**RHIC Mid-Term Strategic Plan: 2006-2011**

**Interim Report to PAC**

**10/26/05; rev. 11/2/05**

**T. Ludlam, for the Working Group**

*Note: This is an interim report to the PAC, providing a snapshot of the
Working Group's findings and initial conclusions. It is not a draft of a
final report. That will come in mid-December, and will incorporate
feedback from the PAC.*

The aim of the mid-term strategy is to map out an achievable, aggressive
program of detector upgrades and facility utilization that will maximize
the scientific impact of the RHIC program in the years 2009 and beyond,
when RHIC will start to compete with the LHC heavy ion program. This
Mid-Term Plan is being developed specifically in response to two
recommendations of the July 2005 DOE Science and Technology Review of
RHIC:

-   Develop a mid-term strategic plan which includes the implementation
    of necessary detector upgrades in the context of scientific
    priorities, expected machine performance, and the expected turn-on
    of the Large Hadron Collider (LHC). This plan should be cognizant of
    the DOE needs for formulating federal budgets and requirements for
    project management. The plan should be submitted to DOE by January
    2006.

-   Update the RCF five-year plan to consistently reflect the needs of a
    five-year run plan in the context of projected detector upgrades and
    accelerator performance. This plan should be complete and submitted
    to DOE by January 2006. This report may be combined with the
    mid-term strategic plan provided the RCF plan is a prominent
    component.

To be specific with regard to the first charge, we take the "mid-term"
period to be the years 2006-2011. In addressing this strategy, we have
kept in mind the long range planning for RHIC. In this regard, under
favorable budget circumstances, the mid-term phase leads directly into
operation of the collider at high luminosity with e-cooling, so the
strategy should be consistent with achieving high-luminosity
configurations of STAR and PHENIX, as well as providing computing
resources via the RHIC Computing Facility (RCF) to deal with the
corresponding increases in data volume and analysis requirements of the
experiments. Thus, this Mid-Term Strategy will serve to illuminate the
technically driven schedule and scope of RHIC II.

The mid-term strategic plan is being developed by a working group
established by Sam Aronson early in September. The group is broadly
representative of the two major experiments, including both the heavy
ion and spin interests. It includes the leadership of RCF and the
accelerator team responsible for machine development and upgrades in the
C-A department. The planning group includes two members of the BNL
theory group, and two leaders of the BRAHMS and PHOBOS collaborations
who provide their own perspective on the future program at RHIC and its
relation to the LHC heavy ion program. In addition, the working group
has included the computing leaders for PHENIX and STAR in its
discussions of the RCF planning. The membership of the planning group is
listed in Table 1.

> T. Ludlam, convenor
>
> S. Aronson, *ex officio*
>
> PHENIX: A. Drees, E. O'Brien, W. Zajc, A. Deshpande
>
> STAR: R. Majka, T. Hallman, B. Surrow
>
> C-AD: P. Pile, W. Fischer, T. Roser
>
> RCF: B. Gibbard, T. Throwe
>
> Theory: D. Kharzeev, W. Vogelsang
>
> RHIC Spin: G. Bunce
>
> At Large: M. Baker, F. Videbaek
>
> Consultants on Exp. Computing: J. Lauret, D. Morrison

**Table 1: Working Group Membership**

The working group has had four meetings to date, on Sept. 28, Oct. 5,
Oct. 12, and Oct. 20. We have heard formal presentations from the PHENIX
and STAR collaborations on their detector upgrade plans. We have also
had presentations from the Collider-Accelerator group on machine
development and performance expectations, and from RCF on the current
status and mid-term planning for the computing facility. These
presentations are posted on the working group web site:

www.rhic.bnl.gov/midterm/

Based on the group's findings and discussions so far, the elements of a
strategic plan are emerging. More work needs to be done to knit these
elements into a coherent plan that reflects the physics vision of the
RHIC community and integrates a program of machine operation, detector
upgrades, and a supporting evolution of RCF that can realistically be
submitted to DOE as a basis for program planning over the next several
years. We briefly outline here the elements of this plan.

**Physics goals for the mid-term:**

Spectacular early results raise important questions about new state of
matter.

The mid-term strategy outlined here calls for a balance of beam-on
running time with investment in accelerator and detector upgrades
necessary for crucial measurements of this new form of dense matter, and
a full realization of the RHIC spin capability.

