# Presentation: 679322

## PHENIX Run8 Summary - Mike Leitch

- PHENIX Run Coordinator
-  Luminosity & Overall Performance
-  Critique
-  Spin goal reality check
-  Vertex efficiency issues
-  J/ Signals
-  Low Energy Au+Au

- Projected Run8 dAu J/ RdAu improvement

- 3/31/2008

- PHENIX - MJL

## dAu

- PHENIX - MJL

-  peaks above 3 nb-1 per day
-  one day > total Run3 luminosity of 2.7 nb-1

| Run | Energy | Long. | Trans. |
| --- | --- | --- | --- |
| 02 | 200 GeV |  | 0.15 pb-1 |
| 03 | 200 GeV | 0.35 pb-1 |  |
| 04 | 200 GeV | 0.12 pb-1 |  |
| 05 | 200 GeV | 3.4 pb-1 | 0.16 pb-1 |
| 06 | 200 GeV | 7.5 pb-1 | 2.7 pb-1 |
| 06 | 62.4 GeV | 0.08 pb-1 | 0.02 pb-1 |
| 08 | 200 GeV |  | 5.2 pb-1 |

- 5.2 pb-1 200 GeV p+p Transverse Vertical luminosity recorded
- (1.1 pb-1 FOM)
- Peak luminosity per day ~0.37 pb-1

- pp -  almost no progress on luminosity & polarization development towards future

## 200 GeV d+Au

- PHENIX - MJL

*Black vertical lines are markers for Maintenance and/or APEX days*

-  Live Time – 89%
-  PHENIX up – 77%
-  Overall (w/o vertex) – 68%

- 200 GeV p+p
-  Live Time – 89%
-  PHENIX up – 69%
-  Overall (w/o vertex) – 62%
- (where 10% correction for loss due to CNI measurements is made)

- Vertex eff ~50% in both cases!
-  will be improved by Stochastic Cooling (SC) & RF advances
-  but vertex detector upgrades use ±10 cm so even with SC can expect only 38% eff!!

**Notes:**
dAu – BBC 88%x2.26b, ZDC 0.52 b; pp – BBC 53%x42mb, ZDC 0.31 mb

## Waste No Rare Triggers – the PHENIX Strategy

- PHENIX - MJL

**thresh:**
**2.8 GeV**
**3.5 GeV**
**2.1 GeV**

- Actual trigger setup & rates for one of the hottest Run8 dAu runs
-  > 90% livetime
-  85khz MB (BBCVtxCut) rate

-  J/  +-

-  J/  e+e-

-  central-arm
******,********0****,********±**, etc

- MPC Forward
- Calorimeter

*(32 triggers total – some not shown)*

## Beam & Polarization related Issues

-  Control of backgrounds needs to improve
-  blue was always worse in dAu
-  Auto-orbit corrections every 1⁄2 hr affect backgrounds
-  need to be accompanied by auto collimator adjustments that follow orbit movement at collimators
-  Vernier scans
-  need prompt analysis results posted on web
-  better communication with experiments
-  some longer scans to facilitate event analysis at experiments
-  Can the “physics” signal be sent to experiments for consistent luminosity counting?

-  Uncertain funding & schedule is inefficient – obviously
-  Is there any way to improve this???
-  Still no 1st look at 500 GeV collisions, a key part of the future pp program!
-  A surprise that 9 Mhz cavity not ready for Run8 - when will it be?
-  Low polarization (50% blue, 41% yellow on 2004 scale!)
-  very little polarization ramp-up/development time
-  PHENIX forced to forgo radial polarization to enable luminosity development (x1/2.3 significance)
-  anti-correlation with luminosity a serious problem!

- 3/31/2008

- PHENIX - MJL

## Beam & Polarization related Issues

-  Jet measurements were good, but changes between blue & yellow were disruptive
-  CNI measurements were not ready until few weeks into run
-  CNI measurements cost significant (~10%) expt uptime due to backgrounds they create (PHENIX turns off)
-  is this counted (by CA) as “physics” luminosity?
-  can measurement time be shorter?
-  can expts take data during measurements?
-  find way to avoid losing CNI targets
-  better (more automatic?) communication with expts
-  Local (expt) Polarimeters are important
-  can they be faster & better?
-  results available promptly/automatically on web?
-  PHENIX Local-Pol data limited by main PHENIX DAQ bandwidth
-   Is it worth investment in new detector, FEE or dedicated DAQ in order to get higher accuracy results faster?

