Main Injector Gap clearing kickers Phil Adamson (#) AEM 14th March 2011

Increasing intensity for NuMI AEM 14th March 2011 MI Gap Clearing Kickers 2 11-batch slip-stacking

Slip-stacking  Neutrino experiments want more beam!  Inject 11 batches rather than 6  But pay for it with increased losses  (<95% efficiency) AEM 14th March 2011 MI Gap Clearing Kickers 3

Slip-stacking recapture (real data) AEM 14th March 2011 MI Gap Clearing Kickers 4

3 losses, 1 cause  Uncaptured beam at start of ramp  Extraction losses caused by beam in extraction gap  Beam in injection gap – lost downstream of injection kickers AEM 14th March 2011 MI Gap Clearing Kickers 5

Loss control in Main Injector  Avoid activation of tunnel components  ALARA  Uptime  Other loss mechanisms dealt with  MI-8 collimators  Scrape transverse tails before injection  MI-30 collimators  Lose uncaptured beam at collimators rather than Lambertsons  Fuzzer  Eliminate extraction loss by clearing beam from extraction gap at 8 GeV 6 AEM 14th March 2011 MI Gap Clearing Kickers

MeV -40MeV 0588 buckets Longitudinal simulation for 11 batch slip stacking AEM 14th March 2011 MI Gap Clearing Kickers 7

Idea: Gap Clearing Kickers  Problem: beam gets into injection gap, sprayed in region when kicker fires  Solution: build new kickers to send beam to abort instead  Kicker must have fast (3 bucket) rise and fall time to match injection kicker  But kick horizontally  In fact, requirements are almost identical to new NOvA RR injection kickers AEM 14th March 2011 MI Gap Clearing Kickers 8

Magnets built by TD  Fast rise/fall time, so need short magnets  7 magnets to generate necessary kick AEM 14th March 2011 MI Gap Clearing Kickers 9

2009 shutdown AEM 14th March 2011 MI Gap Clearing Kickers 10  Install magnets in tunnel

It’s not just a few magnets  Kickers need power supplies, PFLs etc.  Kickers need to fire at 15Hz (or will in a few years time), so need temperature- controlled load  We didn’t have building space  Didn’t have penetrations for fluorinert piping  Didn’t have penetrations for HV cables  To get fast rise/fall time, need many small kickers, so need lots of all this AEM 14th March 2011 MI Gap Clearing Kickers 11

2009 shutdown AEM 14th March 2011 MI Gap Clearing Kickers 12  Dig up berm to find top of tunnel  Drill through (carefully)

Then build a building AEM 14th March 2011 MI Gap Clearing Kickers 13

…and outfit it AEM 14th March 2011 MI Gap Clearing Kickers 14

2010 shutdown  Complete tunnel work  Cables  Fluorinert  October 2010  All kickers ready to go  Begin comissioning AEM 14th March 2011 MI Gap Clearing Kickers 15

GCK beam hits the dump AEM 14th March 2011 MI Gap Clearing Kickers 16  Abort  GCK

Kicker measurements AEM 14th March 2011 MI Gap Clearing Kickers 17  Inject beam into MI, fire kicker through it  Use MI damper to get bunch-by-bunch position measurement  Fit turn-by-turn data

Rising and falling edges AEM 14th March 2011 MI Gap Clearing Kickers 18  Edges within specification  Slower edge in damper measurement might be measurement artifact Damper (beam) measurement Calculated B from measured voltages

Kicker tail AEM 14th March 2011 MI Gap Clearing Kickers 19  For recycler, building “tail bumper” to cancel tail  Tail measurement similar to electrical measurements (good)

After NuMI returns AEM 14th March 2011 MI Gap Clearing Kickers 20 Kickers off

After NuMI returns AEM 14th March 2011 MI Gap Clearing Kickers 21 Kickers on. Circled loss due to steering error (later corrected).

Beam loss, region AEM 14th March 2011 MI Gap Clearing Kickers 11-batch slip-stacking 22 GCK on

Loss and activation AEM 14th March 2011 MI Gap Clearing Kickers 23 Green points: contact measurement at V105 GCK on for a week Already as low as end of 2009 shutdown

Increased beam power AEM 14th March 2011 MI Gap Clearing Kickers 24  Reached 400 kW in Main Injector  Looking forward to NuMI’s return 401 kW

Gap-Clearing Kickers: a successful AD/TD collaboration AEM 14th March 2011 MI Gap Clearing Kickers 25  AD (power supply and vacuum components)  Christine Ader  Rob Reilly  Chris Jensen  George Krafczyk  Jim Biggs  Steve Ward  plus 12 technicians  TD (magnets)  George Velev  Iouri Terechkine  Bob Jensen  Bill Robotham  Ollie Kiemschies  plus 5 technicians

The remaining loss spike AEM 14th March 2011 MI Gap Clearing Kickers 26  Opened up 113 location last week  Found problem