Heavy Ion measurements:

*Detector and facility upgrades to address these measurements are shown
in italics. The upgrades are discussed below.*

-   Electron-pair mass spectrum (DOE performance milestone for 2010)

*Hadron Blind Detector for Dalitz pair rejection*

-   Open charm measurements in AA

> *High resolution vertex detection*

-   Charmonium spectroscopy (DOE performance milestone for 2010)

> *High luminosity; precision vertex; improved particle ID*

-   Jet Tomography

> *High luminosity; High-rate DAQ; improved particle ID*

-   Monojets in d-Au (DOE performance milestone for 2012)

> *Particle detection at forward rapidity*

Spin measurements:

-   Complete initial ∆G/G measurement (DOE performance milestone for
    2008)

> *No upgrades needed*

-   Transversity measurement

> *Forward particle measurement*

-   W measurements at 500 GeV (DOE performance milestone for 2013)

> *Forward trigger in PHENIX and tracking in STAR*

**Collider upgrades and development: 2006-2011**

The Collider group continues to enhance the machine performance through
developments as part of the ongoing operations. At present, the achieved
Au-Au luminosity is about twice the design value. Over the next few
running periods the ion-ion luminosity, averaged over a store, is
expected to increase by another factor of \~2, reaching an average per
store (Au-Au collisions) of 8 x 10^26^ cm^-2^sec^-1^.

The p-p luminosity, while it exceeds the design luminosity for RHIC, is
less than the target value for carrying out the RHIC spin program. The
polarization has increased steadily to a value, in run 5, of \~50%. Over
the next several years the luminosity is expected to increase by a
factor of 6 over the presently achieved value, reaching 6 x 10^31^
cm^-2^sec^-1^ at 100+100 GeV and 1.5 x 10^32^ cm^-2^sec^-1^ at 250+250
GeV. These values assume collisions in 2 IRs. The polarization is
expected to reach the design value of 70% during Run 6.

The DOE construction start of EBIS will begin in FY 2007. The NASA
supported part of the project began in late FY 2005. EBIS is a
linac-based ion source and pre-injector that will replace the Tandems,
providing more efficient, lower-cost operation. It is expected to be
commissioned in 2009, and will make high-luminosity uranium beams, as
well as polarized ^3^He available for experiments.

R&D is underway on electron cooling of the full-energy ion beams in
RHIC. By eliminating beam blow-up due to intra-beam scattering, this
will provide an increase in Au-Au luminosity by a factor of \~10, and is
the basis for the RHIC II upgrade. A demonstration Energy Recovering
Linac is being built, with funds from both DOE and the U.S. Navy.
Development of SC cavities and high-brightness electron gun is underway.
Codes to simulate beam blow-up and cooling are being benchmarked. It is
expected that a "proof of principle" for e-cooling in RHIC will be
established and peer-reviewed during FY 2006. From a technical
stand-point, a project to implement e-cooling for RHIC II will be ready
for CD-0 determination by DOE in FY2006, leading to a construction start
(CD-3) in 2009, and implementation \~2013.

**PHENIX and STAR Upgrades**

Each of the experiments has a planned suite of upgrades to address the
physics topics described above. We give a brief listing here, noting the
status of each. We have divided them into "short term" and "mid-term"
upgrades. The short term upgrades are projects that either already
underway, or expected to proceed in FY 2006. The mid-term upgrades are
projects that are far enough along in the planning/development/proposal
stage that they could be implemented as DOE construction projects and
completed during the time window of this strategic plan.

In discussing these projects in the context of the strategic plan, we
have considered the resources required to implement them, including
manpower; the costs and expected funding sources; the R&D requirements,
including R&D costs; the incremental operations costs and computing
resources once the upgrade becomes operational; and the timing of these
upgrades with respect to possible physics operations scenarios for the
facility. Thus, for example, the planning for the next high-statistics
Au-Au run is coupled to the availability of detector upgrades to allow
direct observation of open charm. These considerations are the subject
of the "integrated plan" for upgrades that we discuss below.

[Short Term Upgrades:]{.underline}

PHENIX Hadron Blind Detector (HBD):

> A proximity focused Cherenkov detector using CsI coated GEM detectors
> to detect soft electrons from Dalitz decays, reducing by orders of
> magnitude the combinatorial background for the low-mass spectrum of
> electron pairs. The project is being led by the Weizmann Institute.
> The DOE cost is \$1.1M, funded from RHIC operations capital (\$0.5M of
> this was provided in FY 04-05). A full size prototype is installed for
> an engineering run in Run 6. The detector should be operational for
> Run 7.

PHENIX Muon Trigger:

> A Resistive Plate Chamber array for each of the Muon Arms, providing
> an efficient trigger on leptonic W decays. This is essential for the
> PHENIX W measurements in the 500 GeV spin program. This project is
> funded by the NSF, at a cost of \~\$2M, and is led by the UIUC group.
> Construction is scheduled to begin in FY 2007, with completion in
> 2009.