- 3/31/2008

- PHENIX - MJL

## Other Issues

-  PHENIX ok thanks to large local “buffer boxes” and policy to keep data on them until we need the space for new data (takes only 15 min to clean off)
-  prompt notification of failures to experiments is important

-  Heating in PHENIX control room inadequate
-  owl shifts on cold nights very cold
-  need to replace heater coils before next run
-  Air conditioning ok except for substation ground-fault caused by NW IR air conditioner

- 3/31/2008

- PHENIX - MJL

-  New IRIS scanner is a pain in the neck
-  installed w/o warning after beam operations had started
-  keys from MCR were necessary then, and sometimes later
-  why was this not reviewed as to impact & planning?
-  many problems during run
-  totally dead – had to get keys from MCR or get expert to reboot it
-  recognizes user but won’t release key
-  “violation” error & continuous audible alarm for hours
-  operator GUI at MCR doesn’t see key taken

## PHENIX Spin Physics Goals – Can we Get there from here?

- 3/31/2008

- PHENIX - MJL

- ALL(0) goal is 71 pb-1 with 65% polarization
-  gluon contribution (G) to the nucleon spin

- 500 GeV W goal is about 300 pb-1 recorded at 70% polarization
-  dbar, ubar contribution to the nucleon spin

- Radial Polarization goal was 7.5-10 pb-1 at 60% polariz.
-  Sivers – (7.5*0.602)/(5.2/2.3*0.5*0.41) = 5.8 short of goal
-  factor of 2.3 due to not having Radial polarization
-  Mono-jets – pp is baseline for dAu
-  MPC on both sides (unlike STAR) is a plus

- Run9 – Likely need p+p 1st – can’t live another year without a STRONG pp run with ample development towards higher FOM!

## The Persistent Problem of Interaction Diamond Sizes

- PHENIX - MJL

- With present interaction diamond z-size PHENIX gets about a factor of two loss in luminosity with our ±30 cm vertex cut (see earlier slide)
-  with Stochastic Cooling (longitudinal) and full voltage 200 Mhz RF it is thought that the vertex can be narrowed to ±20 cm for AuAu collisions
-  super Beta quads could help
-  for pp collisions 9 Mhz cavity will help?
-  but the Vertex detector upgrades require ±10 cm cuts, which even for ±20 cm distributions, will give only a 38% efficiency!
-  I guess STAR will have similar issues
-  also some loss? (~20%) for beam in non-central buckets – 56 Mhz cavity (2012) should help with this

## PHENIX J/’s from Run8

- 3/31/2008

- PHENIX - MJL

- PHENIX J/’s from Run8

## 9.2 GeV 2-day test Run

- 3/31/2008

- PHENIX - MJL

- Few hz rate of BBCLL1 without a vertex cut

- Short stores
- ±1.5 meter int. region

- Small fraction of triggers inside BBC z region with large beam-gas like side peaks

- 19% in ±100 cm
- 7.3% in ±30 cm

## Backup Slide(s)

- PHENIX - MJL

*Backup Slide(s)*

## The Optimistic Scenario for Spin Physics Goals

- PHENIX - MJL

-  Major Spin Physics Goals
-  ALL(0) @ 200 GeV – 71 pb-1 at 65% polarization
-  W @ 500 GeV – 300 pb-1 at 70% polarization
-  assume L500GeV/L200GeV = 2.5
-  assume luminosity recorded/delivered = 1/3
-  Luminosity & polarizaton from CA planning document

| Scenario | Lumi/wk
(delivered) | Polariz | #weeks to reach goal |  |
| --- | --- | --- | --- | --- |
|  |  |  | ALL | W |
| Run6 Achieved | 7 pb-1 | 60% | 42 wks | 70 wks |
| Run9 Projected | 14 pb-1 | 65% | 15 wks | 30 wks |
| 2013E max Projected | 39.8 pb-1 | 75% |  | 8 wks |

-  9 Mhz RF cavity
-  LEBT/MEBT (transfer line) improvements
-  Triplet 10hz reduction
-  Electron lens
-  56 Mhz RF
-  Polarized source upgrade

- Expected advances: