A.Seryi, September 30, 2005, page 1

Question on detector solenoid field tail

• In the 2005 field maps, the solenoid field tail at 10m from IP is – about 0.1 T for LDC– about 0.02 T for SiD– about 0.014 T for GLD

• Question: is this field tail real or is it a computational inaccuracy? Especially it looks large for LDC (a kilogauss).

• I discussed this with Brett Parker and his reaction and questions are included in the following list

A.Seryi, September 30, 2005, page 2

Question of field tail, cont.

• If the kilogauss field outside of detector (10m from IP) is real, then– it affects optics and need to be taken into account for design of

coupling corrections, antisolenoids, etc. (see example below)– will be distorted by supports and other magnetic hardware,

giving very complex field pattern outside the detector– may contradict safety rules (affect people outside the detector)– could mean that detector does not have enough iron thickness

and saturates too much at some critical point– we need your estimation on the error of this field value, both

computational and when “environmental” aspects mentioned above will be included

• If this field is not real and is due to computational inaccuracy– then the updated field maps are needed, together with

estimation of inaccuracy

A.Seryi, September 30, 2005, page 3

LDC

LDC fields are from O.Delferrière & O.Napoly, (sent by P.Bambade on Sep 16, 2005)The older TESLA field was scanned and digitized from paper plot (given to me by V.Telnov who got it from someone in DESY)

A.Seryi, September 30, 2005, page 4

SiD

New SiD detector fields: version July 2005, from Bob Wands, FNALOld SD fields from John Hodgson, SLAC, around 1999

A.Seryi, September 30, 2005, page 5

GLD

Fields of GLD detector, version July 2005, from H.Yamaoka, KEK

A.Seryi, September 30, 2005, page 6

Example of optics effectsLDC detector, half_cross_angle=0.007

Fields of LDC, from O.Delferrière & O.Napoly, Sep 16, 2005:L* IP Y(um) Y'(urad) <32> <36> dsigmaY(nm)3.51 -102.93 -112 -187.7477 -55.3231 0.326984.01 -85.636 -106.1 -153.078 -41.8081 0.256914.51 -69.185 -101.3 -123.1995 -31.7753 0.258635.01 -54.177 -97.5 -98.0511 -24.540 0.25215.51 -41.799 -94.7 -77.1936 -18.9556 0.2492

Older TESLA field, scanned and digitized from paper plot (given me by V.Telnov who got it from someone in DESY):L* IP Y(um) Y'(urad) <32> <36> dsigmaY(nm)3.51 -100.88 -110.9 -178.069 -52.7071 0.342384.01 -79.437 -104.5 -133.672 -35.3073 0.267224.51 -58.68 -99.3 -93.8034 -21.6976 0.264365.01 -39.737 -95.3 -60.7074 -12.1953 0.265515.51 -23.762 -92.2 -35.0252 -6.1528 0.26422

Here we show IP angle and position, coupling and vertical dispersion (normalized to nominal beam size) and contribution to the vertical beam size due to SR effects (to be added in quadratures)