STAR Time of Flight (TOF):

> A fast, fine-grain barrel array of Multi-gap resistive plate chambers
> (MRPC) that will surround the STAR TPC. This is a line-item (MIE)
> project with a DOE cost of \$4.7M. It is funded for a start in FY
> 2006, with completion in 2009. The MRPC modules will be fabricated in
> China.

STAR Forward Meson Spectrometer (FMS):

> A Pb glass array of \~1400 existing blocks, covering the η range from
> 1-4. Will provide neutral pion measurements in the range x = .001 - .1
> in Au-Au and d-Au collisions. Funded from RHIC operations capital, at
> a cost of \$600K. Expected to be fully operational in FY 2007.

STAR DAQ1000:

> Replaces the front-end electronics of the STAR TPC with a fully
> pipelined system using the readout chip designed for the ALICE TPC.
> This will increase the readout rate from its present 100Hz to 1000 HZ,
> increasing live time for triggered events by a factor of 2, allowing
> very large untriggered samples, and efficient triggering on rare
> events with, e.g., the STAR EM calorimeter. Funded from RHIC
> operations capital at a cost of \$1.8M (of which \$0.3M was funded in
> FY 05), it should be implemented by FY 2008.

[Mid-Term Upgrades]{.underline}

PHENIX Si Barrel Vertex Detector:

> A 3-layer silicon detector using pixels and strips to provide tracking
> with sufficient accuracy to detect displaced vertices of charm and
> beauty decays. This is a joint U.S. and Japanese effort. The U.S.
> component is proposed as an MIE project with a DOE cost of \$4.7M. It
> has been reviewed, and a management plan accepted by DOE. It is
> expected to be funded for a construction start in FY 2007, with
> completion in 2009.

PHENIX Si Forward Vertex Trackers:

> Two "end-cap" silicon trackers that will increase the rapidity
> coverage of the Si barrel, extending displaced-vertex coverage to
> include the acceptance of the Muon Arms. The proposed DOE cost would
> be \~\$4.5M. There is not yet a formal proposal for this project.

PHENIX Nose Cone Calorimeter (NCC):

> A project to instrument the pole pieces of the PHENIX axial field
> magnet with a compact, dense sampling calorimeter using tungsten
> plates interleaved with silicon readout. These will provide forward
> photon and jet coverage for the PHENIX heavy ion and spin
> measurements. The NCC is being developed by a collaboration of U.S.,
> Japanese, Russian, and Czech institutions. A full technical design is
> not yet prepared. The estimated DOE cost is \$4M.

STAR Heavy Flavor Tracker (HFT):

> A silicon pixel inner tracking device with vertex point-back accuracy
> \<50 μm, consisting of two layers of CMOS active pixel sensors, 10^8^
> pixels, thin, 2 cm radius beam pipe, with detector thickness \~ 50μm
> per layer. This is an on-going development effort, with expectation
> that a project to construct a functioning detector for STAR could be
> undertaken in 2-3 years. The cost would be in the range \$5-10M.

STAR Inner/Forward Tracking (integrated tracker)

> A silicon barrel consisting of 3 layers of Si strip detectors,
> replacing the present SVT, surrounding the HFT, and utilizing the
> existing SSD Si strip layer, provides a track pointing device for the
> HFT, connecting TPC tracks to the high precision inner layers,
> compatible with DAQ 1000. Forward tracking consists of 4 Si strip
> discs just forward of the Si barrel, and a GEM layer on the front face
> of the Forward EM Calorimeter. The forward tracking components provide
> precision tracking in the range 1 \< η \< 2, giving charge sign
> discrimination for W decays. The estimated cost is \~\$10M.

In Table 2 we summarize the estimated costs and schedules for these
upgrades. Only the DOE costs are shown. Here, the estimates for the
short-term upgrades are well-established. For the mid-term upgrades we
have provided the current best estimates. The schedules shown for the
mid-term upgrades include the time required for review of technical
designs and management plans by BNL and DOE in advance of the budget
preparation cycle for the proposed construction start. (Thus, for
example, proposed project starts in FY 2008 must be reviewed by mid-FY
2006).

> **Table 2.**
>
> **Detector upgrade cost profiles (DOE costs): R&D and Construction**

![](media/image1.wmf){width="6.0in" height="2.4694444444444446in"}

The total annual R&D and equipment fabrication costs for detectors in FY
2005 and 2006 is about \$6M per year. In Table 2 one sees that this
annual investment would rise to an average level of about \$7-8M per
year for the period 2007 -- 2010 in order to implement these upgrades.

The working group is in the process of estimating the incremental annual
operating costs for the RHIC facility as these upgrades come on-line. At
present we have only a very rough estimate, based on rules of thumb,
indicating that the operations costs would increase by approximately
\$1-2M per year for the detectors. This is approximately balanced by the
reduced operating costs of the accelerator complex when EBIS comes on
line.

