Main Injector Lambertson Aperture Scans David Johnson and Ming-Jen Yang March 17, 2006

Motivation and Data Collection The goal is to document the loss free apertures through the Main Injector Lambertson regions prior to the installation of the WQB wide aperture quads. The expected increase in circulating beam aperture in the Lambertson regions is due to: –the increase in beam pipe dimensions of the WQB on the inside of the ring, –the shifting of the Lambertson septa to the radial outside (which will also require new Lambertson flanges and the re-alignment of the upstream end of the transfer line. The wide aperture quad (4”) will allow the extracted beam to be farther to the outside of the ring without loss on the quad pole tip.

LM520A (61-0) LN520B (61-1)LN520C (61-2/2)* LN520D (61-3/4)* LN520E (61-45)* LM521A (61-5) LN521B (61-6/6) * LN522A (61-7/7)* LM522B(61-8) LM522C(61-9) LM522D (61-10) LM522E (61-11) LM522F (62-0) LM522G (62-1) LM522H (62-2) Q523 Q522 Q521 Q520 Q522 Q521 V701Q701LAM52CLAM52B LAM52A ES52BES52AK520A,B LM701 (P1) H522 TAR521 *Goes to chassis 2 w / beamline integrators – reset / hold timers I:LMNUMR and I:LMNUMH The numbers in parenthesis are the house - slot number and the number after the “/” is the slot in crate 2 LM523 (62-3) MI-52 Loss Monitor Placement

LM607A(63-7) LM607B(63-8) LM608A(63-9) LM608 B(63-10) LM608 C(63-11) LM608 D(64-0) LM608 E(64-1) LM608 F(64-2) LM608 G(64-3) LM608 H(64-4) Q609 Q608 Q607 Q608 V101Q101LAM60CLAM60B LAM60AH608RF cavities MI-60 Loss Monitor Placement Around NuMI Lambertsons LM on Lambertson Flange LM on conduit LAM60 LMQ608 LAM61A LAM60 – NuMI Loss Monitors LAM61B V100 Q101 LM609(64-5)

Q620 Q619 V101Q101LAM60CLAM60B MI-62 Loss Monitor Placement LM619B (64-4) Q620 LAM60A H620 Q621 LM619C (64-5) LM619D (64-6) LM619E (64-7) LM619F (64-8) LM620A (64-9) LM620B (64-10) LM620C (64-11) LM620D(65-0) LM621 (65-1) LM619A (64-3) pbars

Data Collection Injection scans were performed using a dedicated 8 GeV $2E cycle. Extraction scans (MI52 and MI60) were performed on low intensity stacking and NuMI cycles. First turn data was taken by aborting the beam after only one pass thru the Lambertson region of interest. The loss monitor “sample and hold” event, $2C, was set to measure the peak of the loss monitor response. Data on beam intensity, positions, loss and magnet currents were taken using I90. Data was transferred to excel for data analysis

Expectations What apertures are expected through Lambertsons? –Field Free: 60 mm loss free (1/2 MI beam pipe if septum edge is located on MI centerline) –Field Region: 50 mm loss free (on axis) due to 50 mm field region aperture. Expect first loss on outside of ring to occur on the Lambertsons either side of the quad What aperture is expected vertically in MI beam pipe? –The inside dimension of MI beam pipe is ~47mm For 20  and  = 55m, 6  = 26.4 mm => +/-10.3mm free aperture

Summary of Aperture Scan Data Sets MI40 8 Gev –Horizontal scan Field and Field Free region with 1 st turn H402:3 –Vertical scan of Field Free close to notch (V401:4) –Horizontal scan of Field region (only toward septum) K400 MI52 8 Gev –Horizontal scan Field region with 1 st turn KPS5S –Horizontal scan Field Free circulating using H522:3 –Horizontal scan Field Free and Field region 1 st turn using H522:3 MI Gev –Horizontal scan Field Free region using H522:3 –Vertical scan of Field Free region using V521:4 –Horizontal scan of Field region using KPS5S and H522:3 MI60 8 Gev –Horizontal scan Field Free region 1 st turn H608:3 –Horizontal scan Field Free (and Field) region 1 st turnH608:3 MI Gev –Horizontal scan Field region KPS6S –Horizontal scan of Field Free region (only toward septum) circulating H608:3 MI62 8 Gev –Horizontal scan Field Free (and Field) region 1 st turn H620:3

