tom ELog 344

P = 1.05 PP = 1.04 PP = 1.03 PP = 1.02 PP = 1.01 PP = 1.00 PP = 0.99 PP = 0.98 P

Airscan Key Result: low-momentum sneaky muons ELog 344

• Notable result unrelated to low-side of momentum distribution is in final two entries of table and final two figures. Notice the unkicked vs. kicked stopping distribution of the muons. The unkicked muons, at 1.05P_mu, almost all go through the 75 um window, 250 um muSC, muPC, about 50 cm air (to be measured), and stop in the target. BUT, when kicked, essentially NONE reach the target; the stopping distribution peaks about 20 cm of air before the target. Thus, when we kick, we really do extinguish the "main" muons in our beam and what sneaks through seems to be a source of lower- momentum muons from who-know-where. We need to think about this.

Airscan Key Result: low-momentum sneaky muons ELog 344

No kick (P=1.05 P)

Kick

1.02 P

Setup the beamline first “as it was”

• DAY 1– Install beamline to the normal end

• Should have our best understood focus here from last time• Get direct T0500 to work at rates below 5 MHz

– Make horizontal e decay telescope– Get rate established and general spot

• Careful job of B2/B1 with no SEP on• Careful job of setting SEP-B with 190 kV on• Check kicker with full voltage and establish FOM

“EXTINCTION”

Q8Q9SEPKICKERT1X

S3EMC

T1

Make the momentum sweep here to look for the low-momentum tails

• DAY 2– 90˚ decay rate vs.

momentum sweep of beam

• Thin foil stops narrow momentum bite

Q8Q9SEPKICKERT1X

S3

T1

20-40 m mylar

Beam Tune DACs x fR

ate

Determine if Slit 1 is at all dispersive

• DAY 2– 90˚ decay rate vs.

momentum sweep of beam

• Thin foil stops narrow momentum bite

Q8Q9SEPKICKERT1X

S3

T1

20-40 m mylar

Beam Tune DACs x fR

ate

300

200

100

Find and kill low-momentum “kicked” component

• DAY 3– A variety of changes to

the setup will now take place

– Kicker / Sep swap– Slit 4 upstream of

Kicker

Q8Q9SEPKICKERT1X

S3

T1

20-40 m mylar

Beam Tune DACs x f

Rat

e

Unkicked

Kicked

S3

Slit 4

And lots more, not yet typed up …

Calendar

MTWTWSS

Setup implications for June

• EMC must work reliably from “day 1”– It must be able to be “free mounted” on a stick to move around,

or some other provision to hang it in different places like the SWIC

• Mu decay telescope built with shielding for narrow view – scaler readout implied

• Beam magnet sweeps vs. scaler readout must work• XY Scanner and scintillators a likely option for big-beam

scans (end of kicker, where beam is larger than EMC)• Kicker on in DC mode like we had in tests during

MuCap parasitic time (Anatoly set this up)• HV, other counters, scopes, alignment, .. normal things

MuLan Power

• Francoise full time• David W June 1 – run end• Dave H June 6 – 23• Peter June _6_ - 17th ?• Paul June _6_ - __• Gerco June 6 – 15 ?• Rob June __ - __• Anatoly May __ - ___• Dan tentative if needed

Gerco’s initial polarization calculation

Elog 942 / Analysis

Lots of these plots. Bottom line. Spin points upstream as expected, with perhaps a slight tilt down but within uncertainties we cannot tell for sure

Wild ideas and beamline tests to consider

• Remove Triplet 1 and work in that space• We need parallel beam thru kicker

– Optimize Q8Q9 into EMC (too small?) with/without vac extension.• Could use XY Scanner with two small scintillators

– Do this with/without the two collimator plates in the kicker– Can we use 2 chambers (Johnny chamber + EMC?)– Can we stand the rate here?– We should do this for a full suite of upstream S1/S2 slit sittings

Q8Q9SEPKICKERX

Q8Q9SEPKICKERX vac

EMC collimators