**RHIC Computing Facility**

*Note: A detailed response to the DOE call for a 5-year plan is being
developed, based on the overall mid-term strategic plan. This will be
incorporated in the final report. We give a brief overview here for the
interim report.*

The RCF concept of a scalable architecture for CPU, disk, and mass
storage, with annual replacement of \~1/4 of the installed hardware, has
been successful in supporting the early runs at RHIC. Working with the
experimental groups, RCF has developed algorithms to estimate the
required capacities for CPU, disk, and mass storage for anticipated RHIC
running scenarios. These algorithms, based primarily on the expected
amount of raw data collected, allow for flexible planning and cost
estimating based on multi-year beam use plans.

CPU has historically been the primary driver of RCF equipment costs. To
date, the predictability of Moore's Law has been excellent for
increasing CPU capacity through annual purchase of new hardware. New
Dual Core Processor technology promises a significant price/performance
enhancement. Growth in data volume and data recording rates has outpaced
early expectations, hence RCF is moving toward cheaper (more
commodity-like) solutions for mass storage.

In general, we do not foresee a significant change in the RCF
architecture through the mid-term period. Nor do we see a significant
increase in the annual cost of RCF operation during this period.
However, a detailed study of the impact on data volume of the proposed
detector upgrades is being carried out. The final report of this
planning study will include an estimate of the incremental need for
computing support, and the effect on RCF plans and equipment costs. It
is worth noting that both PHENIX and STAR have made use of computing
resources outside of RCF for data simulation and processing. In
particular, this year, PHENIX utilized high-speed network connection to
process the Run 5 p-p data at its computing center in Japan.

A very serious issue for RCF relates to physical infrastructure. The
scale of computing has grown to the point where the physical hardware
has outgrown the available floor space and associated power and cooling
capacity. By the spring of 2007 additional floor space, with
accompanying power, air conditioning, fire detection/suppression, etc.
will have to be provided. This problem is being studied at the
Laboratory level. While it is not expected that the cost of providing
this infrastructure will be passed to the RHIC budget, there may be
increased annual operating costs as a result.

**An Integrated Strategic Plan**

Based on the findings discussed above, the working group believes that
the mid-term accelerator and detector upgrades could proceed over the
coming 5-6 years while carrying out a physics operations program of
20-30 weeks each year. This could be accomplished with annual operating
costs at a level of constant effort relative to FY 2005 funding, except
for an increase in capital equipment funding of \$1-2M/yr in the period
FY 2007-FY 2010, and non-DOE funding, as noted in the discussion of
detector upgrades. In Figure 1 we show a time-line in which we have
assumed a straw-man beam-use program that is consistent with (if not
exactly congruent with) the recent Beam Use Proposals from PHENIX and
STAR, and is also consistent with the present C-A Dept. projections for
beam performance over this period.

![](media/image1.wmf)

**Figure 1**

**A Mid-Term timeline for physics operation and upgrades**

A key element of this timeline is the readiness for high-statistics
Au-Au runs from 2009 onward. This corresponds to the time when we expect
the first results to emerge from the LHC heavy ion program. An important
part of the strategy, reflected in the funding plan of Table 2, is to
complete a complement of detector upgrades to enable measurements of
open charm (and beauty), charmonium spectroscopy, and jet tomography in
a high-statistics Au-Au run starting no later than 2009. Also in the
mid-term time period, the forward tracking and calorimetry upgrades
should enable the measurement of W^±^ production in 500 GeV p-p
collisions.

We have noted that the development of e-cooling is proceeding at a pace
that should allow the initiation of a construction project to implement
full-energy cooling of the RHIC beams, producing the RHIC II luminosity
gains, with a construction start (CD-3) in 2009. With the completion of
the detector upgrades listed in Table 2, both STAR and PHENIX will be
fully capable of exploiting the RHIC II luminosity to carry on with the
physics program described at the beginning of this report, and in the
findings of the RHIC II Science working groups.

Therefore, an important consequence of the mid-term strategy described
here is the possibility to re-visit the planned scope of the RHIC II
Project, which had previously been envisioned to include significant
funding for detector upgrades. We suggest that with the implementation
of this mid-term plan, a RHIC II Project can be more narrowly defined,
strictly as a luminosity upgrade for the machine. At correspondingly
lower cost, this major upgrade in machine performance could become
operational at the end of the mid-term period, with two large detectors
well equipped for RHIC II physics. The graphic in Figure 2 illustrates
this plan in detail, showing the timeline for machine and detector
upgrades along with the evolution of machine capability over the
mid-term period, and the corresponding readiness to begin the key
physics measurements.

![](media/image1.wmf)

**Figure 2**

**Graphic illustration of the Mid-Term Plan**