Summary of LAM40 Scan Assume 10  beam 8 Gev First turn using protons (060201) –Field Free Region Centroid of 8 Gev beam at HP402 is mm Inside loss start mm on HP402 as seen on LM402G Loss on septum starts at -11 on HP402 or mm motion from the nominal Loss free aperture ~30 mm+ 16mm beam size -> ~46 mm –Field Region Beam strikes loss monitors LM402F,G,and H septum first on both sides of the field region The edge of loss free region based upon the upstream loss monitors is 33.6 and 57.6 which gives a width of 24 mm + beam width which would eb ~ 40 mm

LAM40 First Turn Scan

MI40 Position Calibrations

Summary of LAM52 Scans Assume 10  beam,then 6  would be ~16 mm at entrance to 1 st Lambertson Calculate aperture relative to position at entrance to first Lambertson HP_LAM52A 8 Gev First turn Field Free (060130) –Centroid of 8 Gev beam is mm at LAM52A –Inside loss start -44 mm on beam pipe –Outside loss starts -6 mm on septum –Loss free aperture 38 mm + beam size (~16mm)-> ~ 54 mm 8 Gev Circulating Field Free (060131) –Inside loss starts at -39 mm –Outside loss (septum) first loss -12 mm –Loss free aperture 24 mm + beam size (~16mm) -> ~40 mm 120 Gev Field Free(060223) –Centroid circulating beam -13 mm –First loss seen on LM522A at mm –No loss seen on inside beam pipe –Vertical scan

Aperture of LAM62C 8 Gev 1 st Turn

LAM52 Field Free 8 GeV First Turn Aperture

LAM52 Field Free 8 GeV Circulating Aperture

Lam52 8 Gev Field Region

Summary of LAM60 Scans Assume 10  beam 8 Gev First turn Field Free (060130) – Centroid of 8 Gev beam is -32 mm –Inside loss start -46 mm beam pipe –Outside loss starts -14 mm on septum as seen by LM608F –Loss free aperture 24mm+beam size -> ~37mm 8 Gev First Turn Field Free (060131) –Inside loss starts at -40 mm –Outside loss (septum) first loss -18 mm –Loss free aperture17mm+beam size (~16mm) -> ~34mm 120 Gev Field Free and Extraction (060223) –Centroid circulating beam -23 mm –First loss seen at -3 mm –Centroid of extracted beam mm –First loss seen on LM608A at 11.4 mm

LAM608 8 GeV 1 st Turn Beam Aperture Scan

Trajectory thru LAM60

LAM Gev Field Region Scan

LAM Gev Field Free Region Scan

Position of 120 Gev Beam at HP608 Sigma 20  ~ 1.2 mm Shows a movement of 5mm

Summary of LAM62 Scan 8 Gev First turn using protons (060201) Assume 10  beam –Field Free Region Centroid of 8 Gev beam at HP620 is mm Inside loss start -52 mm on HP620 as seen on LM620A and B First loss seen on LM621 moving toward seputm at -19 mm on HP520 followed by LM620D with LM619C Loss free aperture 30 mm + 23 beam size -> ~53 mm –Field Region Lambertsons on at 8 Gev level-> bend protons up to hit the pole tip of Q620 which saturate loss monitors close to quad and raises background due to backscatter on loss monitors farther upstream When scanning from field region toward the septum, the beam strikes LAM62C septum first due to septum offsets Loss free width on LM619D is 21 mm followed by LM619E (both on LAM62C) and then on LM619C is 25 mm + beam size Loss on LM619C is back scatter. This loss monitor is not saturated and will be used to estimate beam size –Beam Size Comments Based upon beta at upstream end of LAM62C (28m) the sigma for a 10  should be 2.2 mm and 6 sigma should be 13.2mm. Use the non saturated LM619C loss monitor to estimate beam size by scanning the beam across the septum of LAM62C. Beam extends to about 21 mm full width which gives a 11.5mm half width which implies beam extends out to 5.3 .

Cartoon of LAM62 Layout Q620 LAM62A LAM62C LAM62B 2.54mm 5mm Field free region LM619C LM619D LM620A LM620B LM620D p PBARS

Circulating Field Free Region Extraction Field Region protons Pbars Q622 Q620 Q618

LAM62 8 Gev Field Free Region

Beam size from LAM62C septum scan

Summary of Horizontal Apertures

Cross Section at Q608 Beam out to about 6.5  on circulating beam Start loss with single pass beam Start loss with circulating beam Beam out to ~ 4.5  on 1 st turn beam Assume 10   ~ 3.1 mm +/-3 sigma beam at nominal HP608 position